Feature request #7581
raster calculator really needs support for conditional statements (to allow reclassify rasters)
| Status: | Open | ||
|---|---|---|---|
| Priority: | High | ||
| Assignee: | - | ||
| Category: | Rasters | ||
| Pull Request or Patch supplied: | No | Resolution: | |
| Easy fix?: | No | Copied to github as #: | 16517 |
Description
One of the most common tasks a user can do in a raster workflow is to reclassify raster maps.
At this stage the raster calculator does not support conditional statements, so it is not possible to say (for example):
(ASTGTM2_N37W026_dem@1<=30)=1 OR (ASTGTM2_N37W026_dem@1>30)=2 OR (ASTGTM2_N37W026_dem@1>200)=5
the workaround is awful
(ASTGTM2_N37W026_dem@1<=30)*1 + (ASTGTM2_N37W026_dem@1>30)*2 + (ASTGTM2_N37W026_dem@1>200)*3
as the raster calc just return 1 or 0, so the user must multiply for the needed value doing also a few sums along the way (because it is not possible to use conditions).
Related issues
History
#1
Updated by Alexander Bruy about 11 years ago
Probably related to #4476
#2
Updated by Michael Douchin over 10 years ago
I agree. For example, we could use full expression syntax, such as
CASE WHEN raster1@1 > raster2@1 THEN raster1@1 ... ELSE raster2@1 END
It is related to #4815 too
#3
Updated by Giovanni Manghi over 10 years ago
- Target version set to Future Release - High Priority
#4
Updated by Luiz Andrade over 7 years ago
Agreed, this would be great!
#5
Updated by Giovanni Manghi over 7 years ago
- Easy fix? set to No