Hi Seth,
Le 31/01/2023 à 14:20, Seth G a écrit :
Hi Even,
Is it correct to say the workflow for OGR layer in MapServer is similar to that
of QGIS?
Not quite, because currently MapServer as you point out use
"materialized geometries" to get the points, the number of rings in a
polygons, etc.
Would using WKB here be any more performant?
In the general case where the geometries in the datasource aren't
encoding using WKB, probably not because you would have to pay for the
WKB serialization & deserialization. It could, perhaps, help, a bit, for
GeoPackage. To get the best performance, you'd need to have 2 code
paths: one for OGR materialized geometry (the current one), and another
one for OGR WKBOnly geometries.
The PostGIS driver already has code to convert from WKB to shape [2] which
could be repurposed.
Yes, if that was done, reusing the WKB -> msShapeObj converter from the
PostGIS connector would be the way to go
Even
Seth
[1]
https://github.com/MapServer/MapServer/blob/f3f05d4cf30af615d5f443a1c47c20b6117e52cb/mapogr.cpp#L250
[2]
https://github.com/MapServer/MapServer/blob/f3f05d4cf30af615d5f443a1c47c20b6117e52cb/mappostgis.cpp#L663
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On Tue, Jan 31, 2023, at 12:27 PM, Even Rouault wrote:
Hi,
Please find for review "RFC 92 text: WKB Only geometries" at
https://github.com/OSGeo/gdal/pull/7149
This RFC provides shortcuts to avoid instantiation of full OGRGeometry
instances
in scenarios where only the WKB representation of geometries is needed. The
hope is to save CPU time.
This is something I wanted to at least experiment. I've mixed feelings
if it's something we actually want to adopt.
Even
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