I have an image of a scanned cave plan that I have attached to a scrap as a ‘background sketch’ and am exporting to a pdf. I have a point for the entrance and a have used a made up survey line to produce a rudimentary therion model on which to hang the scanned image and produce a loch model to view with a 3d surface.

All list, 2d map and 3d model outputs that I have tried (I have not tested all possible variants) are created perfectly, except that for 2d pdf map outputs when the sketch is activated with ‘sketches on’, the extent of the area mapped extends about 1km too far left and too far upwards. The extents should be 1km x 0.4km, so something is more than doubling the extent. The image is cropped tightly to the cave and there are no spurious survey stations causing this. I am using ‘rotate 70’. Have not had this effect before, and the only thing unusual from my point of view is that the image has a transparent background so that the aerial photograph can be seen overlaid on the cave. I can not see anything wrong with the th2 file (as follows)

##XTHERION## xth_me_area_adjust -28.0 -294.0 6134.0 2316.0

##XTHERION## xth_me_area_zoom_to 25

##XTHERION## xth_me_image_insert {100.0 1 1.0} {2188.0 {}} sketches/SUMMITTO_Clear2.png 0 {}

point 712.0 28.0 station -name 19@S

point 4604.0 1328.0 station -name 4@S

point 5440.0 1884.0 station -name 1@S

endscrap

Any ideas as to why a background sketch should make therion think the extent of the cave is so much bigger?

-A problem with my image file?

-A problem with one of my therion data files (I think I have ruled those out, but I may have missed something)?

-A bug?

Bruce