Bug report #18870
SAGA ... Channel Network and Drainage Basins fails due to Threshold being passed as a Real when Integer is required
|Affected QGIS version:||3.1(master)||Regression?:||No|
|Operating System:||Mac OS X 10.12.6||Easy fix?:||Yes|
|Pull Request or Patch supplied:||No||Resolution:|
|Crashes QGIS or corrupts data:||No||Copied to github as #:||26702|
Processing > SAGA > Terrain Analysis - Channels > "Channel Network and Drainage Basins" requires only 2 inputs: Elevation (DEM file) and Threshold (Strahler) value.
In the Processing dialog, Threshold is handled as a Real (i.e., displayed as 5.000) and the function fails; the log messages panel contains "'5.0' is not a correct numeric value for option 'THRESHOLD'." and shows that the function call included "-THRESHOLD 5.0"
In the log's "Usage: saga_cmd ta_channels..." section it describes:
Thus the problem appears to be caused by a Real format value being supplied where an Integer value is required.
This error does occur in QGIS 3.0.0, 3.0.1 and 3.0.2
This error does NOT occur in QGIS 2.18.15
Note: other SAGA routines also expect an integer Strahler Threshold value and might have similar issues.
If someone could tell me how to edit the call I would be happy to test if changing '5.0' to '5' solved the problem.