I am working on a field survey that looks at sampling algal cover in streams across the Bay of Plenty Region in New Zealand. I am trying to create an error check field that is used to ensure that users enter % cover for algae types that will sum to 100%.
First question is a select multiple where the user selects all algal types that they have at the site. Then the %cover of the relavant algal types is entered by the user. I was to ensure that these % cover of algal types sums to 100% and if it does not - a error message is displayed and the user corrects his cover values.
Here is my construct in excel
the calculation is:
This is what happens below: the algal cover percentages are treated as a text field and the number 50+50 = 5050 instead of 100. I also have a constraint on this value and it must equal 100 (.=100). I have tried integer and decimals fields, and even used the bindesri fields to set them to integer or decimal but with no success.
Has anyone had a similar issue occur to them in a calculation like this. Can I use a sum function instead of additions or is my addition syntax wrong?
Thanks in advance for you help.