[postgis-users] contains function with complex polygons

[Markus Schaber]

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

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