I am just starting to try and draw up my first projected elevations in Therion (only 5 years into the project!). I have found that you cannot reproject an elevation from one bearing onto another (Therion only includes elevation maps containing scraps of the exact same bearing as the export statement). e.g. In my thconfig: export map -projection [elevation 180] -layout local -o ElevEW.pdf My scrap type is set to: elevation 180 If I don't declare the projection in my map, then the map is only included in the export when the bearings match between the export and the scrap. (180 degrees meaning the elevation is a projection looking due South, so the drawing represents a slice through the cave from East to West across the page from left to right. I am drawing the scrap using an extended elevation sketch from PocketTopo which is from a passage which trends approximately due West going downslope. This works OK and the distortion is minimal my elevation comes out looking pretty much like my scrap drawing. [image: TherionElev180.png] But I want to draw my projected elevation sloping down from right to left, as that matches the plan drawing. If I just change the export to [elevation 000] then nothing is output (the map only contains scraps with elevation 180, so the map is not included. If I try to force the map to use -projection [elevation 000] so that it matches the export statement then Therion throws an error saying there is an incompatible projection in my map (because the scrap is elevation 180). Realising that the scrap gets distorted to match the bearing (i.e. I have drawn an extended elevation sketch, but side the scrap is projected at 180), I tried to set the scrap to 'elevation 000'. Afterall, Therion should just distort the drawing to align the stations along on the plane of the projection right? Well sort of. What could be expected to be a simple reversal of the scrap, actually makes quite a mess of it as you can see in the elevation [000] rendering: [image: TherionElev000.png] This looks like a bug in the distortion code. I think the ceiling and floor have been swapped (i.e. Therion has rotated the scrap along a horizontal axis going into the page rather than flipping it left-right. But it has also bent the ceiling and floor lines into some sort of geological folds as well.) Am I missing any tricks here? Do I need to manually try to reproject all my extended elevation sketches onto the projection I want to draw my scraps using, and scan them back in as background sketches? Does anyone know of any tricks to perform the sort of 'horizontal' distortion I need here (i.e. Only moving the pixels of the sketch in the horizontal dimension, not the vertical? I need to learn this inside out so I can write the projected elevations chapter of my tutorial! Footleg
