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gdalbuildvrt: | |
- use the raster menu, not the processing toolbox as it doesn't allow custom options! | |
- use either -vrtnodata 255 or -addalpha | |
Note that if you use addalpha you can't convert the result to a tiff with jpeg compression | |
gdalwarp: | |
- if using JPEG compression, use -ot=Byte | |
- use tiled output | |
- generate a world file | |
- for better JPEG compression, use -co PHOTOMETRIC=YCBCR | |
How to use this?: | |
--config GDAL_TIFF_INTERNAL_MASK YES | |
Do we have to use it with gdal_translate and this before using gdalwarp?: -b 1 -b 2 -b 3 -mask 4 | |
Converting asc output by 12d, qgis claims it is float64, although all the values are round to the nearest mm, which doesn't match result converted to float geotiff. | |
use these options to set the nodata value: | |
-a_nodata -9999.0 for float64 | |
-a_nodata 0 byte or uint16 or uint32 (0.0 accuracy) | |
float32 doesn't require it!? | |
float32 file size is only a fraction less than float64, and numbers seem to be the same. What?! |
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