[postgis-devel] Question about GDALDriverManager + gdal2wktraster

[Jorge Arévalo]

Hello,

I have two versions of GDAL in my machine:

- GDAL 1.7.0 from SVN
- GDAL 1.7.0 with the WKT Raster driver I'm developing

Today, I've updated the wktraster code from svn. I have the revision 4256.
The last one. With this revision, there is a new version of gdal2wktraster
script.

I loaded this image
ftp://ftp.remotesensing.org/geotiff/samples/gdal_eg/cea.tif with and old
version of gdal2wktraster, that allowed GDAL to select the block size for
the tiles. Then, I could load the image with default tiles of 514x15, 35
tiles.

But with the new version of the script, I have to specify the block size by
hand. For example, 514x15 (or 100x100). When I try this:

gdal2wktraster.py -r cea.tif -t table_name -s 4267 -b 1 -k 514x15 -I -M -o
output.sql -v

I get this error:

ERROR 7: Assertion `FALSE' failed
in file `gdaldrivermanager.cpp', line 309

Reviewing the code, I saw that the last script's instruction called is:

pixels = band.ReadAsArray(xoff, yoff, valid_read_block_size[0],
valid_read_block_size[1],
                                  target_block_size[0],
target_block_size[1])

That, somehow, should call the method "GDALDriverManager::RegisterDriver(
GDALDriver * poDriver )" from gdalmanager.cpp. The code of the method is
this:

int GDALDriverManager::RegisterDriver( GDALDriver * poDriver )
{
    CPLMutexHolderD( &hDMMutex );

/* -------------------------------------------------------------------- */
/*      If it is already registered, just return the existing           */
/*      index.                                                          */
/* -------------------------------------------------------------------- */
    if( GetDriverByName( poDriver->GetDescription() ) != NULL )
    {
        int             i;

        for( i = 0; i < nDrivers; i++ )
        {
            if( papoDrivers[i] == poDriver )
            {
                return i;
            }
        }

        CPLAssert( FALSE ); // -------> THE LINE THAT CAUSES THE CRASH
*******************************************
    }

/* -------------------------------------------------------------------- */
/*      Otherwise grow the list to hold the new entry.                  */
/* -------------------------------------------------------------------- */
    papoDrivers = (GDALDriver **)
        VSIRealloc(papoDrivers, sizeof(GDALDriver *) * (nDrivers+1));

    papoDrivers[nDrivers] = poDriver;
    nDrivers++;

    if( poDriver->pfnCreate != NULL )
        poDriver->SetMetadataItem( GDAL_DCAP_CREATE, "YES" );

    if( poDriver->pfnCreateCopy != NULL )
        poDriver->SetMetadataItem( GDAL_DCAP_CREATECOPY, "YES" );

    int iResult = nDrivers - 1;

    return iResult;
}

So, basically, with the base 1.7.0 version of GDAL, I can load the TIFF
file. With my version, crash in the previous method. Clearly, it's my
driver's problem, but I don't know why. I have a test code to create a
dataset using my driver and works... Why could the application crash when
trying to list the registered drivers while loading a TIFF file? I have the
TIFF driver loaded in my GDAL version.

Thanks in advance,

Best regards
Jorge

Paula Poundstone<http://www.brainyquote.com/quotes/authors/p/paula_poundstone.html>
- "I don't have a bank account because I don't know my mother's maiden
name."
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