[postgis-users] contains function with complex polygons
Gilbert, Antoine
AGilbert at korem.com
Thu Sep 28 08:51:36 PDT 2006
Yes
I was posting my problem in the JTS forum too because when I realized I
was wrong in my PostGIS application I figured I was too in an old one
using JTS stuff! So I had to verify both.
-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
Markus Schaber
Sent: September 28, 2006 10:55 AM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] contains function with complex polygons
Hi, Antoine,
Gilbert, Antoine wrote:
> I was used to the object model of another software I'm using who is
not
> ogc compliant.
You're not the only one who got caught by this trap.
Differing geometry models are one of the ugliest problems in the GIS
area. Some problems are:
- Polygon vs. MultiPolygon and islands
- (Counter)Clockwiseness of rings
- Repeating the first vertex of a ring as last one
- Are duplicated vertices allowed
- Which kind of "degenerated" geometries are allowed
(1-point lines, 2-point polygons, polygons with area of 0)
etc.
Markus
--
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf. | Software Development GIS
Fight against software patents in Europe! www.ffii.org
www.nosoftwarepatents.org
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