D'accord.
Even Rouault wrote:
Le Friday 27 March 2009 20:05:11 Lucena, Ivan, vous avez écrit :
Even,
I see. You are right. With the absence of ComputeRasterStatistics() I got
confused and I made the wrong
assumption. BTW, why there is no wrapper for ComputeRasterStatistics()? That
would work then:
bd1.SetStatistics(bd2.ComputeRasterStatistics())
Because you don't use the latest and greatest GDAL ;-)
Extract from swig/include/Band.i from SVN head:
/* Interface method added for GDAL 1.7.0 */
%apply (double *OUTPUT){double *min, double *max, double *mean, double
*stddev};
%apply (IF_ERROR_RETURN_NONE) { (CPLErr) };
CPLErr ComputeStatistics( bool approx_ok, double *min = NULL, double *max =
NULL, double *mean = NULL, double *stddev = NULL,
GDALProgressFunc callback = NULL, void* callback_data=NULL){
return GDALComputeRasterStatistics( self, approx_ok, min, max, mean,
stddev, callback, callback_data );
}
%clear (CPLErr);
Not a big deal. The work around is easy.
Thank you very much,
Ivan
-------Original Message-------
From: Even Rouault <even.roua...@mines-paris.org>
Subject: Re: [gdal-dev] python-gdal ComputStatistics return just two
values Sent: Mar 27 '09 18:45
Hi Ivan,
I don't think there's a bug.
The C API for ComputeBandStats is :
CPLErr CPL_DLL CPL_STDCALL
GDALComputeBandStats( GDALRasterBandH hBand, int nSampleStep,
double *pdfMean, double *pdfStdDev,
GDALProgressFunc pfnProgress,
void *pProgressData );
So, the python API is consistant with it.
So it is expected that "bd1.SetStatistics(bd2.ComputeBandStats())" will
fail as it is provided with 2 values instead of the expected 4.
Best regards,
Even
Le Friday 27 March 2009 19:02:14 Lucena, Ivan, vous avez écrit :
> Hi there,
>
> I believe that ComputeBandStats() should return 4 values min, max,
> mean and stddev) [1] but the Python API is returning just mean and
> stddev.
>
> python:
> >>> bd.ComputeBandStats()
>
> (9.0071713001936118, 11.350094331448236)
>
> >>> bd.ComputeRasterMinMax()
>
> (-1.7899999618530273, 31.149999618530273)
>
> gdalinfo:
>
> Band 1 Block=360x1 Type=Float32, ColorInterp=Gray
> Min=-1.790 Max=31.150
> Minimum=-1.790, Maximum=31.150, Mean=9.007, StdDev=11.350
> Unit Type: unspecified
> Metadata:
> STATISTICS_MINIMUM=-1.789999961853
> STATISTICS_MAXIMUM=31.14999961853
> STATISTICS_MEAN=9.0071713001936
> STATISTICS_STDDEV=11.350094331448
>
> Is that a bug?
>
> See what happens in that case:
> >>> bd1.SetStatistics(bd2.ComputeBandStats())
>
> Traceback (most recent call last):
> File "<interactive input>", line 1, in <module>
> File "E:\Python25\Lib\site-packages\osgeo\gdal.py", line 729, in
> SetStatistics return _gdal.Band_SetStatistics(*args)
> TypeError: Band_SetStatistics() takes exactly 5 arguments (2 given)
>
> My best regards,
>
> Ivan
>
> [1] http://www.gdal.org/gdal_8h.html#a93b6b6ea6e71017ce25524e1a9ef1e3
>
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