With reference to my previous messages concerning GRASS reporting
'degenerate lines' when I run v.support on my imported DXF, I believe
I've found the cause. The problem line was an arc whose start angle was
279 and finish angle was 5 - this was converted to a line consisting of
ONE point - hardly the best line ever 
I manually amended the finish angle to 365, i.e. 5 + 360, and then
reimported - worked fine and v.support didn't report any problems.
I've checked the add_arc.c source code and believe that adding a
statement in the second case ensuring that the finish angle is always
greater than the start - by adding 360 degrees.
case 50:
start_angle = atof(dxf_line);
sflag = 1;
break;
case 51:
finish_angle = atof(dxf_line);
fflag = 1;
break;
Any thoughts ??
Steve Culshaw
NRA North West
e-mail : nra@cix.compulink.co.uk (use this for general usage)
or sculshaw@cix.compulink.co.uk (Private - only checked at best
biweekly)