lib/vector: improve numerical stability for point-in-polygon calculations#7333
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metzm wants to merge 2 commits intoOSGeo:mainfrom
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lib/vector: improve numerical stability for point-in-polygon calculations#7333metzm wants to merge 2 commits intoOSGeo:mainfrom
metzm wants to merge 2 commits intoOSGeo:mainfrom
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What this PR does:
dig_x_intersect(),Vect__intersect_x_line_with_poly()andVect__intersect_y_line_with_poly()Vect_point_in_poly()whenever possible for consistency and to reduce code maintenance burdenThe motivation for this PR arises from two issues:
Vect_get_point_in_poly_isl()fails for very small or very thin areas. This PR improves this fn by successfully calculating centroid's coordinates for more very small or very thin areas. However, because of fp precision limits, it is technically not possible to calculate centroid's coordinates for too small or too thin areas. In these cases it can not be guaranteed that the centroid is really inside the area.Vect_get_point_in_poly_isl()confirm that the calculated centroid's coordinates are indeed inside the given area,Vect_find_area()might in extreme cases later on assign this centroid to a different area, causing problems with both duplicate centroids and missing centroids.I am not sure if this PR should be regarded as a bug fix or as an enhancement. Suggestions welcome!
Please excuse the many changes in this single PR, but they really belong together.