there is an easy way to check whether a point is IN a polygon

you create an aribtary point OUT of the polygon

then you check if the line from the being-checked point and the arbitary point touches all other lines
you count how many lines it touches
if the number is even you know that the point was IN the polygon

check it out on a paper

Arkon
[QSoft Systems]

Really? I didn''t know that.