[geotk] VerticalCRS transformation

[Aaron Braeckel]

Thanks, Martin.  Your help is very appreciated.

Aaron

On 3/9/2011 4:11 PM, Martin Desruisseaux wrote:
> Le 09/03/11 23:25, Aaron Braeckel a écrit :
>> When I retry this resampling operation with identical VerticalCRSs it
>> results in:
>>
>> Caused by:
>> org.opengis.referencing.operation.NoninvertibleTransformException: Transform is not invertible.
>>    at org.geotoolkit.internal.referencing.MatrixUtilities.invertSquare(MatrixUtilities.java:305)
>> ...
>> Caused by: javax.vecmath.SingularMatrixException: cannot invert matrix
>> ...
>>
>> The result of cvg.getGridGeometry().getGridToCRS().toString() is:
>>
>> PARAM_MT["Affine",
>> PARAMETER["num_row", 5],
>> PARAMETER["num_col", 5],
>> PARAMETER["elt_0_0", 20.318],
>> PARAMETER["elt_0_4", -3332.314824642418],
>> PARAMETER["elt_1_1", -20.318],
>> PARAMETER["elt_1_4", 3983.006785884024],
>> PARAMETER["elt_2_2", 304.8],
>> PARAMETER["elt_2_4", 3048.0],
>> PARAMETER["elt_3_3", �],
>> PARAMETER["elt_3_4", 1.0]]
>
> I suspect that the matrix is considered non-invertible because of the 
> Double.NaN value in the 4th matrix row (the � symbol in above WKT). 
> Geotk puts a NaN as the scale factor for dimensions for which 
> CoordinateSystem1D.isRegular() 
> <http://www.unidata.ucar.edu/software/netcdf-java/v4.2/javadoc/ucar/nc2/dataset/CoordinateAxis1D.html#isRegular%28%29> 
> (from the UCAR API) returned false. Assuming we are not facing a Geotk 
> bug, I would guess that the 4th dimension in your dataset is the time 
> dimension and contains non-evenly spaced data.
>
> Tomorrow, I will add some code logic for making matrix inversions more 
> tolerant to NaN values. It will hopefully be done by the end of the 
> day (I know precisely how to do that).
>
>     Regards,
>
>         Martin
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/geotoolkit/attachments/20110309/1a2c6064/attachment.html