[gdal-dev] Failure with osr.CoordinateTransformationOptions()

[Even Rouault]

Stefano,

urn:ogc:def:coordinateOperation:EPSG::1169 is a transformation between 
EPSG:4265 (the geographic CRS of Monte Mario) and EPSG:4326. You cannot 
use it directly when the source CRS is EPSG:3003, which is a projected 
CRS based on EPSG:4265.

You could instead use

options.SetOperation("""+proj=pipeline
   +step +inv +proj=tmerc +lat_0=0 +lon_0=9 +k=0.9996 +x_0=1500000 +y_0=0
         +ellps=intl
   +step +proj=push +v_3
   +step +proj=cart +ellps=intl
   +step +proj=helmert +x=-225 +y=-65 +z=9
   +step +inv +proj=cart +ellps=WGS84
   +step +proj=pop +v_3
   +step +proj=unitconvert +xy_in=rad +xy_out=deg
   +step +proj=axisswap +order=2,1""")

as suggested by the output of projinfo -s EPSG:3003 -t EPSG:4326 
--spatial-test intersects

Even

Le 05/03/2021 à 09:42, Stefano Iacovella a écrit :
> Hi all,
>
> I am trying to use GDAL, via Python bindings, to convert coordinates.
> I would like to select a specific transformation when converting among 
> CRS with different Datums. Reading the documentation my understanding 
> is that I need to create a osr.CoordinateTransformation with options 
> parameter valorized properly.
> I am using binaries from OSGEO4WIN, the release are 3.1.4 for GDAL and 
> 6.3.2 for PROJ
> This is a code snippet I am using to debug:
>
> from osgeo import ogr
> from osgeo import osr
>
> source = osr.SpatialReference()
> source.ImportFromEPSG(3003)
>
> target = osr.SpatialReference()
> target.ImportFromEPSG(4326)
>
> options = osr.CoordinateTransformationOptions()
> options.SetOperation("urn:ogc:def:coordinateOperation:EPSG::1169")
> transform = osr.CoordinateTransformation(source, target, options)
>
> point = ogr.CreateGeometryFromWkt("POINT (1622987 4756952)")
> point.Transform(transform)
>
> print point.ExportToWkt()
>
> I have no errors running it but the coordinates of the point, after 
> the transformation, are infinite. If I create the 
> CoordinateTransformation without options like this:
>
> transform = osr.CoordinateTransformation(source, target)
>
> The point coordinates after transformation are ok but of course the 
> conversion is performed using the Coordinate Operation automatically 
> selected by the system.
> Am I doing something wrong?
>
> Thank you in advance for your help.
>
> All the best,
>
> Stefano
>
>
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> gdal-dev at lists.osgeo.org
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