[postgis-users] Splitting a Polygon with a Linestring
chris.hermansen at timberline.ca
Wed May 21 14:58:48 PDT 2008
"Some day I hope to get this into JTS/GEOS"...
Go, Martin, go!
Martin Davis wrote:
> That should work. You may also have the problem of determining which
> of the resultant polygons fell on each side of the drawn line. The
> usual way to do this would be to run some point-in-polygon queries.
> It's amazing how much this use case comes in many different venues
> (PostGIS, GUI tools, etc). Some day I hope to get this into JTS/GEOS
> as a provided operation, at which point this will be much easier to
> James Beaudoin wrote:
>> I think the steps below will work but I have one question. I am
>> creating an application that allows a user to split a polygon by
>> drawing a linestring across the polygon they wish to change. The
>> crossing linestring has parts that are outside the polygon and I want
>> to remove that before I geomunion. What's the easiest way to do that?
>> - extract the lines that make up the polygon
>> - add to this your crossing linestring
>> - geomunion the lines together.
>> - polygonize the union-ed set
>> postgis-users mailing list
>> postgis-users at postgis.refractions.net
Chris Hermansen mailto:chris.hermansen at timberline.ca
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