To reproduce zoom in far, into an area with points, and select an area within that does not contain any. LAG will segfault.

It would be useful sometimes to see the point selected highlighted in some way.

The script used to generate DEMs for UK flightlines (nextmapdem.sh) currently only takes into account the start and end position of the aircraft on each line (because it reads these from the header files). This means that on long lines where there is an entire BNG tile between the start and the end it may not include DEM data for the whole flightline.

Possible solutions:

1. (Preferred): Read SBET file in (using sbet_handler.py, unless you've got a pressing reason to do it another way), track position of aircraft and do maths on swath width to work out which BNG tile the aircraft is over (ensuring it's in the UK as well).
2. (Possibly easier): Adapt existing nextmapdem.sh script to be more intelligent about what tiles might be in the middle. May be easier but might be complicated by corner case and/or case where rolls over tile edge (9->0).