Frank Warmerdam wrote:
Ozy Sjahputera wrote:
I am trying to create image overviews for a GTiff file using
GDALDataset::BuildOverviews. I keep getting various errors such as:
ERROR 1: TIFFSetField:VISUAL.tif: Cannot modify tag "Compression"
while writing
...
writing
ERROR 1: TIFFSetField:VISUAL.tif: Cannot modify tag "TileLength" while
writing
ERROR 1: TIFFBuildOverviews:Can not write tiles to a stripped image
Here is my code:
int OverviewList[5] = { 2, 4, 8, 16, 32 };
CPLErr overview_err = outDS->BuildOverviews( "AVERAGE_MAGPHASE", 5,
OverviewList, 0, NULL, NULL, NULL );
I have used BuildOverviews before on HFA images and they are fine. Any
idea?
Ozy,
I'm surprised. I wonder if you might have opened your file in read-only
mode? Can you reproduce the problem with the gdaladdo commandline program?
Best regards,
Frank,
I'm encountering this issue pretty frequently. It happens when I create
a tiled, compressed tiff (I'm using python but apparently that doesn't
make a difference), write tile data into it, and then call the
buildOverviews method. I thought I'd reported this issue (at least to
this list), but it might have slipped my mind. Because I've found and by
default implemented a fairly simple workaround, I totally forgot about
it till now. The workaround is simple: first close and reopen the
dataset, then buildOverviews. Haven't tried if flushing instead of
reopening is enough.
Should I file a ticket on this?
Vincent.
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