Selon Jonathan Moules <jonathanmou...@warwickshire.gov.uk>: > Hi List, > I have a question about setting a value as "noData" in GeoTIFFs. > > I'm creating a Geotiff with this two stage process (mosaicing a lot of > tiles together): > > gdalbuildvrt -hidenodata -srcnodata 255 -vrtnodata 255 -input_file_list > >> tiff_list.txt 255.vrt > > > > > >> gdal_translate -of GTiff -co TILED=YES -co BIGTIFF=YES -co COMPRESS=JPEG > >> -co JPEG_QUALITY=80 -co BLOCKXSIZE=512 -co BLOCKYSIZE=512 -co > >> PHOTOMETRIC=YCBCR 255.vrt 255mask.tif > > > > > The resultant image is fine, but when I access it, both via ArcGIS and QGIS > it says that there is no noData value set.
Yes, and gdalinfo on 255mask.tif would report the same too. The reason is the "-hidenodata" flag in the gdalbuildvrt. Remove it and it should work as expected. You don't need to rebuild your 255mask.tif. Just try : python gdal_edit.py -a_nodata 255 255mask.tif (cf http://www.gdal.org/gdal_edit.html) > > I've tried reading into it and came across this - > http://www.gdal.org/frmt_gtiff.html - but it requires a deeper level of the > GeoTIFF library than I have to make much sense of it. > > I did see "GDAL_TIFF_INTERNAL_MASK" and tried to set it to true (using -co > and --config), but GDAL just complained about it not being a valid > configuration option. Masks are more unusual and difficult to master. > > Can GeoTiffs have a noData value in them that applications will see and > honour? If so, can I set it in GDAL? > It's not critically important, more nice-to-have and also trying to > understand the format better > > Thanks, > Jonathan > > -- > This transmission is intended for the named addressee(s) only and may > contain sensitive or protectively marked material up to RESTRICTED and > should be handled accordingly. Unless you are the named addressee (or > authorised to receive it for the addressee) you may not copy or use it, or > disclose it to anyone else. If you have received this transmission in error > please notify the sender immediately. All email traffic sent to or from us, > including without limitation all GCSX traffic, may be subject to recording > and/or monitoring in accordance with relevant legislation. > _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
