Opened 9 years ago
Closed 5 years ago
#5767 closed defect (wontfix)
gdal_calc: input data type used for output values
| Reported by: | cdestigter | Owned by: | Robert Coup |
|---|---|---|---|
| Priority: | normal | Milestone: | closed_because_of_github_migration |
| Component: | PythonBindings | Version: | svn-trunk |
| Severity: | normal | Keywords: | |
| Cc: | antonio |
Description (last modified by )
We're using gdal_calc.py like this to replace alpha with nodata (-1) in RGBA and grey+alpha images:
gdal_calc.py -A in.tif -B in.tif --A_band 2 --B_band 1 --outfile out.tif --calc="where(A < 128, -1, B)" --type=Int16 --NoDataValue=-1
The --calc formula should replace all transparent-ish pixels with -1, which is a valid value for the output image because it's an Int16 image.
However it seems gdal_calc is doing the type conversion implicitly, after the output values are calculated. So the -1 gets wrapped into a byte, and the values all get set to 255 instead of -1.
This patch fixes the problem by explicitly converting the array's data type, earlier in the process: https://github.com/koordinates/gdal/commit/efea5dafaf536213faadbbc3f671591aa6aa8c30
Change History (3)
comment:1 by , 9 years ago
| Description: | modified (diff) |
|---|---|
| Owner: | changed from to |
comment:2 by , 9 years ago
| Cc: | added |
|---|
comment:3 by , 5 years ago
| Milestone: | → closed_because_of_github_migration |
|---|---|
| Resolution: | → wontfix |
| Status: | new → closed |
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