Therion is a complete platform which processes survey data and 
generates maps or 3D models of caves. This suite may be useful for 
professional or amateur cavers and researchers in geology or 
speleology fields. 

The package includes the following components:
- therion: the basic executable program that works as a command-line 
  compiler and processes input files, which are - including 2D maps - 
  in text format, to create files with 2D maps or 3D model. 2D maps 
  can be generated in PDF or SVG formats or other formats handled by 
  GIS platforms (DXF, ESRI, KML) or Aven (Survex format). 3D models 
  can be generated in the native format (handled by the component 
  Loch) or other formats (Compass, 3DMF, VRML, Survex, ecc.) handled 
  by appropriate viewers.  
- xtherion: the executable program that launches the GUI   (Graphical 
  User Interface). Xtherion works as text editor, map editor, and 
  compiler (instead of therion). This component is not essential: 
  output files can be generated by therion preparing the input files 
  with external programs as text or maps editors. 
- Loch: a 3D model viewer that supports high-resolution rendering to 
  file and stereo view using 3D-glasses. This component is not 
  essential: output 3D models can be displayed with other external 
  viewers.
- thbook.pdf: the Therion Book, it contains the documentation to use 
  Therion, generated with pdfTEX during the build process. It will be 
  installed in /usr/doc/therion-[VERSION]. This component is not 
  essential: a copy of the book (in basic size format) is also 
  available in the project homepage.
  
The build of the optional components is enabled by default. You can 
exclude one or more of them by passing to the script the respective 
environment variables:

- LOCH=no This disables the build of the native 3D viewer Loch. In 
          this case wxWidgets and VTK are not required.
- GUI=no  This disables the build of Xtherion.
- BOOK=no This disables the build of thbook.pdf.

WARNINGS

Note that the platform works only with some standards, interpreters or 
programs (like METAPOST, TEX, tcl/tk, ImageMagick, ecc.) that are 
available in a full installation of Slackware, and some extensions of 
these (like LCDF Typetools, Bwidget, and tkImg) that are available in 
Slackbuilds.org. Without these dependencies Therion fails during the 
package build (almost) or in runtime for some features (e.g. tkImg, 
that is not detected by the build process).

Since version 6.1.7, Therion no longer includes an internal {fmt}
library, so this library is a required dependency. In Slackware 15.0,
this library must be installed by the slackbuild available in
Slackbuilds.org whereas in Slackware current it must be installed
from the package released with the official current.

Since version 6.1.8, the build of LOCH fails if wxGTK3 is installed
instead of wxWidgets 3.2.2.1, so wxWidgets is strictly required. If
both wxGTK3 and wxWidgets are installed, the build process will use
wxWidgets, so these libraries can coexist. Other libraries based on
wxWidgets (like wxPython3 or wxPython4 for example) are not tested.

After the installation, a full and extended integrated behavior,
optimized with the custom configuration, requires to set or uncomment
appropriate values in the initialization files in /etc/therion.

Sample data can be downloaded from the project homepage. They can be
used to practice about Therion.

See the thbook.pdf for more information.