GEOSPointOnSurface returns EMPTY for single-point linestring

[strk]

I would expect the single point as an answer instead.

[strk]

Problem is with CentroidLine class intentionally refusing to give an answer for lines with no length.

[strk]

Same with GEOSCentroid, indeed

[strk]

So for GEOSCentroid the answer is correct, in that by definition the CentroidLine class computes the centroid of all segment's midpoint weighted by segment length, so a zero-length segment is not considered.

Now, the algorithm of InteriorPointLine [1] is:

• Find an interior vertex which is closest to the centroid of the linestring.
• If there is no interior vertex, find the endpoint which is closest to the centroid.

[1] ​http://www.vividsolutions.com/jts/javadoc/com/vividsolutions/jts/algorithm/InteriorPointLine.html

But if there's no interior vertex both endpoints are equidistant to the centroid, aren't them ? Martin: am I missing anything ?

[strk]

InteriorPointLine fixed by r3739 in 3.3 branch and r3741 in trunk.

[strk]

NOTE: JTS fixed this in another way, see revision 726 of it. It's to be evaluated if such refactoring belongs to the 3.3 branch or only in 3.4

[strk]

See #613 for the port of JTS issue (it's actually for area)