[postgis-devel] SNapPointToLine : GEOS : where is the code for st_intersects between line and point?

[Nicklas Avén]

I think postgis has native functions for st_intersects when at least one of the geometries is a point. And there is two paths in the code. One that prepares the "not point" geometry if it is to be used multiple times and one that doesn't.

I do not get the idea do far. Is it a tolerance you are implementing? 



Best regards
Nicklad

Skickat från min Samsung Mobil

-------- Originalmeddelande --------
Från: Rémi Cura <remi.cura at gmail.com> 
Datum: 06-11-2013  8:59  (GMT+01:00) 
Till: PostGIS Development Discussion <postgis-devel at lists.osgeo.org> 
Rubrik: [postgis-devel] SNapPointToLine : GEOS : where is the code for st_intersects between line and point? 
 
Hey,
I've been working on a ST_SnapPointToLine for the past week,
by reverse engineering when points are considered to be on line by st_intersect.

The (classic) problem is purely a numerical issue, and I suspect a problem in design of st_intersects.


So far my solution doesn't work for all line, can someone please point me in the right direction in GEOS so I can see if something can be improved regarding precision.

I know where the API is, but I'm looking for the exact part that decide if a point and a line intersects.

Cheers,

Rémi-C
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