Getting my feet wet(ter) with Survey 123 and not quite sure how to implement input validation for a specific section of my form.
The form is for field data collection along sampling transects. As you see below, the user specifies the overall length of the transect, and the length of the transect that would be within wetland. Once the wetland length of the transect is known, I use a calculation to subtract the specified wetland length value from the total length value to derive the wetland buffer length.
This all works but if I enter a wetland length greater than the total length of the transect, it will calculate a negative number as shown in my screenshot. I've added a constraint on the wetland length input but my understanding is that constraints are actually triggered when attempting to submit the survey rather than as real time data validation.
Any suggestions? FWIW, here's my XLSForm:
