Differences

This shows you the differences between two versions of the page.

--- tips [2019/10/05 22:28] – XTherion - Finding drawing where extents are large brucemutton
+++ tips [2019/12/07 09:56] – Making a subset of the cave take its altitude colours from a larger part of the cave tarquinwj
@@ Line 45: / Line 45: @@
   * Always check the "object setup area" on right side and "status line" on bottom of it. You may find there any necessary information with help to create object with correct parameters and in correct place.
   * If you press the "Escape" key you leave the "Insert Mode" and switch to "Select mode". The "Select mode" works in two steps - **select** - after first click you may check the parameters of object in "Status line" or "File commands" or "object setup area" and - **move** - after second click you may move with object.
-  * If you add line object, you may start to insert new line simple by pressing of Ctrl+L keys, you don't need to escape from "Inserting mode" first.
+  * To add a line object, you may start to insert new line simple by pressing of Ctrl+L keys, you don't need to escape from "Inserting mode" first.
   * Always check the small yellow tick on first point of line object. It shows the FREE space side of line. It means you should draw walls in counterclockwise direction, the blocks in clockwise direction, pit or chimney in counterclockwise direction, etc. If you made a mistake there is "reverse" option in "Line commands" section.
@@ Line 52: / Line 52: @@
 An easier way to locate any drawing objects is to open the Objects window on the top right-hand side of the XTherion interface, and click on one of the objects listed.
 Except for scraps, and areas, most objects will be selected and the drawing area will be panned to show the object mid-screen.\\
+For example, clicking on object 4 below, selects it and brigs it to the centre of the drawing area.
+{{tips:xtherion_extents_find__objects.png?300}}
+If you are repeatedly creating th2 files with large blank extents around the drawings and images, then it may be because of spurious drawing lines made accidentally when navigating during data collection with PocketTopo, TopoDroid, SexyTopo or the likes.  It may also be because of inappropriate parameters used (chosen by you or the application developer) to export data from these applications to Therion.\\
+If drawings and export\imports are well posed, then your drawing area extents should not be much larger than your actual drawing.\\
+You can manually or automatically tweak the drawing area that is viewable for a particular file if you scroll down to the Drawing Area window near the bottom of the right-hand side of XTherion, and make adjustments there.
-If you are repeatedly creating th2 files with large blank extents around the drawings and images, then it may be because of spurious drawing lines made accidentally when navigating during data collection with PocketTopo, TopoDroid, SexyTopo or the likes.  It may also be because of inappropriate parameters used to export data from these applications to Therion.
 ====Checking and erasing empty objects in .th2 files====
@@ Line 192: / Line 196: @@
     join scrap1 scrap2 [-count <number of passage (not line) joins for Therion to look for>]
-Note that this works using passages defined by lines of "wall" type (even if their "-outline" is set to "none"). It does not join other types of line. It normally expects to find pairs of lines, one on each side of the passage. If there are multiple passages that need to be joined between pairs of scraps, you can normally use the "-count" option to say how many possible passage joins Therion should search for.
+The method can only join two scraps at a time.  Note that it only works using passages defined by lines of "wall" type (even if their "-outline" is set to "none"). It does not join other types of line. It normally expects to find pairs of lines, one on each side of the passage opening. If there are multiple places where the two scraps join, you can normally use the "-count" option to say how many possible passage joins Therion should search for in the two scraps.
 **Manual line by line**
-From time to time the semi-automatic way does not work, or you want more refined control.  Then you should join each line to the other line (usually, but not only walls) or to a point. Every point on a line has a mark according its sequence from beginning of line (yellow tick). The first one has mark 0, next one 1, etc., last one is mark "end". So the join command will be:\\
+From time to time the semi-automatic way does not work, or you want more refined control.  Then you should join each line to the other line (usually, but not only walls) or to a point. If you have several objects to join at one point, then unlike the scrap by scrap join above, you should use one join statement to join them all (see bottom of this topic).  Every point on a line has a mark according its sequence from beginning of line (yellow tick). The first one has mark 0, next one 1, etc., last one is mark "end". So the join command will be:\\
@@ Line 265: / Line 269: @@
 {{:tips:zig-zag_map.png?150|map}} {{:tips:zig-zag_extended.png?150|extended}}\\
 See also [[extend|Extended Elevations]] page for comprehensive extended elevation guidance.
+====Making a subset of the cave take its altitude colours from a larger part of the cave====
+When rendering a map (map-endmap), with "color map-fg altitude" enabled, the default automatic altitude colour bands take their highest and lowest values from the highest and lowest survey stations for the parts of the survey that are used in the rendering. It takes all the survey stations within the "cave" (ie. not in a "flags surface" section), from whichever surveys and subsurveys have some of their parts included in the map, and finds the highest and lowest station. This happens even if the highest and lowest stations within those surveys are not even rendered because they are not included in a scrap.
+When you want to render a subset of that cave, such as a map showing only the entrance series of a cave, you might want to have the colours match the colours that were used in the overall map, so that the parts of the cave are recognisable. One way is to use an [[examples#colour_palette_scales_-_lookups|altitude lookup]].
+Another approach, which allows Therion to continue using automatic altitude colours, is to include the highest and lowest surveys/subsurveys in your map, and then use symbol-hide to hide those surveys. If you don't know which part of the cave will be the highest or lowest, just include all of them, to be on the safe side.
+  map foo
+    subsectionmap@subsection #the part you actually want to render
+    othersubsection #the survey containing the highest part of the cave
+    anothersubsection #the survey containing the lowest part of the cave
+  endmap
+Your layout would then include this:
+  color map-fg altitude
+  symbol-hide group centreline
+By hiding the centreline, you cause the unwanted surveys not to render at all, so the output acts like they were never included (it is cropped accordingly to show only the rendered part).
+If you need to include a centreline-only section of the cave in your rendering, then the same approach works, but it is a little more convoluted. Create a scrap in the highest and lowest parts of the cave. Those scraps should contain only a single station point. It doesn't have to be the highest or lowest station, since simply including any station causes all of them within that survey to be considered for the highest and lowest points. Give that station the "-visibility off" option. Include that scrap instead of including the survey itself. [Note, currently trying to work out how to remove the centreline markers only within the scrap where they are not needed, since this causes the selected survey to affect the rendering.]
 =====Map Layout=====