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Re: [udig-devel] Spatial Queries using CQL in uDig
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That is kind of what I was thinking Andrea; right now there is some code that already coverts from the screen bounds into the data bounds; perhaps we could teach this code to be aware of the dwithin units and also convert the distance into the data space?
I cannot remember if this code is in the renderer or part of the datastore's themselves?
Jody
On 12/04/2010, at 9:13 PM, Andrea Aime wrote:
> Jody Garnett ha scritto:
>> I had not thought of that; I always figured that the datastore should
>> handle this part (especially if the actual units are provided). If
>> people are keen we could review the postgis code and make a utility
>> method for the various datastore implementations to call?
>
> Very few data sources actually have the machinery to deal with
> dwithin on geographic data.
> PostGIS does only starting with version 1.5, Oracle does,
> I guess probably DB2 does too, maybe SDE too.
> That said, I have no idea if the SQL encoders actually pass
> down the unit.
>
> To support shapefiles we'd have to add code to make the in
> memory dwithin take care of the math necessary to compute
> point to line distances on an ellipsoid (the code I was
> referring to before)
>
> Cheers
> Andrea
>
>
> --
> Andrea Aime
> OpenGeo - http://opengeo.org
> Expert service straight from the developers.
> _______________________________________________
> User-friendly Desktop Internet GIS (uDig)
> http://udig.refractions.net
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