New Feature in Cave Converter: DXF to Survex conversion

[Footleg]

My cave converter tool now reads data from Autocad DXF files and
generates survey legs from the coordinates of the lines and polylines,
output these in Survex format.

See http://www.darkgem.com/wscc/caving-talk/index.php?title=CaveSurveyDataConverter
for details.

This makes it possible to regenerate usable survey data from a survex
.3d file by exporting this as DXF from Aven, and then processing it
using my converter. However I have noticed that the although the
resulting cave model looks the same as the original, the lengths and
total number of stations and legs reported by Survex are different! I
have not done any investigation into it yet, but I think there may be
a bug in the Aven DXF export which is duplicating legs or something.

More usefully this conversion allows old data processed in Autocad to
be regenerated for use in Survex (which was how this feature got
requested in the first place). Hopefully it will prove useful to some
of you for similar situations.

Footleg