I have a points shapefile which has two fields that I want to use to determine the size of each point. One field, "StepYear", refers to the year of step change in a particular time series, and it contains both numbers (e.g. 1996), and non-numericals (such as NA or – ). The non-numericals indicate a number of different cases in which the test did not proceed.
If the test did not proceed, then I want the size of the point to be equal to 2. Otherwise, I want the size to be determined by the statistical significance of the test. I want code similar to the following:
CASE
WHEN NOT ISNUMBER("StepYear") THEN 1
WHEN "StepSig" <= 0.01 THEN 8
WHEN "StepSig" <= 0.05 THEN 6
WHEN "StepSig" <= 0.1 THEN 4
ELSE 2
END
However, I haven't been able to find any function that performs the "ISNUMBER" check. Is there a function in the QGIS field calculator which outputs TRUE/FALSE for a numerical type check?
Best Answer
Following the comment by @ahmadhanb, this is a workaround I would suggest:
Above
to_int()
part will extract numbers from "StepYear" or return NULL. Please make sure the new field created by this expression isinteger
type.