[postgis-devel] Testing ST_LineMerge issue

[Mark Cave-Ayland]

Kevin Neufeld wrote:

> To answer your question Mark, the OGC specs say that a LINESTRING is 
> simple if it does not pass through the same point twice.  To me, this 
> means self-intersections and perhaps coincident vertices.  At the 
> moment, PostGIS returns true for this when by rights it should be false:
> SELECT issimple('LINESTRING(0 0, 1 1, 1 1, 2 2)');
>  issimple
> ----------
>  t
> (1 row)
> 
> Something to look into?  Are coincident vertices considered to be a 
> self-intersection?

Hmmm I'm really not sure, although my intuition would say it is a 
self-intersection.


ATB,

Mark.

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Mark Cave-Ayland
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