A point is the position on the cave map where therion draws cave symbols, labels, stations, etc.

Station points are special. They are very important because they allow to register the drawing according to the metric informations of the centerline of the survey.

To connect the drawing to the centerline it is necessary to insert station points (ie, points of type "station") in the scrap. Select the menu "Edit | Insert - point" and click with the left mouse button in the positions on the background image where the stations are. It is not necessary that the background image is drawn perfectly well. therion will take care to stretch it to fit the stations in the survey centerline (ie, their positions measured with the instruments).

When you are in "insert point" mode, the status bar displays a red "insert point" message. To check that you made no mistake, you can compile (menu "File | Compile", or key F9) and xtherion switches to the compiler window and compiles the project. If everything is fine, you can barely see the green "OK" message, and xtherion comes back to the map editor window.

In the "Points" control you can choose the type of the point(s) you are inserting. Once selected the type remains unchanged for all the points you insert, until you change it. Therefore it is convenient to insert points in group by the type.

Now insert a few station points and set to them the option "-name N" where N is the station name in the survey data file . As we said xtherion preserves the type of the last inserted point, therefore it is convenient to insert all the stations one after the other. Furthermore xtherion update the option "-name N" automatically at each insertion incrementing the value of N. Therefore, you need only to be careful and correct it when the station number changes in a different way.

There are many point types. Among them:

• centerline: station, section, extra;
• cave symbols: air, water, source, sink;
• geological symbols: anastomosis, breakdown, scallop, pillar, karren;
• speleothems: aragonite, pearl, crystal, disc, stalagmite, stalactite, soda straw, helictite, popcorn, column, moonmilk;
• other deposits: snow, ice, sand, block, rock, clay, calcite, pebbles, gypsym, guano;
• equipment: anchor, traverse, rope, ladder;
• passage ends: entrance, narrow-end, low-end, continuation;
• labels: label, remark, altitude, passage-height, station-name, date, height;
• others: archeo-material, paleo-material, camp, root, note.

Certain point types can be further detailed with a -subtype option:

• station can be temporary, painted, natural or fixed. If no subtype is specified it is temporary.
• air-draught can be summer, winter or undefined. If no subtype is specified it is undefined.
• water-flow can be premanent, intermittent or paleo. If no subtype is specified it is permanent.

The subtype can be written also together the type, separated by a semicolon. For example

  point 403 522 air-draught -subtype winter -orientation 234
  point 374 569 air-draught:winter -orientation 218

Label strings can be written in multiple languages. The tag >lang:XX<, where XX is the language country code, marks the start of a translation. For example

  point 400 200 label -text "Deep black<lang:it>Profondo nero"

The secific translation is selected according to the current layout export language. If there is no translation for the selected language, the default one (that before any lang tag) is used. If there is no default nothing is printed out.

Titles and other strings can have multiple translations, too. It is also possible to include right-to-left writings: the tag >r2l< starts a right-to-left section. The tag >l2r< ends it.

Points are shown in the canvas as blue dots. The last inserted point is always the selected point: it is displayed with a red circle around the blue dot. To change the selected point come out of the "insert point" mode (key "Esc" or menu "Edit | Select"), and click on the point you want to select.

To move a point after having selected it with the left mouse button, it is enough to drag it before releasing the button. To remove a point, select it and press Ctrl-D (or the menu "Edit | Delete").

If the point has an orientation (for example points of types "gradient" "water-flow", "air-draught", ...) this is displayed with a red arrow, that turns yellow when you grab it with the mouse to change the point orientation. By default the orientation is 0 (to the north, or vertical). To change the orientation of the point grab the arrow with the mouse and turn it (or write the value in degrees in the appropriate textbox of the "Points" control).

This option specifies the point alignment. It is useful for point features that must retain a certain orientation when the map is rotated (for example labels). The -align option takes as argument the type of the alignment: "top", "bottom", "left" etc..

It is possible to change the size of the point symbol with the option -scale. The default is "m" (normal). Other values are "s" (small), "xs" (very small), "l" (big), "xl" (very big).

For most of the point types it is possible to specify (option -clip) whether to clip the point symbol to the cave outline or not. Labels and station points canot be clipped.

The place option lets you define the layer where therion must place the point. It can have values bottom, default or top.

Each point can be hidden, that is notdisplayed on the map, with the option -visibility off (the default is "on"). Points can also be hidden with the symbol-hide point layout option, or if it in the context (-context option) of a hidden point type.

Certain point types must have a -text option. Points of type label must have a text (option -text) and can have an orientation (in the figure the label is at 45 degrees). The points of type survey-name have the option -text with the name of the station.

A few point types (altitude, height, passage-height, dimensions, data, extra) take a -value option. The points of type date must have a value (option -value or -dist) otherwise nothing is rendered in the output. The points of type dimension are not rendered graphically, but they store information on the dimensions of the cave passage, up and down if the scrap projection is plan; for example the option -value [2.6 1.5] denotes a dimension of 2.6 m up and 1.5 m down. Another example: point 237 312 date -dist "2008.01.31".

The points of type height must have a -value that can be positive (chimney) or negative (pit), and can have an optional question mark; for example -value [20? m]. The points of type passage-height must have a -value that specifies the height of the passage (positive number, eg, -value +4.5), or the depth of the floor or a pool (negative number), or the distance floor-ceiling (a number with no sign), or a pair of numbers (distances to the ceiling and to the floor, eg, -value [5.6 1.2]). A point of type altitude has a -value option that specifes the altitude with respect to the nearest station. To specify an absolute altitude use the keyword "fix", eg, -value [fix 2126].

The figures below show how the point symbols are drawn using the UIS symbols (which is the default). Symbols with other sets do not differ that much. To see all the symbols run therion with the option --print-symbols. This produces a xhtml file, symbols.xhtml, that can be viewed with a web browser (eg, firefox). Grey rows contain text symbols or labels, which are currently defined globally, independent of the symbol set. [M. Buday 20070310].

Some point types have also a subtype. The point air-draught can have subtype winter or summer to denote the different seasonal flow. The symbol is decorated with a star (winter) or a sun (summer). The point type water-flow can have subtype permanent (default), intermittent, and paleo. Points of type station can have subtype temporary (default), painted, natural, and fixed.