I am confused with the results of using a condition in gdal_calc. Initially I thought that gdal_calc was setting pixels to nodata where a condition is not met. In the documentation (http://www.gdal.org/gdal_calc.html) it is said that the following command sets values of zero and below to null.
gdal_calc.py -A input.tif --outfile=result.tif --calc="A*(A>0)" --NoDataValue=0
If I try this command:
gdal_calc.py -A input.tif --outfile=result.tif --calc="A*(A>0)" --NoDataValue=-9999
The pixels where the condition is not met are set to zero.
Should I understand that the term null used in the documentation actually refers to pixels with a value of zero?