[mapserver-dev] Implement getNumFeatures for some drivers

Tamas Szekeres szekerest at gmail.com
Sun Apr 22 12:36:44 PDT 2018

Hi Devs,

Currently getNumFeatures is supported by the inline layers only. Would that
be sufficient to implement this for some other drivers, like  MSSQL,
PostGIS and OGR?

The database drivers would probably rely on the count() aggegate in the SQL
query, while we could use  OGR_L_GetFeatureCount for the OGR layers.

I could also imagine a default implementation if we use whichShapes on the
layer extent and iterate the shapes to calculate the count.

It is also a question whether getNumFeatures should consider the layer
filter or not.

Best regards,

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