OGR virtual spatial data
Kralidis,Tom [Burlington]
Tom.Kralidis at EC.GC.CA
Thu Sep 8 04:40:43 PDT 2005
Thanks Bart. I'll upgrade to the GDAL 1.3.0 and test again.
As far as the ovf file syntax:
<OGRVRTDataSource>
<OGRVRTLayer name="somelayer">
<SrcDataSource>ODBC:u/p at foo</SrcDataSource>
<SrcLayer>somelayer</SrcLayer>
<GeometryType>wkbPoint</GeometryType>
<LayerSRS>WGS84</LayerSRS>
<GeometryField encoding="PointFromColumns" x="x" y="y"/>
</OGRVRTLayer>
</OGRVRTDataSource>
So I'm assuming newer versions of GDAL will pass the spatial filter
(from WMS, mapserv CGI, shp2img -e etc.) and apply them to the WHERE
clause to emulate a bbox filter?
..Tom
> -----Original Message-----
> From: UMN MapServer Users List
> [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On Behalf Of Bart van
> den Eijnden
> Sent: Thursday, 08 September, 2005 02:03
> To: MAPSERVER-USERS at LISTS.UMN.EDU
> Subject: Re: [UMN_MAPSERVER-USERS] OGR virtual spatial data
>
>
> Tom,
>
> this depends on your GDAL version. A few months ago Frank did
> an enhancement for us which added the X and Y columns to the
> WHERE clause. Before that, yes, all records were fetched.
>
> Also, depending on your ovf file syntax, the driver might get
> a list of all the tables in the database. I don't know if
> your schema has many tables in there?
>
> Best regards,
> Bart
>
> Bart van den Eijnden
> Syncera IT Solutions
> Postbus 270
> 2600 AG DELFT
>
> tel.nr.: 015-7512436
> email: BEN at Syncera-ITSolutions.nl
>
> >>> "Kralidis,Tom [Burlington]" <Tom.Kralidis at EC.GC.CA>
> 09/08/05 1:13 am
> >>> >>>
> Hi,
>
> I have a MySQL table which I'm connecting to via OGR's
> virtual spatial data option and unixODBC. The table has ~ 2
> million records with x and y columns. I have setup an .ovf
> and mapfile accordingly.
>
> When I run shp2img, CPU usage spikes up to 100% and then a
> core dump results. I am running shp2img with an extent which
> will result in far less records.
>
> Any idea what's going on here? Are all the records being
> fetched BEFORE the spatial filtering by shp2img?
>
> Thanks
>
> ..Tom
>
> =========================
> Tom Kralidis
> Senior Systems Scientist
> Environment Canada
> Tel: +01-905-336-4409
> http://www.ec.gc.ca/
>
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