[MapServer-dev] Using OGR geoparquet data in mapserver - spatial filtering works

[Seth G]

Hi Mike,

I don't think so, but coincidentally I was checking yesterday as it would allow some of the functions such as:

DATA "SELECT ObjectId, ST_Z(geometry) Z FROM mydata"

There is the CONNECTIONOPTIONS block, but this doesn't support a "--dialect" equivalent when testing. It would be nice to do something as follows:

CONNECTIONOPTIONS
    "dialect" "sqlite"
END

Or alternatively adding in:

PROCESSING 'ogr_dialect=sqlite'

The MapServer OGR code would also need to be updated. 

Seth

--
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On Mon, Jul 21, 2025, at 5:52 PM, Michael Smith via MapServer-dev wrote:
> And spatial filtering is working, it was due to BBOX sorting that it was not being very efficient in the spatial filtering.
>  
> Is there a method to use SQLite dialect with MapServer queries with parquet and OGR? Wanted to use SAMPLE but this is only supported via SQLite dialect.
>  
> Mike
>  
>  
> -- 
> Michael Smith
> RSGIS Center – ERDC CRREL NH
> US Army Corps
>  
> *From: *Even Rouault <even.rouault at spatialys.com>
> *Date: *Monday, July 21, 2025 at 10:05 AM
> *To: *Michael Smith <michael.smith.erdc at gmail.com>, MapServer-dev <mapserver-dev at lists.osgeo.org>
> *Subject: *Re: [MapServer-dev] Using OGR geoparquet data in mapserver - no spatial filtering
>  
> Mike,
>>  Anyone know a current way to get mapserver to add spatial filtering on OGR geoparquet layers. Have been unable to get the actual sql query being used with CPL_DEBUG inside mapserver with CONFIG "CPL_DEBUG" "ON" but from the performance, it appears no spatial filtering is being done. I suspect code changes to mapogr would be needed to do this but wondering if anyone else has looked into this.
> 
> I haven't tried but I would assume this should work
> 
> 
>>   Also, I tried using ADBC connection to parquet, and while it worked (technically) it really used an excessive amount of CPU and memory over using the geoparquet driver. 
> Yes this is "expected". I noticed that the Arrow API of duckdb tends to ingest everything in memory before paging results.
> 
> Even
> 
> -- http://www.spatialys.comMy software is free, but my time generally not.
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