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<h2 id="tophead">CUCC Expedition Handbook - History of Survex</h2>
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<h1>History of Survex as of 1996</h1>
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<p align="center"><em>Cambridge Underground 1996, pp 63-6</em></p>
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<p>[This article was published in CU 1996, shortly after the site was put
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on the web. The text is reproduced without change.]
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<h2>History of Survex</h2>
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<p><b><i>by Wookey</i></b></center>
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<p>Back in 1988 CUCC used a programmable calculator to reduce survey data
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in Austria, and only on return to the UK did we have access to anything as
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advanced as real survey software. This was Sean Kelly's 'Surveyor '88'
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software, written for the "Below Belize" expedition. This was pretty good
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- you could give it data and it would do the sums, display them in
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windows, and print out the results, on multiple sheets if necessary. It
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didn't take us long to find a couple of serious bugs, but as Sean was
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still in Cambridge we could hassle him until he fixed them. However he
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wasn't really interested in developing it any further, and the software's
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deficiencies were beginning to become annoying (you couldn't use tabs to
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separate data items, or '+' on positive clino readings, and the graphics
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were very slow and uninterruptible, so if you accidentally pushed a button
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you were stuck until it finished displaying (in several minutes time for
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KH on a slow computer).
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<p>So, I started to produce a spec for some better software, and Olly
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Betts soon became interested and we worked together to decide what was
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needed. Now there was already other software available at the time, but
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the only other one that was any good which we knew of (SMAPS) was pretty
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expensive at $99. So we took the same route as others, and decided to
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write our own. The problem was that most authors had simply looked at
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their own projects, and knocked together something sufficient for that.
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Most of these had little or no loops processing as the authors didn't know
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the maths or how to translate that into algorithms. There seemed no point
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in repeating this short-sighted approach, so we determined to try and
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produce something that would be useful to others as well as ourselves.
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This meant it had to be versatile, and if we wanted it to be used it needed
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to be free too. The basic spec was:
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<ul>
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<li>Multiple computing platforms supported
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<li>Multiple languages supported
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<li>Data to be entered with as little change as possible from the original
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notes:<br>ie.
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<ul>
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<li>Free-form text entry
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<li>Data entry ordering/characters specifiable (eg. . , / or ,
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for decimal separator)
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<li>Proper mathematically-based network reduction for loops
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<li>Versatile naming conventions Connections made by either use of
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existing station names, or saying station X is the same as station Y
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</ul>
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<li>Scalable, so it would work on slow small computers as well as big fast
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ones.
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<li>No software-imposed limits (eg. number of stations, legs, loops)
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<li>Fast-as-possible cave display
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<li>Source availability so anyone can make changes or additions
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</ul>
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<p>Surveyor '88 had many of the above features, and followed basically the
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same design philosophy. We took the good ideas from that, and discarded
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the bad ones. We could have worked from the Surveyor '88 source but our
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multiple platforms requirement made that difficult as Surveyor '88 was
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written in Pascal, and Pascal compilers were not readily available for all
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machines. Thus we decided to write in C as it is a very portable
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language and produces fast software.
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<p>A Specification was duly written (which still comprises a large chunk
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of the documentation, unfortunately) and we started writing, with Olly
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quickly taking on nearly all the programming work. The first tangible result
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was the prototype for CaveRot which was written during the 1991 expo in
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BASIC and ARM code on an A3000.
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<p>A trip to the Surveyors' meeting at the 1991 Swiss Caving Conference
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showed us what was possible when we saw the Mac package 'Toporobot',
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which was very capable and impressive. We talked to its author Martin
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Heller, who was most encouraging, telling us that Toporobot was only ever
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intended for the Mac, and we should go away and write some decent software
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for all those other machines.
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<p>The bones took shape rapidly and Survex became the software of choice
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finally superseding Surveyor '88 during the 1992 expo. Since then it has
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grown to several hundred K of source, with versions for DOS, RISCOS &
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UNIX. A major development was the use of the GNU PC compiler DJGPP which
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removes the 640K memory limit imposed by DOS. This was necessary as
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<span lang=de>Kaninchenhöhle</span> quickly became sufficiently large
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& complex that the miserable 640K provided on a DOS PC simply wasn't
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enough memory to process it in.
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<p>Five years on [1996], Survex has become a powerful cave surveying tool with one
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of the most powerful data engines available. It lacks a great deal of
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fancy user interface features (help, menus etc.) that can be found on other
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good cave survey software packages, although the revolutionary
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mouse-controlled CaveRot interface remains unique.
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<p>A great deal of care has gone into designing the way that data is
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entered, stored and processed. The command structure is neat powerful and
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extensible. The network processing is done reasonably rigorously. It could be
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done more rigorously, but a great deal of extra memory would be required
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for little practical benefit.
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<p>A number of other groups are now using it - it is particularly popular
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in Brazil as the only survey software available in Portuguese. It has also
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been translated to French, German, Italian, Spanish, Catalan, and US
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English. Various other people have supplied add-ons such as an HTO
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converter by Bill Purvis (HTO is a standard for the interchange of cave
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survey data), and a program that combines Survex data, LRUD passage
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data, and surface data then outputs it all as a DXF file for input into a
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drafting package. This is being used by Chelsea Speleological Society in
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their survey of <span lang=cy>Ogof Draenen.</span> It is also being used for
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the OFD and Easegill re-surveys, and thus is the software of choice for the 3
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longest systems in the UK.
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<p><b>Distinguishing features:</b>
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<ul>
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<li>It's free!
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<li>Multi-platform (from lowly 8088 PCs to UNIX systems)
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<li>Powerful (in terms of survey complexity)
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<li>Versatile (in terms of input data)
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<li>Fast processing of survey data
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<li>Hi-speed mouse and/or keyboard controlled survey viewer
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<li>Good printer/plotter support.
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<li>Source code freely available
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<li>Multiple language support (English, US English, Portuguese, French,
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German, Catalan, Spanish, Italian)
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<li>PC version uses DPMI and so is compatible with Windows extended memory
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management.
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</ul>
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<p><b>Data processing:</b>
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<ul>
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<li>Survey complexity limited only by available memory (on a 386 or better
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PC you get up 128Mb of virtual disk memory as well as the memory in the
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machine)
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<li>Versatile system for hierarchical survey station naming, so station 36
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in Stomping in cave number 161 is referred to in full as
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'161.Stomping.36', but within 161 it is just 'Stomping.36', and within
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Stomping it is just '36'.
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<li>When specifying the data format you can use IGNORE and IGNOREALL to
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allow direct reading of basic data from many other survey software
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packages, e.g. Toporobot, CMAP, Compass, Karst, SMAPS(SEF), Survey,
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!Survey (batch). Also any lines it doesn t understand at all will simply be
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ignored.
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<li>Multiple caves can be processed just as easily as one
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<li>Data can be stored in single files, many files, or in directories, as
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you see fit. Files can be included for processing within other files.
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<li>Command files listing a set of Survex commands can be created for
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complex tasks
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<li>Surface topography can be included as contours or mesh
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<li>Separate treatment of plumbed and horizontal (water-surface) legs (not
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adjusted by clino adjustment)
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<li>Free-text input with user-definable symbols, so you can choose the
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separator, decimal point, command prefix etc. This aids import from other
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programs, spreadsheet data, foreign languages etc.
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<li>If no fixed points are given then the highest one is fixed at 0,0,0
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automatically
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<li>Network reduction by least squares. Standard errors calculated, and
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recorded for each leg in vertical & horizontal
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<li>The survey network is split at articulation points when doing network
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reduction, to increase speed and reduce memory requirements.
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<li>Omitted clino readings give a vertical SD of tape/sqrt(10). This
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basically means that clino-less data (eg. collected with a theodolite, or
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by pacing), will stretch vertically, if attached to other data, allowing
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for the fact that the height change is very unlikely to be more than the
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length of the leg.
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<li>Expected error/Standard deviations specifiable for all measurements
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<li>Suitable BCRA Grade files supplied to set appropriate standard
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deviations.
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<li>Diving-style data understood, ie. Depth readings instead of Clino.
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<li>Optional sequential loop closure, so new loops can leave old loops
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unaffected.
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<li>Output is binary (for speed) or ASCII (for people) 3d cave plot file,
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text co-ordinate data, summary info, and error details.
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<li>Summary statistics - Cave N/S, E/W, and Up/Down extents, total length,
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adjusted length, number of legs, stations, time taken to process.
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<li>BEGIN and END commands allow sections (usually surveys) to be defined,
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and changed settings will not affect other data.
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<li>Errors and warnings highlight the area of the line which Survex isn't
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happy about (where appropriate).
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<li>Warnings given for many common errors: The idea it to alert the user
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to possible cock-ups, but to still try and process the data if possible.
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<br>'Hanging' stations listed
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<br>Compass given on plumbed leg
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<br>Survey leg with same station at both ends - typo?
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<br>Tape negative, or adjustment makes reading negative
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<br>Compass reading not in range 0-360
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<br>Clino reading over 90 degrees
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<br>Length of tape measurement is less that change in depth (for diving
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data)
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<br>Same station fixed twice (Error if co-ordinates do not match)
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<li>There are also comprehensive messages given for syntactical errors.
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</ul>
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<p><b>Printer support:</b>
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<ul>
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<li>Multi-page printouts (for big plots on small printers)
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<li>8, 9 and 24 pin dot matrix (Epson, IBM Proprinter, and compatibles) -
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specifiable printer codes
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<li>PCL - i.e. all deskjets, laserjets and compatibles - specifiable
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resolution
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<li>Postscript - specifiable fonts and line widths
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<li>HPGL driver - for various pen plotters - can use centre or corner
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origin
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<li>Canon BJ series special driver to come
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<li>All drivers allow:
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<ul>
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<li>Any view printable - plan, elevation on any plane and angle of tilt.
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<li>specifiable scale
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<li>specifiable paper size
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</ul>
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<li>number of pages required, and arrangement (eg 3x2), is reported.
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<li>Any arbitrary list of pages can be printed.
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<li>Any of border, legs, station and labels can be printed/left out
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<li>Dotted borders and corner alignment marks are included for accurate
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cutting & assembly of multiple sheets
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<li>Names of processed surveys, and time of processing printed on all
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plots.
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</ul>
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<p><b>Graphics:</b>
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<ul>
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<li>DOS graphics support for VGA, EGA, CGA, Hercules, 8514a, et al
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<li>Acorn RISC OS at various resolutions
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<li>X-Windows support
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<li>Intuitive mouse-controlled cave control (zoom, pan and plan/elevation
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swap), with choice of mouse moving viewpoint or object
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<li>Automated rotation
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<li>Direction of view, scale & tilt indicators
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<li>Even extremely large areas (hundreds of kilometres across) can be
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smoothly viewed, but you can still zoom in to a few centimetres.
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<li>Constant rotation speed (so small caves on fast computers don't spin
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ridiculously fast)
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<li>Multiple data files can be read & displayed in different colours
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(eg. cave & surface colours)
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<li>Labels plotted so they don t overlap and can be read
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<li>Labels automatically removed while moving the plot
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<li>Completely flat caves (i.e. Extended Elevations) are automatically
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recognised and locked side-on
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</ul>
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<p><b>Other Utilities:</b>
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<ul>
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<li>DIFFPOS: utility for comparing two .pos files included
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<li>SVX2HTO and HTO2SVX: for converting from & to HTO data transfer
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format
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<li>EXTEND: for flattening the survey to create an extended elevation.
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<li>SVX2DXF: converter now included for moving cave plots into CAD or
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drawing packages in 3D.
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</ul>
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<p><b>So where next?</b>
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<p>The driving force of development is CUCC's surveying needs, and the
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requests of users. The time and effort required for producing a survey of
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a big system like <span lang=de>Kaninchenhöhle</span> means that we
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struggle to produce surveys containing each year's new finds. The reasons why
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the new bits cannot simply be added to the existing drawing are threefold
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<p>1) new bits go off the edge of the page
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<br>2) new loops mean that the rest of the survey bends
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<br>3) new additions often require redrawing of junctions or low-grade
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surveys
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<p>All of these can be often be bodged round for a year or two but sooner
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or later you have to re-draw the whole lot. In the case of the elevation
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it has become so complex that we are simply incapable of drawing anything
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that makes sense!
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<p>Doing the whole thing on computer would help in all of these areas. There
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is no 'edge of the paper'. Perfect alterations can be made without smear
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marks from rubbers. Adding the text so that it is all horizontal is easy. The
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hard bit is bending existing survey sections when the centreline they were
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originally drawn round has changed. Olly's 1991 computer project explored the
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mechanisms required to achieve this, working from original work by David
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McKenzie, and producing algorithms which could be applied to each vector or
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bitmap cave data. The computer needs to be told how the drawing relates to
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the centreline so that the whole lot can be stretched and rotated to fit.
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This a feature that will eventually be implemented in Survex.
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<p>In the meantime we have been looking at how to use existing LRUD (Left,
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Right, Up Down) data to produce an enhanced view with volume, rather than
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just a line survey. We concluded that the data as it stood was too
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'humanistic' to be sensibly interpreted by a computer. Such things as
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which side are left and right, what to do with all the '?' and '-' entries
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at junctions and on pitches, etc. are all problematic. Andy Atkinson worked
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out a compromise scheme where we give the computer some extra information
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about junctions, chambers, and changes from predominantly horizontal to
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vertical passage, as well as abandoning LRUD entirely for pitches and
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using NSEW (North, South, East, West) instead. This new format can be
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retro-fitted to existing data with the aid of the sketches in order to
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make it sufficient. Julian Todd's handy experience with a firm
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that writes CADCAM software gives him the tools and competence to write
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software that does all the hard sums, hidden line removal, and 3d-drawing
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relatively easily. Once this scheme is shown to be viable it is likely to
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become a fully-fledged part of Survex, giving excellent cave visualisation.
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<p>On a more mundane level work has been progressing towards fitting a
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graphical front-end to Survex so that it can become a native application
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in modern GUI Environments (Windows, RISCOS, X-Windows, MacOS,
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etc). The main barrier to this is working out sufficiently cross-platform
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ways of achieving it.
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<p>Finally there is a huge list of features people would like. Many of
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these require a more advanced format for the 3d files that Survex
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currently outputs. This has been largely worked out and is likely to hit
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the streets in the next version of Survex. This will allow the cave viewer
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to know lots of stuff about the cave, like which bit is which survey, and
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where the loops, junctions and entrances are, so that these things can be
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displayed on request.
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<p>SURVEX can be obtained from:
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<br>Wookey, 734 Newmarket Rd, Cambridge, CB5 8RS 01223 504881(H) 01223
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811679(W)
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<br>Mailto:wookey (at) aleph1.co.uk
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<br>Please send a formatted disc and a Stamped Self Addressed Envelope
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<br>You can also get it from the UK cavers archive site at
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ftp://chert.lmu.ac.uk/pub/chert/Survex by anonymous ftp. Also keep an eye
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out for a Survex Website in the near future.
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<p><em>[These days, get survex from <a href="https://survex.com/">https://survex.com/</a> ]</em>
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<p><hr>
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