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).

Build number: 2010.01.18.1 system : pmpc974

to reproduce, start lag up with no arguments, go to file, open, select any las file and select the fence option, click add. the command line will print some errors, then click refresh with any file and fence on or off. I expected to be warned i hadn't defined a fence on trying to load the first file and expected it to correctly load a file subsequently with the fence option off, instead it crashes and generates a bug report

build number : 2010.01.18.1 system : pmpc974

to reproduce, open a selection of files (tested with 2, 3, 4, and 5 files) with fence unticked and any number of skipped points. Then click fence and select and area of the lines, click file, open and then check the fence box and click refresh. the expected result is to see the fenced area of the lines appear identically to when they were displayed as part of the overall lines. However the fenced lines display with different flight line colours.