[postgis] Error in creating WKBPolygon by Postgis

Dave Blasby dblasby at refractions.net
Tue Sep 4 14:37:48 PDT 2001


Hisaji ONO wrote:
> 
>  Thank you very much, Dave.
> 
> > I've added full[er] support for the WKB type.
> >
> 
>  "full[er] support for the WKB type" includes creating spatial indexes for
> WKB-type items or not?

No, there are no operations you can perform on the WKB types.

If you want spatial indexing you have a few choices.

One of them is to just have a GEOMETRY column.  You can use the spatial
index on this column, and retrieve results using the asbinary() command.

The other is to create two columns, one with GEOMETRY and the other as
the WKB representation of the geometry.  You can use the spatial index
on the GEOMETRY column, but get information out of the WKB column.

For example,
The first method, queries would look like;
SELECT asbinary(<geometry column>) FROM <table> WHERE <geometry column>
&& <bounding box>

And the second method would look like;
SELECT <wkb column> FROM <table> WHERE <geometry column> && <bounding
box>

The major difference being that the 1st method requires translating the
internal GEOMETRY format to the WKB format for every query.

dave

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