Make an optional input parameter in QGIS Processing Algorithm Script

Sunday, 26 August 2018

My version of QGIS is 2.8.3

I have a tool which takes parameters like this:

##Input_Vector_Layer=vector
##Input_Raster_Layer=raster
##Distance=number 1.0

##Height=field Input_Vector_Layer

# Do Something...

Is it possible to make the fourth parameter optional?

Answer

If it's not a problem for you, my idea is to add a Boolean:

##Input_Vector_Layer=vector
##Input_Raster_Layer=raster
##Distance=number 1.0

##Height=field Input_Vector_Layer
##Use_Optional_Field=Boolean True

and the directly check for its value:

check = Use_Optional_Field
if check:
    # Do something...
else:
    # Do something else

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