Hi! Are the following ways corrects? {x} {x,y,y,z} {x,y,z,w} when lat/lon of y is the same of lat/lon of z {x,y,z,x,w} {x,y,z,w,j} when lat/lon of w is the same of lat/lon of x {x,y,z,w} when segment from z to w intersects the segment from x to y If not, does the api check for them? Should/Must editors/converters avoid them? thanks Niko