Conditional statement in gdal_calc with result as float, not boolean

Question

Many examples on gis.se that refer to gdal_calc give a boolean example. example 1 example 2

If I need to calculate a conditional statement on a float:

If Raster_Value >= 1024, then 1024; else Raster_Value.

How do I perform that operation in the gdal raster calculator command line

EDIT I tried radouxju answer and it worked, except for the cell values that didn't. here are 3 kinds of results I got

Here is the tool gui and the parameters I've entered

score 5 · Answer 1 · answered Dec 10 '15 at 11:37

5

you can define the output type using the "type" option

--type=TYPE output datatype, must be one of ['Int32', 'Int16', 'Float64', 'UInt16', 'Byte', 'UInt32', 'Float32']

so it would look like this

gdal_calc.py -A yourInput.tif --outfile=yourOutput.tif --calc="1024*(A>=1024)+A*(A<1024)" --NoDataValue=0 --type='Float32'

answered Dec 10 '15 at 11:37

radouxju

Well, that seemed to work, apart from the fact that certain cells below threshold were changed too. http://i68.tinypic.com/10pxcig.png – HDunn Dec 10 '15 at 11:52
this is strange. Do you also have unexplained results with Float64 ? – radouxju Dec 10 '15 at 13:42
I have a similar question, so, how can I change the pixel value to entire raster? In SAGA GIS it's simple: ifelse (a=0,1,a). How to do this via gdal_calc.py? – Jorge Santos Feb 08 '18 at 14:20
2

I would use "--calc="(a==0)(1)+(A!=0)(A)" – gonzalez.ivan90 Nov 06 '19 at 03:58

1 Answers1