[postgis-devel] PostGIS Raster problem
belanger_david at live.ca
Thu Oct 20 07:36:38 PDT 2011
I understand what you said but Is it possible
that the GDAL driver uses the ST_MetaData() function of PostGIS ? I’m using GDAL 1.8. I
don’t think that the problem is the version of GDAL because when I'm using
gdal_translate with an old version of PostGIS I'm having a good result but when
I'm using the version r7616 there is a problem. Like I said the x and y of the
upper left corner and the resolution of the data extracted are rounded. It is
exactly the same result of the ST_MetaData() function executed in an SQL API. It
is why I have suspected the problem in the ST_MetaData() function. Do you think
there is an other possibility ? Anyway I will intall the new version of PostGIS
and I will see.
> From: jorge.arevalo at deimos-space.com
> Date: Thu, 20 Oct 2011 10:05:19 +0200
> To: postgis-devel at postgis.refractions.net
> Subject: Re: [postgis-devel] PostGIS Raster problem
> I think it may be a confussion here. If you are using the ST_Metadata
> function, you're NOT using GDAL PostGIS Raster driver. The driver is
> used to read raster data from database without using the SQL API. For
> example, with gdalinfo, or gdal_translate.
> Anyway, which GDAL version are you using?
> On Wed, Oct 19, 2011 at 10:00 PM, David B�langer <belanger_david at live.ca> wrote:
> > Thank you ! I'm using the revision r7616. I will use the current revision.
> > David
> >> Date: Wed, 19 Oct 2011 12:36:46 -0700
> >> From: dustymugs at gmail.com
> >> To: postgis-devel at postgis.refractions.net
> >> Subject: Re: [postgis-devel] PostGIS Raster problem
> >> On 10/19/2011 12:21 PM, David B�langer wrote:
> >> >
> >> > Hi,
> >> > I use the GDAL driver to extract a raster from PostGIS 2.0 but I got bad
> >> > results. The x and y of the upper left corner and the resolution are bad. It
> >> > seems that these properties have been rounded. This problem has appeared
> >> > since the summer version of PostGIS 2.0. I didn't have this problem before.
> >> > I think the problem is in the ST_MetaData() function which is used by the
> >> > GDAL driver. I know that this function was modified this summer. The others
> >> > functions (eg. ST_ScaleX, ST_ScaleY, ST_UpperLeftX...) give good results.
> >> >
> >> > I have compared the result of the summer version of PostGIS with the old
> >> > version.
> >> > The results:
> >> > select ST_MetaData(rast)…:
> >> > Old version of database:
> >> > "(-71.7501041666667,45.5001041666667,1200,1200,0.000208333333333333,
> >> > 0.000208333333333333,0,0,4269,1)"
> >> > Database Since this summer: "(-71.750104,45.500104,1200,1200,0.000208,
> >> > -0.000208,0,0,4269,1)"
> >> > The result of the old version of the database is the truth.
> >> >
> >> > Does anyone know this problem and can you help me?
> >> >
> >> > Thanks !
> >> > David
> >> >
> >> >
> >> What revisions of PostGIS trunk are you using? I rewrote the
> >> ST_Metadata function over the summer and had to tweak it some time
> >> afterwards due to how the values were getting rounded depending on how
> >> the C function returned (Datums vs. CStrings).
> >> After digging through the logs, you'll want to be using r7638
> >> (7/14/2011) or more recent to ensure that your answers are correct.
> >> -bborie
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> Jorge Arévalo
> Internet & Mobility Division, DEIMOS
> jorge.arevalo at deimos-space.com
> postgis-devel mailing list
> postgis-devel at postgis.refractions.net
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