Therion by examples

The advantage of a system like Therion to make and maintain the cave survey data are

the graphical data are digital: this favours the exchange of data, distribution of the drawing task, and team work;
"vectorization" of the drawing data, therefore without the ambiguities that might arise in printed maps or scanned bitmaps (raster data);
automatic map update as the survey grows, including new cave branches and loops (no need to redraw the map by hand);
more style uniformity when pieces of the cave map are composed in a single map: the data files contains only commands, while the presentation is specified in the configuration file
the possibility to create a database with map infos, where queries can be performed;
export of the survey data in various 3D model formats, for processing by other programs, such as GIS, and 3D visualization programs
configurability of the output maps that can be suited to the need at hand: publication, presentation, show, etc.

Therion features are

Therion is open source, distribuited under GPL licence;
the format of the input survey data is very close to that of survex [1] , although there are substantial differences;
it can import centerline data in the format of other programs: Survex "3d", Compass "plt", generic "xyz", and PocketTopo Therion export. PocketTopo import results in a "xvi" files including the sketches.
maps can be produced in the following formats: "pdf", "svg", "xhtml", "survex", "dxf", "esri53", "kml"
centerline and LRUD can be saved in Therion vector format "xvi", which can have also morphed background sketches.
it can produce maps in PDF format up to a size of about 5x5 m, or as atlas, collection of tile-pages;
it can generate the 3D model without the LRUD (left right up down) data, as it uses the informations of the drawings;
it can export the cave model in georefenced ESRI shape files, or as Loch files (for 3D visualization), as well as other formats (Compass "plt", Survex "3d", Toporobot "3dmf", "dxf", "vrml" and Google Earth "kml");
it can export data as SQL scripts that can be used to populate a database;
it can export summary lists of caves, surveys, continuation points. The following formats are supported: "html", "txt", "dbf";
a cave map is composed by drawing many little pieces (scraps) that are then pasted together to form the map(s), like a cave survey is made by composing many individual surveys.
there is no WYSIWYG (what you see is what you get) user interface for therion: the graphical interface xtherion is of great help in drawing the scraps, but is far from being WYSIWYG.
it supports several languages: english, czech, german, spanish, french, italian, portuguese, slovak, and russian.

Therion is developed by S. Mudrak and M. Budaj (with the help of others). The name "therion" comes from ancient greek and means "little animal". The official web site is http://therion.speleo.sk/ . There is some documentation on therion.

an introductory guide is on the web site http://www.infonegocio.com/tatel/therion_for_cavers.txt ; although unfinished it is nevertheless very useful [2] .
an article on Compass Point 33 (2004) [3] describes version 0.2.?, but is useful as overview and as introduction;
there is a wiki for therion (based on dokuwiki), which collects all the documentation, including FAQ, Tips and Tricks, examples, and Howtos. The wiki is downloadable as HTML pages at http://therion.speleo.sk/wiki/export/ . Furthermore, nightly snapshots of the Therion wiki are available for download as "unofficial user documentation".
the distribution contains a set of examples (subdirectory samples) that can be compiled and processed through a Tcl script to generate a browsable documenttaion of the samples;
the details of the language are documented in The Therion Book [4] , which is always included in the distribution;
finally, to know and extend therion (and xtherion) there is the source code, and the documentation about cavern, TeX, MetaPost, and pdfTeX, which are the programs used by therion.

Furthermore, general purpose graphics drawing programs can be used to make cave maps. They are however targeted to different customers that cavers, with more sofisticated needs from a graphical point of view, but without the management problems typical of cave maps.

cave illustrator http://www.caversdigest.com/software.htm
xara-X http://www.xara.com/products/xarax
Freehand http://www.adobe.com/products/freehand/
Canvas X http://www.acdamerica.com/

Tunnel is open source, is written in Java, and distribuited under GPL licence [5] . It is developed by J. Todd. It's a WYSIWYG program, but, once the individual pieces of the drawing are composed to form the map of the cave, these are no longer of any use. The input format of the centerline data e` exactly that of survex. So far it manages only the plan of the cave, and the section (normal and extended) is under development. The documentation is based on a wiki, and although incomplete, is growing. The interface is rather simple and it is possible to check the final outcome while drawing. From this poit of view it is a competitor of therion, although it has fewer functionalities.

Carto is open source and distributed under GPL, too. It is developed by R. Hartley [6] , but the development seems stopped at the spring 2005 (version 0.9.8). It is written in Java, uses Compass plot file (extension .plt) and takes in input images in PNG, GIF and JPEG format. It organizes the maps as projects (extension .cto). A project consists of a Compass .plt file, and files of "plan" type (for the plan) each with one or more cave segments. A segment is the scanned image of a survey sketch. The connection between images and centerline is obtanied relating points on the images with stations on the centerline. A segment has also a border which defines the portion of the scanned image that belongs to the segment. Segments are included, with suitable deformations, in the map ("plan") which can be exported as PNG file. Carto documentation is rather good: on the website there is a tutorial and FAQ. The manual is empty, however. It is also possible to browse the source code documentation. Overall , Carto is more a program to put together scanned images rather than a program to make cave map drawings.

Walls is not free software and is available only for Windows. It is written by D. Mckenzie of the Texas Speleological Society. The work is organized as projects (files with extension ".prj") and the output is in SVG format, which needs a SVG viewer to be seen (e.g. Adobe SVG viewer). A project is hierarchically organized under a root, and can contain survey data file and graphics SVG files. Walls is not a drawing editor: the map drawings must be made with a SVG editing program (e.g. Adobe Illustrator) using the SVG file of the centerline data, exported by Walls. There is practically no documentation, but Walls includes an introductory example and a more complex one which should help to learn how to use the program.

WinKarst was born in 1995, from karst, a program for the processing of centerline data under DOS, created in 1987 [7] [8] [9] . It has reached version 12.3 and is essentially a software for the processing of the centerline data, but it manages overlaying of DEM (digital elevation model) and SDTS (Spatial Data Transfer Standard, the USGS data format) files. It can import drawings and allows to register the imported image on the centerline, by fixing two points (which define the orientation and the scale). It can export bitmaps or DXF file.

Cave Illustrator is a plugin for Adobe Illustrator version 9 http://www.adobe.com/products/illustrator/ and is available only for Windows. It uses the Compass ".dat" files. It draws the shots as Illustrator artwork objects, that can then be edited by Illustrator. The station names are drawn as text objects. It is possible to select and manage graphically the stations and the shots. Plan and extended section can be drawn both on the same page, or on different pages. The plan can be rotated, i.e. the north can be oriented in a direction other than the vertical. I do not have direct experience of Cave Illustrator for two reasons: it is for Windows, and Illustrator is not freeware. However it seems to be an addon for Illustrator, to specifically handle the survey data, leaving to Illustrator the drawing.

Xara X is a program for graphical drawings [10] . It is very similar to Illustrator, and has a rich set of graphics functionalities. However it is a generic program, not specifically designed for the drawing and the menagement of cave maps. A large documentation about xarax is on the website http://www.xaraxone.com .

If we consider the trend of suite of programs, initiated as simple aids to the processing of the centerline data, we may notice that they have evolved with more and more additional functionalities:

2D and 3D display of cave data, with some sort of management of surface maps, digital terrain model (DTM), and integration of geogaphical data (GPS);
organization of the data, through custom databases, for the management of large cave system projects;

The possibility to include scanned images of the cave drawings, and automatically stretch them to fit the centerline is a first step towards the inclusion of cave drawing functionalities in the suite. From this point of view, therion, fits as a complement to the survex suite. Hades is expected to have scanned sketch inclusion and drawing features [11] .

Introduction