msOffsetPolyline does not handle lines with 1 point #4383

petlof opened this Issue Jul 6, 2012 · 2 comments

2 participants


msOffsetPolyline crashes if a line with only 1 point is available.

Currently this can occur since when offsetting lines coordinates are first transformed to image-coordinates, rounded to integers and then duplicates are removed.
Short lines can therefore end of with only 1 point.

Don't know if msOffsetPolyline should handle this, or if the reduction algorithm should make sure that a line at least contains two points.


See also: #4382

@tbonfort tbonfort was assigned Jul 16, 2012
MapServer member

msOffsetPolyline definitely can't handle this itself as there is no way to calculate an offset direction. The segfault should be corrected in this case. also see #4143 for an undocumented (as of yet) workaround, whereyou can change the simplification method use for that specific layer so the lines are not degenerated into a single point.

@tbonfort tbonfort closed this in bca7fd1 Jul 16, 2012
@mkofahl mkofahl pushed a commit to faegi/mapserver that referenced this issue Apr 9, 2013
@tbonfort tbonfort don't crash on ofsetting degenerate lines (#4383)
closes #4383
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