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<body class='hmmessage'><div dir='ltr'>That question is probably for Even, Frank or some the developer of drivers that support mask band.<br><br>I am working on ticket #5621 and trying to adapt it to the RFC 15 but I am not quite sure that I am getting it right.<br><br>In GeoRaster, I can have a bitmap mask band that can be applied to all bands, similar to the concept of GMF_PER_DATASET, I guess. I can also have one bitmap mask band per raster band, but that does not correspond to the others mask flags (GMF_ALL_VALID, GMF_ALHA, GMF_NO_DATA). The data type of my bitmap mask is 1 bit, and there is no implicit connection with Alpha Channel or No Data in a binary bitmap mask, of course.<br><br>So if I have a dataset with just one bitmap mask shared between all the bands, I think I can return the flag GMF_PER_DATASET and promote the values to GDT_BYTE. But if I have bitmap masks for each raster bands, then I don't know what flag to return. I might just lie and say "GMF_PER_DATASET" and when the mask is requested I will take care of returning the correct one.<br><br>Would that works for others drivers participating on gdal_translate/CreateCopy()?<br><br>Of course, if the output driver support just one mask per dataset, there is nothing much we can do.<br><br>By the way, are there any driver that support overviews of mask band?<br><br>Regards,<br><br>Ivan<br> </div></body>
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