Therion is a system for high-quality cave maps. At the heart of this system is the therion language, that is a language to define through text files the graphic elements of cave maps, ie, points, lines, symbols, and so on.

The text files, written in the therion language, are processed by the therion program to generate the cave map in PDF format. This program relies on other program to process the survey data, cavern, and to produce the high-quality drawings, MetaPost, TeX, and pdfTeX [2] .

While it is easy to write and edit survey data file with any text editor, writing and editing drawing files is not easy at all, although it is actually possible. It is better to make use of a program with a graphical interface. One such program, xtherion, is distributed with therion. Any graphical interface, compatible with the terion language would fit the task. xtherion is written in Tcl/Tk, therefore it is necessary to have the Tcl/Tk interpreter to run it.

xtherion is not WYSIWYG (what you see is what you get), and this makes it less user-friendly. On the other hand the approach followed by therion, which keeps the data separated from their presentation (and/or final result), allows more freedom in the output, and makes the maintenance easier. For example, the closure of a loop, is easily taken into account since the data used to generate the map are always the original data (as opposed to data obtained as result of intermediate processing).

Make sure that the directory with therion and the programs it uses are included in the PATH. Windows user who have installed therion with the setup program, should have no problem here.

Linux users who have installed all the programs should have no problem, either. To check that the programs are accessible through the PATH type the command "which cavern mpost tex pdftex therion xtherion". If the program is found its full path is displayed. Otherwise the name of the program, with semicolon, is shown. Instead of pdftex you might have pdfetex. It is not necessary that xtherion is accessible through the PATH. It is possible to invoke it by specifying its path. If you want to find the program through the PATH, you can add the directory, that contains the program, to the PATH with the command "export PATH=$PATH:directory" (for the bash shell, for the others the command is slightly different; "echo $SHELL" tells you which shell you are using).

Now go into the directory of therion and type the command "xtherion" (or "./xtherion/xtherion" if you have not installed therion yet. A small window appears, telling you that xtherion is starting. And after a short while the xtherion window appears as in the figure below.

xtherion window has a menu bar with four menus: "File", "Edit", "Window" and "Help". A toolbar is underneath the menubar. There are two work areas (both empty and black at the moment): the upper one for the configuration file, the lower one for the output logs. A control panel is on the right, and a status bar on the bottom.

The "Help" menu has three submenus:

• "Control" opens a window with the summary of the commands (controls);
• "BAC calculator": a calculator for the percentage of alcohol in the blood (Blood Alcohol Calculator), the Metabolic Removal Rate (MRR) and how long you should wait before drawing the cave map (ETA, Estimated Time of Arrival);
• "About" displays the program version and the authors names.

As you might expect, this menu has submenus to create ("New") or open ("Open") a configuration file, save it ("Save") and close it ("Close"). There is also the submenu to compile the project, "Compile", and "Exit", to quit xtherion.

xtherion has several shortcuts, ie, keys or key-combinations that are equivalent to menus and commands. The most important is "F9" which compiles the project. Thus if you press "F9" is as if you select the menu "File | Compile".

The "Window" menu switches between the interactive mode of xtherion:

• "Text Editor": editor of text data files (centerline);
• "Map Editor": editor of drawing data files (scraps);
• "Compiler": the confguration file editor and project compiler. This is the mode in which xtherion starts.
• "Model Viewer": to view 3D models.

Each interactive mode has its menubar (with menus specific for each mode), its status bar (status messages specific for each mode), and control panel (with controls specific for each mode).

There are three menus to maximize the window, "Maximize", to bring it to normal size, "Normalize", and to toggle the position of the controls panel to the left or to the right, "Switch Panel".

Finally there is the submenu "KBD Encoding" to select the encoding of the keyboard. If anyone drops me a note about this, i put it here.

The toolbar of xtherion has been added with version 0.3.10. It has a few buttons for the most common actions: to create a new file, to open an existing one, to save and to close a file; there are buttons to switch among the xtherion modes, and a button to compile the project.

In the map editor mode, the toolbar has also buttons on the right for the most frequent graphical operations: zoom in and out; insertion of scraps, points, lines and areas; selection and deletion of the selected element.

The controls panel is, by default, on the right and contains several buttons with blue background, the controls. The number and type of controls depends on the interactive mode. The panel can be moved to the left with the menu "Window | Switch panels".

Each control can be open or closed: when it is open the informations of the control are show below the blue button. To open or close a control double click on the button.

xtherion window has a status bar on the bottom. The status bar display useful messages on the status on the program. Therefore get the habit to read its content.

Now try to switch the interactive mode by clicking on the proper menu. Notice how the buttons of the panel change. Notice that the name of the mode appears in the window title.

Select the submenus of "Help". You may also try out the "BAC calculator" ...

At the end go back to the "Compiler" mode.