Selon Ophir Yoktan <[email protected]>: Several errors : 1) The NoDataValue and HideNoDataValue elements are only valid under the VRTRasterBand element, not SimpleSource 2) You want to change SimpleSource to ComplexSource, and add a <NODATA>0</NODATA> element in it. (well basically rename your current NoDataValue to NODATA.
> I'm trying to build a mosaic, and I rely on the NoDataValue feature to > treat some parts of the image as transparent. > However, it appears that GDAL doesn't work as expected. > > I also created a very simple test case using a vrt dataset and > gdal_translate - and I get the same results (that is - the 2nd image draws > over the 1st image, ignoring "transparent areas") > > I have to 100X100 image files with a white marking (different in each file) > over black background (black being exactly equal to 0) > I built a simple vrt file: > > <VRTDataset rasterXSize="100" rasterYSize="100"> > <VRTRasterBand dataType="Byte" band="1"> > <ColorInterp>Gray</ColorInterp> > <SimpleSource> > <SourceFilename relativeToVRT="1">a1.tif</SourceFilename> > <SourceBand>1</SourceBand> > <SrcRect xOff="0" yOff="0" xSize="100" ySize="100"/> > <DstRect xOff="0" yOff="0" xSize="100" ySize="100"/> > <HideNoDataValue>1</HideNoDataValue> > <NoDataValue>0</NoDataValue> > </SimpleSource> > <SimpleSource> > <SourceFilename relativeToVRT="1">a2.tif</SourceFilename> > <SourceBand>1</SourceBand> > <SrcRect xOff="0" yOff="0" xSize="100" ySize="100"/> > <DstRect xOff="0" yOff="0" xSize="100" ySize="100"/> > <HideNoDataValue>1</HideNoDataValue> > <NoDataValue>0</NoDataValue> > </SimpleSource> > </VRTRasterBand> > </VRTDataset> > and I run the command: > > gdal_translate mosaic.vrt mosaic.tif > > The result is identical to image `a2.tif`, instead of being a combination > of `a1.tif` and `a2.tif` > > I got the error using gdal 1.8 and 1.9 > > any ideas? > _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
