Hi, 

I noticed that sometimes the area highlighting feature of SkyDemon generates self-intersecting polygons. For example, this NOTAM:

D) DAILY 1600 - 2130
E) NIGHT VFR TRAINING FLIGHTS (NVG OPS)
BURGENLAND AREA OBERWART:
473120N 0161150E
472750N 0163820E
470250N 0160720E
470050N 0162850E
START HELIPORT OEAMTC OBERWART LODO
PARTICIPATING HELICOPTER: OEXEK OR OEXEQ (EC 135) MONITORING
134,675MHZ
F) GND G)2500FT AGL

is displayed as a self-intersecting polygon - see the images in this gallery: http://imgur.com/a/Sx3i8

I assume this happens due to the order of the vertices (coordinates) in the NOTAM - I think this feature would look much nicer if there was some algorithm involved which can detect this condition and re-order the vertices 

Kind regards
Martin

Thanks, that makes sense to me. I didn't know there was a guideline for drawing polygons in NOTAMs (Google found this document, see page 2-55) which even says that a polygon shall be closed by specifying the first coordinate as the last entry in the list, so even if the hourglass shape was intended, they did not fully follow these guidelines...