Survex 1.2.30 Manual

Olly Betts

<olly@survex.com>

Wookey

<wookey@survex.com>

Copyright © 1998-2016 Olly Betts

This is the manual for Survex - an open-source software package for cave
surveyors.

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Introduction

This section describes what Survex is, and outlines the scope of this manual.

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About Survex

Survex is a multi-platform open-source cave surveying package. Version 1.2 runs
on UNIX, Microsoft Windows, and Mac OS X. We're investigating support for
phones and tablets.

We are well aware that not everyone has access to super hardware - often
surveying projects are run on little or no budget and any computers used are
donated. We aim to ensure that Survex is feasible to use on low-spec machines.
Obviously it won't be as responsive, but we intend it to be usable. Please help
us to achieve this by giving us some feedback if you use Survex on a slow
machine.

Survex is capable of processing extremely complex caves very quickly and has a
very effective, real-time cave viewer which allows you to rotate, zoom, and pan
the cave using mouse or keyboard. We have tested it extensively using CUCC and 
ARGE's surveys of the caves under the Loser Plateau in Austria (over 25,000
survey legs, and over 140km of underground survey data). This can all be
processed in around 10 seconds on a low-end netbook. Survex is also used by
many other survey projects around the world, including the Ogof Draenen survey,
the Easegill resurvey project, the OFD survey, the OUCC Picos expeditions, and
the Hong Meigui China expeditions.

Survex is still actively being worked on. Version 1.0 was complete in some
sense, but development continues - initially in reshaping Survex into a more
integrated GUI package.

We encourage feedback from users on important features or problems, which will
help to direct future development. See the "Mailing List" section of this
manual for the best way to contact us.

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About this Manual

If there's a part of this manual you find hard to understand, please do let us
know. We already know Survex well, so it can be hard for us to spot areas where
the manual doesn't given enough information, or doesn't explain things clearly
enough to follow when you don't know what's going on. It's helpful is you can
suggest a better wording, but don't worry if you can't, just explain the
problem as precisely as you can.

The master version of this manual is an SGML document written using the docbook
DTD, and automatically converted to a number of other formats. If you are going
to send us major changes, it's much easier to include them if you work from
this master. You can get it from the source archive (docs/manual.sgml) or from
the Survex website.

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Terminology

Throughout this document we use British terminology for surveying.

station

    a point in the cave that you survey from and/or to

leg

    a line joining two stations

survey

    a group of legs surveyed on the same trip

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Getting Started

This section covers how to obtain the software, and how to unpack and install
it, and how to configure it.

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Obtaining Survex

The latest version is available from the Survex website: https://survex.com/.
It is also freely redistributable, so you welcome to get a copy from someone
else who has already downloaded it.

If you want some sample data to experiment with, you can download some from the
Survex website too: https://survex.com/software/sample.tar.gz

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Installing Survex

The details of installation depend greatly on what platform you are using, so
there is a separate section below for each platform.

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Linux

We supply pre-compiled versions for x86 Linux machines in RPM format (suitable
for Redhat, Mandrake, and some other distributions). Survex Debian packages are
available from Debian mirror sites in the usual way.

You'll need root access to install these prebuilt packages. If you don't have
root access you will need to build from source (see the next section).

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Other versions of UNIX

For other UNIX versions you'll need to get the source code and compile it on
your system. Unpack the sources and read the file called INSTALL in the top
level for details about building from source.

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Microsoft Windows

This version comes packaged with an installation wizard. Just run the
downloaded package and it will lead you through the installation process. If
you want the file associations to be set up for all user, run the installer as
administrator, or as a user with administrator rights.

The survey viewer that's part of Survex is called aven, and uses OpenGL for 3d
rendering.

If you find that 3D rendering is sometimes very slow (e.g. one user reported
very slow performance when running full screen, while running in a window was
fine) then try installing the OpenGL driver supplied by the manufacturer of
your graphics card rather than the driver Microsoft supply.

The installer creates a Survex group in the Programs sub-menu of the Start menu
containing the following items:

  • Aven

  • Documentation

  • Uninstall Survex

Icons are installed for .svx, .3d, .err, and .pos files, and also for Compass
Plot files (.plt and .plf) (which Survex can read). Double-clicking on a .svx
file loads it for editing. To process it to produce a .3d file, right click and
choose "Process" from the menu. Double-clicking the resultant .3d file views it
in aven. All the Survex file types can be right clicked on to give a menu of
possible actions.

.svx

    Process

        Process file with aven to produce .3d file (and .err file)

.3d

    Open

        Load file into Aven

    Print

        Send to the printer

    Extend

        Produce extended elevation

    Convert to DXF

        Convert to a DXF file (suitable for importing into many CAD packages)

    Convert for hand plotting

        Produce a .pos file listing all the stations and their coordinates

.err

    Open

        Load file into Notepad

    Sort by Error

        Sort .err file by the error in each traverse

    Sort by Horizontal Error

        Sort .err file by the horizontal error in each traverse

    Sort by Vertical Error

        Sort .err file by the vertical error in each traverse

    Sort by Percentage Error

        Sort .err file by the percentage error in each traverse

    Sort by Error per Leg

        Sort .err file by the error per leg in each traverse

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Configuration

Selecting Your Preferred Language

Survex has extensive internationalisation capabilities. The language used for
messages from Survex and most of the library calls it uses can be changed. By
default this is picked up from the language the operating system is set to use
(from "Regional Settings" in Control Panel on Microsoft Windows, from the LANG
environment variable on UNIX If no setting is found, or Survex hasn't been
translated into the requested language, UK English is used.

However you may want to override the language manually - for example if Survex
isn't available in your native language you'll want to choose the supported
language you understand best.

To do this, you set the SURVEXLANG environment variable. Here's a list of the
codes currently supported:

┌─────┬──────────────────────┐
│Code │       Language       │
├─────┼──────────────────────┤
│en   │International English │
├─────┼──────────────────────┤
│en_US│US English            │
├─────┼──────────────────────┤
│bg   │Bulgarian             │
├─────┼──────────────────────┤
│ca   │Catalan               │
├─────┼──────────────────────┤
│de   │German                │
├─────┼──────────────────────┤
│de_CH│Swiss German          │
├─────┼──────────────────────┤
│el   │Greek                 │
├─────┼──────────────────────┤
│es   │Spanish               │
├─────┼──────────────────────┤
│fr   │French                │
├─────┼──────────────────────┤
│hu   │Hungarian             │
├─────┼──────────────────────┤
│id   │Indonesian            │
├─────┼──────────────────────┤
│it   │Italian               │
├─────┼──────────────────────┤
│pl   │Polish                │
├─────┼──────────────────────┤
│pt   │Portuguese            │
├─────┼──────────────────────┤
│pt_BR│Brazillian Portuguese │
├─────┼──────────────────────┤
│ro   │Romanian              │
├─────┼──────────────────────┤
│ru   │Russian               │
├─────┼──────────────────────┤
│sk   │Slovak                │
├─────┼──────────────────────┤
│zh_CN│Chinese (Simplified)  │
└─────┴──────────────────────┘

Here are examples of how to set this environment variable to give messages in
French (language code fr):

Microsoft Windows

    For MS Windows proceed as follows (this description was written from MS
    Windows 2000, but it should be fairly similar in other versions): Open the
    Start Menu, navigate to the Settings sub-menu, and open Control Panel. Open
    System (picture of a computer) and click on the Advanced tab. Choose
    `Environmental Variables', and create a new one: name SURVEXLANG, value fr.
    Click OK and the new value should be effective immediately.

UNIX - csh/tcsh

    setenv SURVEXLANG fr

UNIX - sh/bash

    SURVEXLANG=fr ; export SURVEXLANG

If Survex isn't available in your language, you could help out by providing a
translation. The initial translation is likely to be about a day's work; after
that translations for new or changed messages are occasionally required.
Contact us for details if you're interested.

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Survex Programs

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Standard Options

All Survex programs respond to the following command line options:

--help

    display option summary and exit

--version

    output version information and exit

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Short and Long Options

Options have two forms: short (a dash followed by a single letter e.g. cavern
-q) and long (two dashes followed by one or more words e.g. cavern --quiet).
The long form is generally easier to remember, while the short form is quicker
to type. Options are often available in both forms.

    Note: Command line options are case sensitive, so "-B" and "-b" are
    different (this didn't used to be the case before Survex 0.90). Case
    sensitivity doubles the number of available short options (and is also the
    norm on UNIX).

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Filenames on the Command Line

Filenames with spaces can be processed (provided your operating system supports
them - UNIX does, and so do recent versions of Microsoft Windows). You need to
enclose the filename in quotes like so: cavern "Spider Cave"

A file specified on the command line of any of the Survex suite of programs
will be looked for as specified. If it is not found, then the file is looked
for with the appropriate extension appended. So cavern survey will look first
for survey, then for survey.svx.

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Command Reference

Table of Contents
cavern -- process raw survey data
aven -- sophisticated cave viewer for Unix and MS Windows
3dtopos -- produce a .pos file from a .3d file
cad3d -- convert a Survex .3d file into formats which can be read by CAD and
    drawing packages
diffpos -- compare the contents of two .3d files
extend -- produce an extended elevation from a .3d file
sorterr -- re-sort .err file by various criteria

cavern

Name

cavern -- process raw survey data

Synopsis

cavern [options] {survex data file...}

Description

Cavern is the Survex data processing engine.

If multiple survey data files are listed on the command line, they are
processed in order from left to right. Settings are reset to their defaults
before processing each file.

Options

-o, --output=OUTPUT

    Sets location for output files.

-q, --quiet

    Only show a brief summary (--quiet --quiet or -qq will display warnings and
    errors only).

-s, --no-auxiliary-files

    do not create .err file.

-w, --warnings-are-errors

    turn warnings into errors.

--log

    Send screen output to a .log file.

-v, --3d-version

    Specify the 3d file format version to output. By default the latest version
    is written, but you can override this to produce a 3d file which can be
    read by software which doesn't understand the latest 3d file format
    version. Note that any information which the specified format version
    didn't support will be omitted.

Output

Cavern reads in text files containing the survey data .svx) and outputs two
files, with the extensions .3d and .err. By default these files are put in the
current directory, with the same base filename as the first .svx file read, but
a different extension. You can change the directory and/or base filename using
the --output command line option.

E.g. if you process the data file entrance.svx with the command cavern entrance
then the files entrance.3d and entrance.err will be created.

Cavern also gives a range of statistics at the end of a successful run:

  • The highest and lowest stations and the height difference between them

  • The total length of the survey (before and after adjustment). This total
    excludes survey legs flagged as SURFACE, DUPLICATE, or SPLAY.

  • The number of stations and legs. Note that a *EQUATE is counted as a leg in
    this statistic.

  • The East-West and North-South ranges, and the North-most, South-most,
    East-most, and West-most stations.

  • The number of each size of node in the network (where size is number of
    connections to a station) i.e. a one node is the end of a dead-end
    traverse, a two-node is a typical station in the middle of a traverse, a
    three-node is a T-junction etc.

  • How long the processing took and how much CPU time was used.

.3d - data describing the loop-closed centre line

This file contains details of the stations and legs, and any flags associated
with them.

.err - loop closure statistics (%age errors, etc)

This file contains statistics about each traverse in the survey which is part
of a loop. It includes various statistics for each traverse, such as the
percentage error per leg. You should study this information to determine if any
parts of the survey are of lower quality or contain gross errors. 

Error Messages

There are a number of error messages that you may get when processing data.
Most of these are self explanatory, and will be caused by such problems as
typing mistakes, or by your survey data not being attached to fixed points (in
this situation, Survex will list some of the stations that are not connected).

Along with the error message, the filename and line number of the offending
line will be printed (or the filename for errors such as `file not found'). The
format of the filename and line number is that used by gcc, so if your editor
can parse errors from gcc, you should be able to set it to allow you to jump to
the file and line of each error.

Cavern will stop after more than 50 errors. This usually indicates something
like the incorrect data order being specified. Deluging the user with error
messages makes the actual problem less clear.

aven

Name

aven -- sophisticated cave viewer for Unix and MS Windows

Synopsis

aven [--survey=SURVEY] [--print] {.3d file}

Description

Aven displays processed cave surveys in a window and allows you to manipulate
the view.

Note that there is no perspective in the view. This means that it is impossible
to tell which way round a cave is rotating, or whether you are viewing
something from behind, or in front. So if you think the direction of rotation
in wrong, or changes as you watch, this is just your brain being confused, not
a bug!

Mouse Control

The best way to move the cave is with the mouse. We suggest you try each of
these out after reading this section to get a feel for how they work.

If you hold down the right button then the cave is dragged when you move the
mouse.

If you hold down the left button, then the cave is rotated if you move left or
right, and zoomed if you move up and down. If you hold down Ctrl while dragging
with the left mouse button, then the cave rotates and tilts at the same time
instead.

If your mouse has a middle button then holding it down and moving the mouse up
and down tilts the cave. Moving the mouse left and right has no effect.

And if you have a scrollwheel, this can be used to zoom in/out.

By default the mouse moves the cave, but if you press Ctrl-R, then the mouse
will move the viewpoint instead (i.e. everything will go in the opposite
direction). Apparently this feels more natural to some people.

Keyboard Control

P and L select Plan and eLevation respectively. Changing between plan to
elevation is animated to help you see where you are and how things relate. This
animation is automatically disabled on slow machines to avoid user frustration.

Comma ', and Slash / tilt up and down respectively. Tilt goes 180 degrees from
plan view to a view from directly below (upside down plan).

Space toggles automatic rotation about a vertical axis on and off. The speed of
rotation for this, and animated transitions between plan and elevation, is
controlled by Z and X.

Crosses and/or labels can be displayed at survey stations. Ctrl-X toggles
crosses and Ctrl-N station names. Ctrl-L toggles the display of survey legs.

Delete is useful if you get lost - it resets the scale, position, and rotation
speed, so that the cave returns to the centre of the screen. There are also
keyboard controls to use instead of the mouse - Shift helps here as it
accelerates all movements:

Z, X : Faster/Slower Rotation
R: Reverse direction of rotation
Enter, Space: Start and stop auto-rotation
Ctrl-Cursor Left, Ctrl-Cursor Right: Rotate cave one step clockwise/anti-clockwise (also: C, V)
Ctrl-Cursor Up , Ctrl-Cursor Down: Higher/Lower Viewpoint (also: ' , /)
] , [: Zoom in/Out
U, D: Set view to Up/Down
N, S, E, W: Set view to North, South, East, West
Delete: Reset to default scale, rotation rate, etc
P, L: Plan, Elevation
Cursor Left, Cursor Right: Pan survey Left/Right (on screen)
Cursor Up, Cursor Down: Pan survey Up/Down (on screen)
Ctrl-N: Toggle display of station names
Ctrl-X: Toggle display of crosses at stations
Ctrl-L: Toggle display of survey legs
Ctrl-F: Toggle display of surface legs
Ctrl-G: Toggle display of grid
Ctrl-B: Toggle display of bounding box
O: Toggle display of non-overlapping/all names
Ctrl-R: reverse sense of controls
Shift: accelerates all movement keys

A little experimentation should give a better understanding of how this works.

There is an auto-resizing scale bar along the bottom of the screen which varies
in length as you zoom in or out. In the lower right corner is a compass pointer
showing which way is North, and a clino pointer showing the angle of tilt. And
in the upper right is a colour key showing the correspondence between colour
and depth (by default - you can also colour by date or by error).

Options

-p, --print

    Print the specified file and exit.

-s, --survey=SURVEY

    Only load the sub-survey 'SURVEY'.

3dtopos

Name

3dtopos -- produce a .pos file from a .3d file

Synopsis

3dtopos [options] {.3d file} [.pos file]

Description

3dtopos takes a .3d file and produces a .pos file which contains a list of all
the stations with coordinates (ordered x,y,z [East, North, Up]) and complete
names.

The stations are sorted such that numbers occur in the correct order (so ``2''
before ``10''). 3dtopos even sorts numbers with a prefix and/or suffix, so
you'd get:

040.sv8
040.sv8a
040.sv8b
040.sv8c
040.sv9
040.sv10
040.sv11
40_entrance_tag
40b_entrance_tag

You can also export .pos files from aven in versions 1.2.19 and later.

cad3d

Name

cad3d -- convert a Survex .3d file into formats which can be read by CAD and
drawing packages

Synopsis

cad3d [options] {.3d file} [output file]

Description

Cad3d can currently output DXF, Skencil, or SVG files for import into CAD
packages. It can also produce Compass .plt files, which are primarily intended
for importing into Carto, but can also be used with Compass itself.

diffpos

Name

diffpos -- compare the contents of two .3d files

Synopsis

diffpos {.3d file} {.3d file} [threshold]

Description

Diffpos reports stations which are in one file but not the other, and also
stations which have moved by more than a specified threshold distance in X, Y,
or Z. The threshold distance is given in metres and defaults to 0.01m if not
specified.

For backward compatibility diffpos will also read the .pos files produced by
earlier versions of cavern, by 3dtopos, or by aven's export feature (requires
1.2.19 or later).

extend

Name

extend -- produce an extended elevation from a .3d file

Synopsis

extend [--survey=SURVEY] [--specfile=ESPEC_FILE] [--show-breaks]
{INPUT_3D_FILE} [OUTPUT_3D_FILE]

Description

    Note: The extend program can also work on Compass .plt (as can aven and any
    other Survex program which reads .3d files).

If no specfile is given, extend starts with the highest station marked as an
entrance which has at least one underground survey leg attached to it. If there
are no such stations, the highest deadend station in the survey (or the highest
station if there are no deadends) is used. Extend puts the first station on the
left, then folds each leg out individually to the right, breaking loops
arbitrarily (usually at junctions).

If the output filename is not specified, extend bases the output filename on
the input filename, but ending "_extend.3d". For example, extend deep_pit.3d
produces an extended elevation called deep_pit_extend.3d.

If you pass --show-breaks then a leg flagged as "surface survey" will be added
between each point at which a loop has been broken - this can be very useful
for visualising the result in aven.

This approach suffices for simple caves or sections of cave, but for more
complicated situations human intervention is required. More complex sections of
cave can be handled with a specfile giving directions to switch the direction
of extension between left and right, to explicitly specify the start station,
or to break the extension at particular stations or legs.

The specfile is in a format similar to cavern's data format:

;This is a comment

; start the elevation at station entrance.a
*start entrance.a  ;this is a comment after a command

; start extending leftwards from station half-way-down.5
*eleft half-way-down.5

; change direction of extension at further-down.8
*eswap further-down.8

; extend right from further-down.junction, but only for
; the leg joining it to very-deep.1, other legs continuing
; as before
*eright further-down.junction  very-deep.1

; break the survey at station side-loop.4
*break side-loop.4

; break survey at station side-loop.junction but only
; for leg going to complex-loop.2
*break side-loop.junction complex-loop.2

This approach requires some trial and error, but gives useful results for many
caves. The most complex systems would benefit from an interactive interface to
select and view the breaks and switches of direction.

sorterr

Name

sorterr -- re-sort .err file by various criteria

Synopsis

sorterr [options] {.err file} [how many]

Description

Sorterr re-sorts a .err file by the specified criterion (or by the error ratio
by default). Output is sent to stdout, or if --replace is specified the input
file is replaced with the sorted version. By default all entries in the file
are included - if a second parameter is given then only the top entries after
sorting are returned.

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Survex data files

Survey data is entered in the form of text files. You can use any text editor
you like for this, so long as it has the capability of writing a plain ASCII
text file. The data format is very flexible; unlike some other cave surveying
software, Survex does not require survey legs to be rearranged to suit the
computer, and the ordering of instrument readings on each line is fully
specifiable. So you can enter your data much as it appears on the survey notes,
which is important in reducing the opportunities for transcription errors.

Also all the special characters are user-definable - for example, the
separators can be spaces and tabs, or commas (e.g. when exporting from a
spreadsheet), etc; the decimal point can be a slash (for clarity), a comma (as
used in continental Europe), or anything else you care to choose. This
flexibility means that it should be possible to read in data from almost any
sort of survey data file without much work.

Survex places no restrictions on you in terms of the ordering of survey legs.
You can enter or process data in any order and Survex will read it all in
before determining how it is connected. You can also use the hierarchical
naming so that you do not need to worry about using the same station name
twice.

The usual arrangement is to have one file which lists all the others that are
included (e.g., 161.svx). Then cavern 161 will process all your data. To just
process a section use the filename for that section, e.g. cavern dtime will
process the dreamtime file/section of Kaninchenhöhle. To help you out, if all
legs in a survey are connected to one another but the survey has no fixed
points, cavern will 'invent' a fixed point and print a warning message to this
effect.

It is up to you what data you put in which files. You can have one file per
trip, or per area of the cave, or just one file for the whole cave if you like.
On a large survey project it makes sense to group related surveys in the same
file or directory.

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Readings

Blank lines (i.e. lines consisting solely of BLANK characters) are ignored. The
last line in the file need not be terminated by an end of line character. All
fields on a line must be separated by at least one BLANK character. An OMIT
character (default '-') indicates that a field is unused. If the field is not
optional, then an error is given.

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Survey Station Names

Survex has a powerful system for naming stations. It uses a hierarchy of survey
names, similar to the nested folders your computer stores files in. So point 6
in the entrance survey of Kaninchenhöhle (cave number 161) is referred to as:
161.entrance.6

This seems a natural way to refer to station names. It also means that it is
very easy to include more levels, for example if you want to plot all the caves
in the area you just list them all in another file, specifying a new prefix. So
to group 3 nearby caves on the Loser Plateau you would use a file like this:

*begin Loser
*include 161
*include 2YrGest
*include 145
*end Loser

The entrance series point mentioned above would now be referred to as:
Loser.161.entrance.6

You do not have to use this system at all, and can just give all stations
unique identifiers if you like:

1, 2, 3, 4, 5, ... 1381, 1382

or

AA06, AA07, P34, ZZ6, etc.

Station and survey names may contain any alphanumeric characters and
additionally any characters in NAMES (default `_' and `-'). Alphabetic
characters may be forced to upper or lower case by using the *case command.
Station names may be any length - if you want to only treat the first few
characters as significant you can get cavern to truncate the names using the
*truncate command.

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Anonymous Stations

Survex supports the concept of anonymous survey stations. That is survey
stations without a name. Each time an anonymous station name is used it
represents a different point. Currently three types of anonymous station are
supported, referred to by one, two or three separator characters - with the
default separator of '.', that means '.', '..', and '...' are anonymous
stations. Their meanings are:

Single separator ('.' by default)

    An anonymous non-wall point at the end of an implicit splay.

Double separator ('..' by default)

    An anoymous wall point at the end of an implicit splay.

Triple separator ('...' by default)

    an anoymous point with no implicit flags on the leg (intended for cases
    like a disto leg along a continuing passage).

You can map '-' to '..' (for compatibility with data from pocket topo) using
the command:

*alias station - ..

Support for anonymous stations and for '*alias station - ..' was added in
Survex 1.2.7.

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Numeric fields

[<MINUS>|<PLUS>] <integer part> [ <DECIMAL> [ <decimal fraction> ] ]

or [<MINUS>|<PLUS>] <DECIMAL> <dec fraction>

i.e. optional PLUS or MINUS sign in front, with optional DECIMAL character
(default '.'), which may be embedded, leading or trailing. No spaces are
allowed between the various elements.

All of these are valid examples: +47, 23, -22, +4.5, 1.3, -0.7, +.15, .4, -.05

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Accuracy

Accuracy assessments may be provided or defaulted for any survey leg. These
determine the distribution of loop closure errors over the legs in the loop.
See *SD for more information.

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Cavern Commands

Commands in .svx files are introduced by an asterisk (by default - this can be
changed using the set command).

The commands are documented in a common format:

  • Command Name

  • Syntax

  • Example

  • Validity

  • Description

  • Caveats

  • See Also

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ALIAS

Syntax

    *alias station <alias> [<target>]

Example

    *begin parsons_nose
    *alias station - ..
    1 2 12.21 073 -12
    2 -  4.33 011 +02
    2 -  1.64 180 +03
    2 3  6.77 098 -04
    *end parsons_nose

Description

    *alias allows you to map a station name which appears in the survey data to
    a different name internally. At present, you can only create an alias of
    '-' to '..', which is intended to support the pocket topo style notation of
    '-' being a splay to an anonymous point on the cave wall. And you can
    unalias '-' with '*alias station -'.

    Aliases are scoped by *begin/*end blocks - when a *end is reached, the
    aliases in force at the corresponding begin are restored.

    *alias was added in Survex 1.2.7.

See Also

    *begin, *end

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BEGIN

Syntax

    *begin [<survey>]

Example

    *begin littlebit
    1 2 10.23 106 -02
    2 3  1.56 092 +10
    *end littlebit

    ; length of leg across shaft estimated
    *begin
    *sd tape 2 metres
    9 10 6.   031 -07
    *end

Description

    *begin stores the current values of the current settings such as instrument
    calibration, data format, and so on. These stored values are restored after
    the corresponding *end. If a survey name is given, this is used inside the
    *begin/*end block, and the corresponding *end should have the same survey
    name. *begin/*end blocks may be nested to indefinite depth.

See Also

    *end, *prefix

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CALIBRATE

Syntax

    *calibrate <quantity list> <zero error> [<scale>]

    *calibrate <quantity list> <zero error> <units> [<scale>]

    *calibrate default

Example

    *calibrate tape +0.3

Description

    *calibrate is used to specify instrument calibrations, via a zero error and
    a scale factor. By default, the zero error is 0.0 and the scale factor 1.0
    for all quantities.

    <quantity> is one of TAPE|COMPASS|CLINO|COUNTER|DEPTH|DECLINATION|X|Y|Z

    Several quantities can be given in <quantity list> - the specified
    calibration will be applied to each of them.

    You need to be careful about the sign of the ZeroError. Survex follows the
    convention used with scientific instruments - the ZeroError is what the
    instrument reads when measuring a reading which should be zero. So for
    example, if your tape measure has the end missing, and you are using the
    30cm mark to take all measurements from, then a zero distance would be
    measured as 30cm and you would correct this with:

    *CALIBRATE tape +0.3

    If you tape was too long, starting at -20cm (it does happen!) then you can
    correct it with:

    *CALIBRATE tape -0.2

    Note: ZeroError is irrelevant for Topofil counters and depth gauges since
    pairs of readings are subtracted.

    In the first form in the synopsis above, the zero error is measured by the
    instrument itself (e.g. reading off the number where a truncated tape now
    ends) and any scale factor specified applies to it, like so:

    Value = ( Reading - ZeroError ) * Scale (Scale defaults to 1.0)

    In the second form above (supported since Survex 1.2.21), the zero error
    has been measured externally (e.g. measuring how much too long your tape is
    with a ruler) - the units of the zero error are explicitly specified and
    any scale factor isn't applied to it:

    Value = ( Reading * Scale ) - ZeroError (Scale defaults to 1.0)

    If the scale factor is 1.0, then the two forms are equivalent, though they
    still allow you to differentiate between how the zero error has been
    determined.

    With older Survex versions, you would specify the magnetic declination
    (difference between True North and Magnetic North) by using *calibrate
    declination to set an explicit value (with no scale factor allowed). Since
    Survex 1.2.22, it's recommended to instead use the new *declination command
    instead - see the documentation of that command for more details.

See Also

    *declination, *units

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CASE

Syntax

    *case preserve|toupper|tolower

Example

    *begin bobsbit
    ; Bob insists on using case sensitive station names
    *case preserve
    1 2   10.23 106 -02
    2 2a   1.56 092 +10
    2 2A   3.12 034 +02
    2 3    8.64 239 -01
    *end bobsbit

Description

    *case determines how the case of letters in survey names is handled. By
    default all names are forced to lower case (which gives a case insensitive
    match, but you can tell cavern to force to upper case, or leave the case as
    is (in which case '2a' and '2A' will be regarded as different).

See Also

    *truncate

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COPYRIGHT

Syntax

    *copyright <date> <text>

Example

    *begin littlebit
    *copyright 1983 CUCC
    1 2 10.23 106 -02
    2 3  1.56 092 +10
    *end littlebit

Validity

    valid at the start of a *begin/*end block.

Description

    *copyright allows the copyright information to be stored in a way that can
    be automatically collated.

See Also

    *begin

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CS

Syntax

    *cs [out] <coordinate system>

Example

    *cs UTM60S
    *fix beehive 313800 5427953 20

    ; Output in the coordinate system used in the Totes Gebirge in Austria
    *cs out custom "+proj=tmerc +lat_0=0 +lon_0=13d20 +k=1 +x_0=0 +y_0=-5200000 +ellps=bessel +towgs84=577.326,90.129,463.919,5.137,1.474,5.297,2.4232"

Description

    *cs allows the coordinate systems used for fixed points and for processed
    survey data to be specified.

    *cs was added in Survex 1.2.14, but handling of fixed points specified with
    latitude and longitude didn't work until 1.2.21. And *fix with standard
    deviations specified also didn't work until 1.2.21.

    The currently supported coordinate systems are:

    CUSTOM followed by a PROJ4 string (like in the example above).

    EPSG: followed by a positive integer code. EPSG codes cover most coordinate
    systems in use, and PROJ supports many of these. The website https://
    epsg.io/ is a useful resource for finding the EPSG code you want. Supported
    since Survex 1.2.15.

    ESRI: followed by a positive integer code. ESRI codes are used by ArcGIS to
    specify coordinate systems (in a similar way to EPSG codes), and PROJ
    supports many of them. Supported since Survex 1.2.15.

    EUR79Z30 for UTM zone 30, EUR79 datum. Supported since Survex 1.2.15.

    IJTSK for the modified version of the Czechoslovak S-JTSK system where the
    axes point East and North. Supported since Survex 1.2.15.

    IJTSK03 for a variant of IJTSK. Supported since Survex 1.2.15.

    JTSK for the Czechoslovak S-JTSK system. The axes on this point West and
    South, so it's not support as an output coordinate system. Supported since
    Survex 1.2.16.

    JTSK03 for a variant of JTSK. Supported since Survex 1.2.16.

    LONG-LAT for longitude/latitude. The WGS84 datum is assumed. Supported
    since Survex 1.2.15.

    OSGB: followed by a two letter code for the UK Ordnance Survey National
    Grid. The first letter should be 'H', 'N', 'O', 'S' or 'T'; the second any
    letter except 'I'. Supported since Survex 1.2.15.

    S-MERC for the "Web Mercator" spherical mercator projection, used by online
    map sites like OpenStreetMap, Google maps, Bing maps, etc. Supported since
    Survex 1.2.15.

    UTM followed by a zone number (1-60), optionally followed by "N" or "S"
    (default is North). The WGS84 datum is assumed.

    By default, Survex works in an unspecified coordinate system (and this was
    the only option before *cs was added). However, it's useful for coordinate
    system which the processed survey data is in to be specified if you want to
    use the processed data in ways which required knowing the coordinate system
    (such as exporting a list of entrances for use in a GPS). You can now do
    this by using "*cs out".

    It is also useful to be able to take coordinates for fixed points in
    whatever coordinate system you receive them in and put them directly into
    Survex, rather than having to convert with an external tool. For example,
    you may have your GPS set to show coordinates in UTM with the WGS84 datum,
    even though you want the processed data to be in some local coordinate
    system. And someone else may provide GPS coordinates in yet another
    coordinate system. You just need to set the appropriate coordinate system
    with "*cs" before each group of "*fix" commands in a particular coordinate
    system.

    If you're going to make use of "*cs", then the coordinate system must be
    specified for everything, so a coordinate system must be in effect for all
    "*fix" commands, and you must set the output coordinate system before any
    points are fixed.

    Also, if "*cs" is in use, then you can't omit the coordinates in a "*fix"
    command, and a fixed point won't be invented if none exists.

    If you use "*cs out" more than once, the second and subsequent commands are
    silently ignored - this makes it possible to combine two datasets with
    different "*cs out" settings without having to modify either of them.

    Something to be aware of with "*cs" is that altitudes are currently assumed
    to be "height above the ellipsoid", whereas GPS units typically give you
    "height above sea level", or more accurately "height above a particular
    geoid". This is something we're looking at how best to address, but you
    shouldn't need to worry about it if your fixed points are in the same
    coordinate system as your output, or if they all use the same ellipsoid.
    For a more detailed discussion of this, please see: http://expo.survex.com/
    handbook/survey/coord.htm

See Also

    *fix

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DATA

Syntax

    *data <style> <ordering>

Example

    *data normal from to compass tape clino

    *data normal station ignoreall newline compass tape clino

Description

    <style> = DEFAULT|NORMAL|DIVING|CARTESIAN|TOPOFIL|CYLPOLAR|NOSURVEY|PASSAGE

    <ordering> = ordered list of instruments - which are valid depends on the
    style.

    In Survex 1.0.2 and later, TOPOFIL is simply a synonym for NORMAL, left in
    to allow older data to be processed without modification. Use the name
    NORMAL by preference.

    There are two variants of each style - interleaved and non-interleaved.
    Non-interleaved is "one line per leg", interleaved has a line for the data
    shared between two legs (e.g. STATION=FROM/TO, DEPTH=FROMDEPTH/TODEPTH,
    COUNT=FROMCOUNT/TOCOUNT). Note that not all interleavable readings have to
    be interleaved - for example:

    *data diving station newline fromdepth compass tape todepth

    In addition, interleaved data can have a DIRECTION reading, which can be
    "F" for a foresight or "B" for a backsight.

    In NORMAL, DIVING, and CYLPOLAR data styles, TAPE may be replaced by
    FROMCOUNT/TOCOUNT (or COUNT in interleaved data) to allow processing of
    surveys performed with a Topofil instead of a tape.

    DEFAULT

        Select the default data style and ordering (NORMAL style, ordering:
        from to tape compass clino).

    NORMAL

        The usual tape/compass/clino centreline survey. For non-interleaved
        data the allowed readings are: FROM TO TAPE COMPASS CLINO BACKCOMPASS
        BACKCLINO; for interleaved data the allowed readings are: STATION
        DIRECTION TAPE COMPASS CLINO BACKCOMPASS BACKCLINO. The CLINO/BACKCLINO
        reading is not required - if it's not given, the vertical standard
        deviation is taken to be proportional to the tape measurement.
        Alternatively, individual clino readings can be given as OMIT (default
        "-") which allows for data where only some clino readings are missing.
        E.g.:

        *data normal from to compass clino tape
        1 2 172 -03 12.61

        *data normal station newline direction tape compass clino
        1
         F 12.61 172 -03
        2

        *data normal from to compass clino fromcount tocount
        1 2 172 -03 11532 11873

        *data normal station count newline direction compass clino
        1 11532
         F 172 -03
        2 11873

    DIVING

        An underwater survey where the vertical information is from a diver's
        depth gauge. This style can also be also used for an above-water survey
        where the altitude is measured with an altimeter. DEPTH is defined as
        the altitude (Z) so increases upwards by default. So for a diver's
        depth gauge, you'll need to use *CALIBRATE with a negative scale factor
        (e.g. *calibrate depth 0 -1).

        For non-interleaved data the allowed readings are: FROM TO TAPE COMPASS
        CLINO BACKCOMPASS BACKCLINO FROMDEPTH TODEPTH DEPTHCHANGE (the vertical
        can be given as readings at each station, (FROMDEPTH/TODEPTH) or as a
        change along the leg (DEPTHCHANGE)).

        Survex 1.2.20 and later allow an optional CLINO and/or BACKCLINO
        reading in DIVING style. At present these extra readings are checked
        for syntactic validity, but are otherwise ignored. The intention is
        that a future version will check them against the other readings to
        flag up likely blunders, and average with the slope data from the depth
        gauge and tape reading.

        For interleaved data the allowed readings are: STATION DIRECTION TAPE
        COMPASS BACKCOMPASS DEPTH DEPTHCHANGE. (the vertical change can be
        given as a reading at the station (DEPTH) or as a change along the leg
        (DEPTHCHANGE)).

        *data diving from to tape compass fromdepth todepth
        1 2 14.7 250 -20.7 -22.4

        *data diving station depth newline tape compass
        1 -20.7
         14.7 250
        2 -22.4

        *data diving from to tape compass depthchange
        1 2 14.7 250 -1.7

    CARTESIAN

        Cartesian data style allows you to specify the (x,y,z) changes between
        stations. It's useful for digitising surveys where the original survey
        data has been lost and all that's available is a drawn up version.

        *data cartesian from to northing easting altitude
        1 2 16.1 20.4 8.7

        *data cartesian station newline northing easting altitude
        1
         16.1 20.4 8.7
        2

         

            Note: Cartesian data are relative to true North not magnetic North
            (i.e. they are unaffected by *calibrate declination).

    CYLPOLAR

        A CYLPOLAR style survey is very similar to a diving survey, except that
        the tape is always measured horizontally rather than along the slope of
        the leg.

        *data cypolar from to tape compass fromdepth todepth
        1 2 9.45 311 -13.3 -19.0

        *data cylpolar station depth newline tape compass
        1 -13.3
         9.45 311
        2 -19.0

        *data cylpolar from to tape compass depthchange
        1 2 9.45 311 -5.7

    NOSURVEY

        A NOSURVEY survey doesn't have any measurements - it merely indicates
        that there is line of sight between the pairs of stations.

        *data nosurvey from to
        1 7
        5 7
        9 11

        *data nosurvey station
        1
        7
        5

        *data nosurvey station
        9
        11

    PASSAGE

        This survey style defines a 3D "tube" modelling a passage in the cave.
        The tube uses the survey stations listed in the order listed. It's
        permitted to use survey stations which aren't directly linked by the
        centre-line survey. This can be useful - sometimes the centreline will
        step sideways or up/down to allow a better sight for the next leg and
        you can ignore the extra station. You can also define tubes along
        unsurveyed passages, akin to "nosurvey" legs in the centreline data.

        This means that you need to split off side passages into seperate
        tubes, and hence separate sections of passage data, starting with a new
        *data command.

        Simple example of how to use this data style (note the use of ignoreall
        to allow a free-form text description to be given):

        *data passage station left right up down ignoreall
        1  0.1 2.3 8.0 1.4  Sticking out point on left wall
        2  0.0 1.9 9.0 0.5  Point on left wall
        3  1.0 0.7 9.0 0.8  Highest point of boulder

    IGNORE skips a field (it may be used any number of times), and IGNOREALL
    may be used last to ignore the rest of the data line.

    LENGTH is a synonym for TAPE; BEARING for COMPASS; GRADIENT for CLINO;
    COUNT for COUNTER.

    The units of each quantity may be set with the UNITS command.

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DATE

Syntax

    *date <year>[.<month>[.<day>]][-<year>[.<month>[.<day>]]]

Example

    *date 2001

    *date 2000.10

    *date 1987.07.27

    *date 1985.08.12-1985.08.13

Validity

    valid at the start of a *begin/*end block.

Description

    *date specifies the date that the survey was done. A range of dates can be
    specified (useful for overnight or multi-day surveying trips).

See Also

    *begin, *instrument, *team

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DECLINATION

Syntax

    *declination <auto> <x> <y> <z>

    *declination <declination> <units>

Description

    The *declination command is the modern way to specify magnetic declinations
    in Survex. Prior to 1.2.22, *calibrate declination was used instead. If you
    use a mixture of *calibrate declination and *declination, they interact in
    the natural way - whichever was set most recently is used for each compass
    reading (taking into account survey scope). We don't generally recommend
    mixing the two, but it's useful to understand how they interact if you want
    to combine datasets using the old and new commands, and perhaps if you have
    a large existing dataset and want to migrate it without having to change
    everything at once.

    Magnetic declination is the difference between Magnetic North and True
    North. It varies both with location and over time. Compass bearings are
    measured relative to Magnetic North - adding the magnetic declination gives
    bearings relative to True North.

    If you have specified the output coordinate system (using *cs out) then you
    can use *declination auto (and we recommend that you do). This is supported
    since Survex 1.2.21 and automatically calculates magnetic declinations
    based on the IGRF (International Geomagnetic Reference Field) model for the
    specified date of each survey and at the specified representative location
    (given in the current input coordinate system, as set with *cs). Survex
    1.2.27 and later also automatically correct for grid convergence (the
    difference between Grid North and True North) when *declination auto is in
    use, based on the same specified representative location.

    You might wonder why Survex needs a representative location instead of
    calculating the magnetic declination and grid convergence for the actual
    position of each survey station. The reason is that we need to adjust the
    compass bearings before we can solve the network to find survey station
    locations. Both magnetic declination and grid convergence don't generally
    vary significantly over the area of a typical cave system - if you are
    mapping a very large cave system, or caves over a wide area, or are working
    close to a magnetic pole or where the output coordinate system is rather
    distorted, then you can specify *declination auto several times with
    different locations - the one currently in effect is used for each survey
    leg.

    Generally it's best to specify a suitable output coordinate system, and use
    *declination auto so Survex corrects for magnetic declination and grid
    convergence for you. Then Aven knows how to translate coordinates to allow
    export to formats such as GPX and KML, and to overlay terrain data.

    If you don't specify an output coordinate system, but fix one or more
    points then Survex works implicitly in the coordinate system your fixed
    points were specified in. This mode of operation is provided for
    compatibility with datasets from before support for explicit coordinate
    systems was added to Survex - it's much better to specify the output
    coordinate system as above. But if you have a survey of a cave which isn't
    connected to any known fixed points then you'll need to handle it this way,
    either fixing an entrance to some arbitrary coordinates (probably (0,0,0))
    or letting Survex pick a station as the origin. If the survey was all done
    in a short enough period of time that the magentic declination won't have
    changed significantly, you can just ignore it and Grid North in the
    implicit coordinate system will be Magnetic North at the time of the
    survey. If you want to correct for magnetic declination, you can't use
    *declination auto because the IGRF model needs the real world coordinates,
    but you can specify literal declination values for each survey using
    *declination <declination> <units>. Then Grid North in the implicit
    coordinate system is True North.

    Note that the value specified uses the conventional sign for magnetic
    declination, unlike the old *calibrate declination which needed a value
    with the opposite sign (because *calibrate specifies a zero error), so take
    care when updating old data, or if you're used to the semantics of
    *calibrate declination.

See Also

    *calibrate

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DEFAULT

Syntax

    *default <settings list>|all

Description

    The valid settings are CALIBRATE, DATA, and UNITS.

    *default restores defaults for given settings. This command is deprecated -
    you should instead use: *calibrate default, *data default, *units default.

See Also

    *calibrate, *data, *units

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END

Syntax

    *end [<survey>]

Validity

    valid for closing a block started by *begin in the same file.

Description

    Closes a block started by *begin.

See Also

    *begin

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ENTRANCE

Syntax

    *entrance <station>

Example

    *entrance P163

Description

    *entrance sets the entrance flag for a station. This information is used by
    aven to allow entrances to be highlighted.

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EQUATE

Syntax

    *equate <station> <station>...

Example

    *equate chosspot.1 triassic.27

Description

    *equate specifies that the station names in the list refer to the same
    physical survey station. An error is given if there is only one station
    listed.

See Also

    *infer equates

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EXPORT

Syntax

    *export <station>...

Example

    *export 1 6 17

Validity

    valid at the start of a *begin/*end block.

Description

    *export marks the stations named as referable to from the enclosing survey.
    To be able to refer to a station from a survey several levels above, it
    must be exported from each enclosing survey.

See Also

    *begin, *infer exports

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FIX

Syntax

    *fix <station> [reference] [ <x> <y> <z> [ <x std err> <y std err> <z std
    err> [ <cov(x,y)> <cov(y,z)> <cov(z,x)> ] ] ]

Example

    *fix entrance.0 32768 86723 1760

    *fix KT114_96 reference 36670.37 83317.43 1903.97

Description

    *fix fixes the position of <station> at the given coordinates. If you
    haven't specified the coordinate system with "*cs", you can omit the
    position and it will default to (0,0,0). The standard errors default to
    zero (fix station exactly). cavern will give an error if you attempt to fix
    the same survey station twice at different coordinates, or a warning if you
    fix it twice with matching coordinates.

    You can also specify just one standard error (in which case it is assumed
    equal in X, Y, and Z) or two (in which case the first is taken as the
    standard error in X and Y, and the second as the standard error in Z).

    If you have covariances for the fix, you can also specify these - the order
    is cov(x,y) cov(y,z) cov(z,x).

    You can fix as many stations as you like - just use a *fix command for each
    one. Cavern will check that all stations are connected to at least one
    fixed point so that co-ordinates can be calculated for all stations.

    By default cavern will warn about stations which have been FIX-ed but not
    used otherwise. This is unhelpful if you want to include a standard file of
    benchmarks, some of which won't be used. In this sort of situation, specify
    "REFERENCE" after the station name in the FIX command to suppress this
    warning for a particular station.

        Note: X is Easting, Y is Northing, and Z is altitude. This convention
        was chosen since on a map, the horizontal (X) axis is usually East, and
        the vertical axis (Y) North. The choice of altitude (rather than depth)
        for Z is taken from surface maps, and makes for less confusion when
        dealing with cave systems with more than one entrance. It also gives a
        right-handed set of axes.

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FLAGS

Syntax

    *flags <flags>

Example

    *flags duplicate not surface

Description

    *flags updates the current flag settings. Flags not mentioned retain their
    previous state. Valid flags are DUPLICATE, SPLAY, and SURFACE, and a flag
    may be preceded with NOT to turn it off.

    Survey legs marked SURFACE are hidden from plots by default, and not
    included in cave survey length calculations. Survey legs marked as
    DUPLICATE or SPLAY are also not included in cave survey length
    calculations; legs marked SPLAY are ignored by the extend program.
    DUPLICATE is intended for the case when if you have two different surveys
    along the same section of passage (for example to tie two surveys into a
    permanent survey station); SPLAY is intended for cases such as radial legs
    in a large chamber.

See Also

    *begin

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INCLUDE

Syntax

    *include <filename>

Example

    *include mission

    *include "the pits"

Description

    *include processes <filename> as if it were inserted at this place in the
    current file. (i.e. The current settings are carried into <filename>, and
    any alterations to settings in <filename> will be carried back again).
    There's one exception to this (for obscure historical reasons) which is
    that the survey prefix is restored upon return to the original file. Since
    *begin and *end nesting cannot cross files, this can only make a difference
    if you use the deprecated *prefix command.

    If <filename> contains spaces, it must be enclosed in quotes.

    An included file which does not have a complete path is resolved relative
    to the directory which the parent file is in (just as relative HTML links
    do). Cavern will try adding a .svx extension, and will also try translating
    "\" to "/". And as a last resort, it will try a lower case version of the
    filename (so if you use Unix and someone sends you a DOS/Windows dataset
    with mismatched case, unzip it with "unzip -L" and UNIX cavern will process
    it).

    The depth to which you can nest include files may be limited by the
    operating system you use. Usually the limit is fairly high (>30), but if
    you want to be able to process your dataset with Survex on any supported
    platform, it would be prudent not to go overboard with nested include
    files.

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INFER

Syntax

    *infer plumbs on|off

    *infer equates on|off

    *infer exports on|off

Description

    "*infer plumbs on" tells cavern to interpret gradients of +/- 90 degrees as
    UP/DOWN (so it will not apply the clino correction to them). This is useful
    when the data has not been converted to have UP and DOWN in it.

    "*infer equates on" tells cavern to interpret a leg with a tape reading of
    zero as a *equate. this prevents tape corrections being applied to them.

    "*infer exports on" is necessary when you have a dataset which is partly
    annotated with *export. It tells cavern not to complain about missing
    *export commands in part of the dataset. Also stations which were used to
    join surveys are marked as exported in the 3d file.

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INSTRUMENT

Syntax

    *instrument <instrument> <identifier>

Example

    *instrument compass "CUCC 2"
    *instrument clino "CUCC 2"
    *instrument tape "CUCC Fisco Ranger open reel"

Validity

    valid at the start of a *begin/*end block.

Description

    *instrument specifies the particular instruments used to perform a survey.

See Also

    *begin, *date, *team

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PREFIX

Syntax

    *prefix <survey>

Example

    *prefix flapjack

Description

    *prefix sets the current survey.

Caveats

    *prefix is deprecated - you should use *begin and *end instead.

See Also

    *begin, *end

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REF

Syntax

    *ref <string>

Example

    *ref "survey folder 2007#12"

Validity

    valid at the start of a *begin/*end block.

Description

    *ref allows you to specify a reference. If the reference contains spaces,
    you must enclose it in double quotes. Survex doesn't try to interpret the
    reference in any way, so it's up to you how you use it - for example it
    could specify where the original survey notes can be found.

    *ref was added in Survex 1.2.23.

See Also

    *begin, *date, *instrument, *team

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REQUIRE

Syntax

    *require <version>

Example

    *require 0.98

Description

    *require checks that the version of cavern in use is at least <version> and
    stops with an error if not. So if your dataset requires a feature
    introduced in a particular version, you can add a *require command and
    users will know what version they need to upgrade to, rather than getting
    an error message and having to guess what the real problem is.

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SD

Syntax

    *sd <quantity list> <standard deviation>

Example

    *sd tape 0.15 metres

Description

    *sd sets the standard deviation of a measurement.

    <quantity> is one of (each group gives alternative names for the same
    quantity):

      □ TAPE, LENGTH

      □ BACKTAPE, BACKLENGTH (added in Survex 1.2.25)

      □ COMPASS, BEARING

      □ BACKCOMPASS, BACKBEARING

      □ CLINO, GRADIENT

      □ BACKCLINO, BACKGRADIENT

      □ COUNTER, COUNT

      □ DEPTH

      □ DECLINATION

      □ DX, EASTING

      □ DY, NORTHING

      □ DZ, ALTITUDE

      □ LEFT

      □ RIGHT

      □ UP, CEILING

      □ DOWN, FLOOR

      □ LEVEL

      □ PLUMB

      □ POSITION

    <standard deviation> must include units and thus is typically "0.05
    metres", or "0.02 degrees". See *units below for full list of valid units.

    To utilise this command fully you need to understand what a standard
    deviation is. It gives a value to the 'spread' of the errors in a
    measurement. Assuming that these are normally distributed we can say that
    95.44% of the actual lengths will fall within two standard deviations of
    the measured length. i.e. a tape SD of 0.25 metres means that the actual
    length of a tape measurement is within + or - 0.5 metres of the recorded
    value 95.44% of the time. So if the measurement is 7.34m then the actual
    length is very likely to be between 6.84m and 7.84m. This example
    corresponds to BCRA grade 3. Note that this is just one interpretation of
    the BCRA standard, taking the permitted error values as 2SD 95.44%
    confidence limits. If you want to take the readings as being some other
    limit (e.g. 1SD = 68.26%) then you will need to change the BCRA3 and BCRA5
    files accordingly. This issue is explored in more detail in various
    surveying articles.

See Also

    *units

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SET

Syntax

    *set <item> <character list>

Example

    *set blank x09x20
    *set decimal ,

    Note that you need to eliminate comma from being a blank before setting it
    as a decimal - otherwise the comma in "*set decimal ," is parsed as a
    blank, and you set decimal to not have any characters representing it.

Description

    *set sets the specified <item> to the character or characters given in
    <character list>. The example sets the decimal separator to be a comma.

    xAB means the character with hex value AB. Eg x20 is a space.

    The complete list of items that can be set, the defaults (in brackets), and
    the meaning of the item, is:

      □ BLANK (x09x20,) Separates fields

      □ COMMENT (;) Introduces comments

      □ DECIMAL (.) Decimal point character

      □ EOL (x0Ax0D) End of line character

      □ KEYWORD (*) Introduces keywords

      □ MINUS (-) Indicates negative number

      □ NAMES (_-) Non-alphanumeric chars permitted in station names (letters
        and numbers are always permitted).

      □ OMIT (-) Contents of field omitted (e.g. in plumbed legs)

      □ PLUS (+) Indicates positive number

      □ ROOT (\) Prefix in force at start of current file (use of ROOT is
        deprecated)

      □ SEPARATOR (.) Level separator in prefix hierarchy

    The special characters may not be alphanumeric.

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SOLVE

Syntax

    *solve

Example

    *include 1997data
    *solve
    *include 1998data

Description

    Distributes misclosures around any loops in the survey and fixes the
    positions of all existing stations. This command is intended for situations
    where you have some new surveys adding extensions to an already drawn-up
    survey which you wish to avoid completely redrawing. You can read in the
    old data, use *SOLVE to fix it, and then read in the new data. Then old
    stations will be in the same positions as they are in the existing drawn up
    survey, even if new loops have been formed by the extensions.

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TEAM

Syntax

    *team <person> <role>...

Example

    *team "Nick Proctor" compass clino tape
    *team "Anthony Day" notes pictures tape

Validity

    valid at the start of a *begin/*end block.

Description

    *team specifies the people involved in a survey and what role they filled
    during that trip.

See Also

    *begin, *date, *instrument

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TITLE

Syntax

    *title <title>

Example

    *title Dreamtime

    *title "Mission Impossible"

Description

    *title allows you to set the descriptive title for a survey. If the title
    contains spaces, you need to enclose it in quotes (""). If there is no
    *title command, the title defaults to the survey name given in the *begin
    command.

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TRUNCATE

Syntax

    *truncate <length>|off

Description

    Station names may be of any length in Survex, but some other (mostly older)
    cave surveying software only regard the first few characters of a name as
    significant (e.g. "entran" and "entrance" might be treated as the same). To
    facilitate using data imported from such a package Survex allows you to
    truncate names to whatever length you want (but by default truncation is
    off).

    Figures for the number of characters which are significant in various
    software packages: Compass currently has a limit of 12, CMAP has a limit of
    6, Smaps 4 had a limit of 8, Surveyor87/8 used 8. Survex itself used 8 per
    prefix level up to version 0.41, and 12 per prefix level up to 0.73 (more
    recent versions removed this rather archaic restriction).

See Also

    *case

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UNITS

Syntax

    *units <quantity list> [<factor>] <unit>

    *units default

Example

    *units tape metres

    *units compass backcompass clino backclino grads

    *units dx dy dz 1000 metres ; data given as kilometres

    *units left right up down feet

Description

    <quantity> is one of the following (grouped entries are just alternative
    names for the same thing): TAPE/LENGTH, BACKTAPE/BACKLENGTH (added in
    Survex 1.2.25), COMPASS/BEARING, BACKCOMPASS/BACKBEARING, CLINO/GRADIENT,
    BACKCLINO/BACKGRADIENT, COUNTER/COUNT, DEPTH, DECLINATION, DX/EASTING, DY/
    NORTHING, DZ/ALTITUDE, LEFT, RIGHT, UP/CEILING, DOWN/FLOOR

    Changes current units of all the quantities listed to [<factor>] <unit>.
    Note that quantities can be expressed either as the instrument (e.g.
    COMPASS) or the measurement (e.g. BEARING).

    <factor> allows you to easy specify situations such as measuring distance
    with a diving line knotted every 10cm (*units distance 0.1 metres). If
    <factor> is omitted it defaults to 1.0. If specified, it must be non-zero.

    Valid units for listed quantities are:

    TAPE/LENGTH, BACKTAPE/BACKLENGTH, COUNTER/COUNT, DEPTH, DX/EASTING, DY/
    NORTHING, DZ/ALTITUDE in YARDS|FEET|METRIC|METRES|METERS (default: METRES)

    CLINO/GRADIENT, BACKCLINO/BACKGRADIENT in DEG|DEGREES|GRADS|MILS|PERCENT|
    PERCENTAGE (default: DEGREES)

    COMPASS/BEARING, BACKCOMPASS/BACKBEARING, DECLINATION in DEG|DEGREES|GRADS|
    MILS|MINUTES (default: DEGREES)

    (360 degrees = 400 grads (also known as Mils))

See Also

    *calibrate

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Contents of .svx files: How do I?

Here is some example Survex data (a very small cave numbered 1623/163):

2 1 26.60 222  17.5
2 3 10.85 014   7
2 4  7.89 254 -11
4 5  2.98  - DOWN
5 6  9.29 271 -28.5

You can vary the data ordering. The default is:

from-station to-station tape compass clino

This data demonstrates a number of useful features of Survex:

Legs can be measured either way round, which allows the use of techniques like
"leap-frogging" (which is where legs alternate forwards and backwards).

Also notice that there is a spur in the survey (2 to 3). You do not need to
specify this specially.

Survex places few restrictions on station naming (see "Survey Station Names" in
the previous section), so you can number the stations as they were in the
original survey notes. Although not apparent from this example, there is no
requirement for each leg to connect to an existing station. Survex can accept
data in any order, and will check for connectedness once all the data has been
read in.

Each survey is also likely to have other information associated with it, such
as instrument calibrations, etc. This has been omitted from this example to
keep things simple.

Most caves will take more than just one survey trip to map. Commonly the
numbering in each survey will begin at 1, so we need to be able to tell apart
stations with the same number in different surveys.

To accomplish this, Survex has a very flexible system of hierarchical prefixes.
All you need do is give each survey a unique name or number, and enter the data
like so:

*begin 163
*export 1
2 1 26.60 222  17.5
2 3 10.85 014   7
2 4  7.89 254 -11
4 5  2.98  - DOWN
5 6  9.29 271 -28.5
*end 163

Survex will name the stations by attaching the current prefix. In this case,
the stations will be named 163.1, 163.2, etc.

We have a convention with the CUCC Austria data that the entrance survey
station of a cave is named P<cave number>, P163 in this case. We can accomplish
this like so:

*equate P163 163.1
*entrance P163
*begin 163
*export 1
2 1 26.60 222  17.5
2 3 10.85 014   7
2 4  7.89 254 -11
4 5  2.98  - DOWN
5 6  9.29 271 -28.5
*end 163

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Specify surface survey data

Say you have 2 underground surveys and 2 surface ones with 2 fixed reference
points. You want to mark the surface surveys so that their length isn't
included in length statistics, and so that Aven knows to display them
differently. To do this you mark surface data with the "surface" flag - this is
set with "*flags surface" like so:

; fixed reference points
*fix fix_a 12345 56789 1234
*fix fix_b 23456 67890 1111

; surface data (enclosed in *begin ... *end to stop the *flags command
; from "leaking" out)
*begin
*flags surface
*include surface1
*include surface2
*end

; underground data
*include cave1
*include cave2

You might also have a survey which starts on the surface and heads into a cave.
This can be easily handled too - here's an example which goes in one entrance,
through the cave, and out of another entrance:

*begin BtoC
*title "161b to 161c"
*date 1990.08.06 ; trip 1990-161c-3 in 1990 logbook

*begin
*flags surface
02    01      3.09   249    -08.5
02    03      4.13   252.5  -26
*end

04    03      6.00   020    +37
04    05      3.07   329    -31
06    05      2.67   203    -40.5
06    07      2.20   014    +04
07    08      2.98   032    +04
08    09      2.73   063.5  +21
09    10     12.35   059    +15

*begin
*flags surface
11    10      4.20   221.5  -11.5
11    12      5.05   215    +03.5
11    13      6.14   205    +12.5
13    14     15.40   221    -14
*end

*end BtoC

Note that to avoid needless complication, Survex regards each leg as being
either "surface" or "not surface" - if a leg spans the boundary you'll have to
call it one or the other. It's good surveying practice to deliberately put a
station at the surface/underground interface (typically the highest closed
contour or drip line) so this generally isn't an onerous restriction.

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Specify the ordering and type of data

The *DATA command is used to specify the data style, and the order in which the
readings are given.

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Deal with Plumbs or Legs Across Static Water

Plumbed legs should be given using 'UP' or 'DOWN' in place of the clino reading
and a dash (or a different specified 'OMIT' character) in place of the compass
reading. This distinguishes them from legs measured with a compass and clino.
Here's an example:

1 2 21.54 - UP
3 2 7.36 017 +17
3 4 1.62 091 +08
5 4 10.38 - DOWN

U/D or +V/-V may be used instead of UP/DOWN; the check is not case sensitive.

Legs surveyed across the surface of a static body of water where no clino
reading is taken (since the surface of the water can be assumed to be flat) can
be indicated by using LEVEL in place of a clino reading. This prevents the
clino correction being applied. Here's an example:

1 2 11.37 190 -12
3 2  7.36 017 LEVEL
3 4  1.62 091 LEVEL

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Specify a BCRA grade

The *SD command can be used to specify the standard deviations of the various
measurements (tape, compass, clino, etc). Examples files are supplied which
define BCRA Grade 3 and BCRA Grade 5 using a number of *sd commands. You can
use these by simply including them at the relevant point, as follows:

*begin somewhere
; This survey is only grade 3
*include grade3
2 1 26.60 222  17.5
2 3 10.85 014   7
; etc
*end somewhere

The default values for the standard deviations are those for BCRA grade 5. Note
that it is good practice to keep the *include Grade3 within *Begin and *End
commands otherwise it will apply to following survey data, which may not be
what you intended.

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Specify different accuracy for a leg

For example, suppose the tape on the plumbed leg in this survey is suspected of
being less accurate than the rest of the survey because the length was obtained
by measuring the length of the rope used to rig the pitch. We can set a higher
sd for this one measurement and use a *begin/*end block to make sure this
setting only applies to the one leg:

2 1 26.60 222  17.5
2 3 10.85 014   7
2 4  7.89 254 -11
*begin
; tape measurement was taken from the rope length
*sd tape 0.5 metres
4 5  34.50 - DOWN
*end
5 6  9.29 271 -28.5

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Enter Repeated Readings

If your survey data contains multiple versions of each leg (for example,
pockettopo produces such data), then provided these are adjacent to one another
Survex 1.2.17 and later will automatically average these and treat them as a
single leg.

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Enter Radiolocation Data

This is done by using the *SD command to specify the appropriate errors for the
radiolocation `survey leg' so that the loop closure algorithm knows how to
distribute errors if it forms part of a loop.

The best approach for a radiolocation where the underground station is
vertically below the surface station is to represent it as a plumbed leg,
giving suitable SDs for the length and plumb angle. The horizontal positioning
of this is generally quite accurate, but the vertical positioning may be much
less well known. E.g: we have a radiolocation of about 50m depth +/- 20m and
horizontal accuracy of +/- 8m. Over 50m the +/-8m is equivalent to an angle of
9 degrees, so that is the expected plumb error. 20m is the expected error in
the length. To get the equivalent SD we assume that 99.74% of readings will be
within 3 standard deviations of the error value. Thus we divide the expected
errors by 3 to get the SD we should specify:

*begin
*sd length 6.67 metres
*sd plumb 3 degrees
surface underground 50 - down
*end

We wrap the radiolocation leg in a *begin/*end block to make sure that the
special *sd settings only apply to this one leg.

For more information on the expected errors from radiolocations see Compass
Points Issue 10, available online at http://www.chaos.org.uk/survex/cp/CP10/
CPoint10.htm

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Enter Diving Data

Surveys made underwater using a diver's depth gauge can be processed - use the
*Data command to specify that the following data is of this type.

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Enter Theodolite data

Theodolite data with turned angles is not yet explicitly catered for, so for
now you will need to convert it into equivalent legs in another style - normal
or cylpolar are likely to be the best choices.

If there is no vertical info in your theodolite data then you should use the
cylpolar style and use *sd command to specify very low accuracy (high SD) in
the depth so that the points will move in the vertical plane as required if the
end points are fixed or the survey is part of a loop.

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General: How do I?

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Create a new survey

You simply create a text file containing the relevant survey data, using a text
editor, and save it with a suitable name with a .svx extension. The easiest way
is to look at some of the example data and use that as a template. Nearly all
surveys will need a bit of basic info as well as the survey data itself: e.g.
the date (*date), comments about where, what cave, a name for the survey (using
*begin and *end), instrument error corrections etc. Here is a typical survey
file:

All the lines starting with ';' are comments, which are ignored by Survex. You
can also see the use of 'DOWN' for plumbs, and *calibrate tape for dealing with
a tape length error (in this case the end of the tape had fallen off so
measurements were made from the 20cm point).

*equate chaos.1 triassic.pt3.8
*equate chaos.2 triassic.pt3.9

*begin chaos
*title "Bottomless Pit of Eternal Chaos to Redemption pitch"
*date 1996.07.11
*team "Nick Proctor" compass clino tape
*team "Anthony Day" notes pictures tape
*instrument compass "CUCC 2"
*instrument clino "CUCC 2"
;Calibration: Cairn-Rock 071 072 071,  -22 -22 -22
;       Rock-Cairn 252 251 252,  +21 +21 +21
;Calibration at 161d entrance from cairn nr entrance to
;prominent rock edge lower down. This is different from
;calibration used for thighs survey of 5 July 1996

*export 1 2

;Tape is 20cm too short
*calibrate tape +0.2

1 2 9.48 208 +08
2 3 9.30 179 -23
3 4 2.17 057 +09
5 4 10.13 263 +78
5 6 2.10 171 -73
7 6 7.93 291 +75
*begin
*calibrate tape 0
8 7 35.64 262 +86 ;true length measured for this leg
*end
8 9 24.90 - DOWN
10 9 8.61 031 -43
10 11 2.53 008 -34
11 12 2.70 286 -20
13 12 5.36 135 +23
14 13 1.52 119 -12
15 14 2.00 036 +13
16 15 2.10 103 +12
17 16 1.40 068 -07
17 18 1.53 285 -42
19 18 5.20 057 -36
19 20 2.41 161 -67
20 21 27.47 - DOWN
21 22 9.30 192 -29
*end chaos

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Join surveys together

Once you have more than one survey you need to specify how they link together.
To do this use *export to make the stations to be joined accessible in the
enclosing survey, then *equate in the enclosing survey to join them together.

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Organise my surveys

This is actually a large subject. There are many ways you can organise your
data using Survex. Take a look at the example dataset for some ideas of ways to
go about it.

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Fixed Points (Control Points)

The *fix command is used to specify fixed points (also know as control points).
See the description of this command in the "Cavern Commands" section of this
manual.

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More than one survey per trip

Suppose you have two separate bits of surveying which were done on the same
trip. So the calibration details, etc. are the same for both. But you want to
give a different survey name to the two sections. This is easily achieved like
so:

*begin
*calibrate compass 1.0
*calibrate clino 0.5
*begin altroute
; first survey
*end altroute
*begin faraway
; second survey
*end faraway
*end

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Add surface topography

Survex 1.2.18 added support for loading terrain data and rendering it as a
transparent surface. Currently the main documentation for this is maintained as
a wiki page as this allows us to update it between releases.

We recommend using this new code in preference, but previously the simplest
approach was to generate a .svx file with the surface mesh in and display it
with the survey data.

It is possible to generate a mesh or contours overlaying your area by various
means. NASA have made 1 arc-second (approximately 30m) terrain data available
for the USA for some years, with only 3 arc-second data available for other
countries. However, starting in 2014 they're gradually making 1 arc-second data
available for more countries.

If you want a better resolution that this, reading heights from the contours on
a map is one approach. It's laborious, but feasible for a small area.

Details of several methods are given in the BCRA Cave Surveying Group magazine
Compass Points issue 11, available online at http://www.chaos.org.uk/survex/cp/
CP11/CPoint11.htm#Art_5

If you're using another program to generate a .svx file for the surface mesh,
it's best to use the NOSURVEY data style. Simply fix all the grid intersections
at the correct coordinates and height, and put legs between them using the
NOSURVEY style. Here's a grid of 4 squares and 9 intersections:

*fix 00 000 000 1070
*fix 01 000 100 1089
*fix 02 000 200 1093

*fix 10 100 000 1062
*fix 11 100 100 1080
*fix 12 100 200 1089

*fix 20 200 000 1050
*fix 21 200 100 1065
*fix 22 200 200 1077

*data nosurvey station

00
01
02

10
11
12

20
21
22

00
10
20

01
11
21

02
12
22

This is far simpler than trying to create fake tape/compass/clino legs of the
right length for each line in the mesh. It's also very fast to process with
cavern.

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Overlay a grid

Aven is able to display a grid, but this functionality isn't currently
available in printouts. You can achieve a similar effect for now by creating a
.svx file where the survey legs form a grid.

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Import data from other programs

Survex supports a number of features to help with importing existing data. You
can specify the ordering of items on a line using *Data (see Survex Keywords
above), and you can specify the characters used to mean different things using
*Set (see Survex Keywords above).

The Ignore and Ignoreall options to the *Data command are often particularly
useful, e.g. if you have a dataset with LRUD info or comments on the ends of
lines.

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Changing Meanings of Characters

e.g. if you have some data with station names containing the characters '?' and
'+' (which are not permitted in a name by default) then the command:

*SET NAMES ?+

specifies that question marks and plus signs are permitted in station names.
A-Z, a-z, and 0-9 are always permitted. '_' and '-' are also permitted by
default, but aren't in this example.

If your data uses a comma ',' instead of a decimal point, then you use

*SET DECIMAL ,

to specify that ',' is now the decimal separator instead of '.'.

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Export data from Survex

See Rosetta Stal in the Related Tools section of the Survex web site. This is a
utility written by Taco van Ieperen and Gary Petrie. Note though that this only
supports a subset of the svx format, and only work on Microsoft Windows. The
Survex support is limited and doesn't understand the more recently added
commands.

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See errors and warnings that have gone off the screen

When you run Survex it will process the specified survey data files in order,
reporting any warnings and errors. If there are no errors, the output files are
written and various statistics about the survey are displayed. If there are a
lot of warnings or errors, they can scroll off the screen and it's not always
possible to scroll back to read them.

The easiest way to see all the text is to use cavern --log to redirect output
to a .log file, which you can then inspect with a text editor.

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Create an Extended Elevation

Use the Extend program. This takes .3d files and 'flattens' them. See 'Extend'
for details.

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Working with Larry Fish's Compass

Survex can read Compass survey data - both raw data (.DAT and .MAK files) and
processed survey data (.PLT and .PLF files). You can even use *include
compassfile.dat in a .svx file and it'll work!

One point to note (this tripped us up!): station names in DAT files are case
sensitive and so Survex reads DAT files with the equivalent of *case preserve.
The default in SVX files is *case lower. So this won't work:

*fix CE1 0 0 0
*include datfilewhichusesCE1.dat

Because the CE1 in the *fix is actually interpreted as ce1. This is what you
have to do:

*begin
*case preserve
*fix CE1 0 0 0
*include datfilewhichusesCE1.dat
*end

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Mailing List

The best way to contact the authors and other Survex users is the Survex
mailing list - for details visit: https://survex.com/maillist.html

We'd be delighted to hear how you get on with Survex and welcome comments and
suggestions for improvements.

And we'd love you to contribute your skills to help make Survex even better.
Point out areas of the documentation which could be made clearer, or sections
which are missing entirely. Download test releases, try them out, and let us
know if you find problems or have suggestions for improvements. If there's no
translation to your language, you could provide one. Or if you're a developer, 
"Say it with code". There's plenty to do, so feel free to join in.

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Future Developments

Now that Survex has reached version 1.0, we are continuing progress towards
version 2, in a series of steps, evolving out of Survex 1.0. The GUI framework
is being based on aven, with the printer drivers and other utility programs
being pulled in and integrated into the menus.

Aven is built on wxWidgets, which means that it can easily support Unix,
Microsoft Windows, and Mac OS X.

More information on our plans is on the web site.

