SkyDemon Forums

NOTAM area polygon self-intersection

http://forums.skydemon.aero/Topic20126.aspx

By mschmoelzer - 9/14/2016 6:49:57 PM

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 Smile

Kind regards
Martin
By Tim Dawson - 9/16/2016 2:27:36 PM

They've made it worse, it would seem. They are now attempting to describe two geographical objects (an area and a route) in one NOTAM which is fraught with the potential for error. Graphical depiction of NOTAM is never perfect because the NOTAM system wasn't designed in that way, but SkyDemon will normally get it right as long as the source data is good. A polygon is generally fine; a line is generally fine; mixing the two is unlikely to work.