Fwd: ogr extension

[Nina Hüffmeyer]

Am Mittwoch, 26. Januar 2005 11:51 schrieb Bernhard Herzog:
> Nina Hüffmeyer <nhueffme at intevation.de> writes:
> > Thuban knows three types of geometries: points, lines and polygons. In
> > ogr, more types are known, e.g. geometry type wkbUnknown.
>
> What does wkbUnknown mean?  How is Thuban supposed to treat it?  What
> other types of geometries are there that Thuban may need to support?

Hi Bernhard,

wkbUnknown means that ogr does not know the geometry type of the layer and 
that features of any type of geometry are allowed to be added to the layer. 
There are the following types known in ogr:

wkbNone, wkbUnknown, wkbPoint, wkbLineString, wkbPolygon, wkbMultiPoint, 
wkbMultiLineString, wkbMultiPolygon, wkbGeometryCollection

I don't know how it works exactly, but sometimes Thuban displays the features 
even if they are of geometry type wkbUnknown (e.g. GML files) and sometimes 
it doesn't (PostgreSQL files).
Maybe it would be sufficient if only wkbUnknown was added to Thuban 
(wkbPoint, wkbLineString and wkbPolygon are mapped to already known types) 
and all types which are not point, line or polygon are declared as unknown. 
Then Thuban could just take the list of points given by shape.Points() and 
display them (i guess that's how it works already?).

Nina