I have a county level database of population statistics and am creating a model that will add a new field to the database, pop_density (population density). After adding the new field, I want the model to calculate the population density by dividing population by area. Both population and area already exist in my database.
I insert the Calculate Field tool and specify as the input for Calculate Field the output file from the Add Field tool. When I go to input the expression for pop_density in Calculate Field, it only shows me the Pop-Density field I just added, and it does not show me any of the pre-existing fields in my database. How do I use the Calculate Field tool when one of the variables in the calculation formula does not exist until the model has been run?
