This question follows Seeking 1990 US Commuting Zone shapefiles?
I am attempting to map US commuting zones as defined in 1990. I have successfully mapped counties from a county shapefile obtained here. After completing the following advice, I get the error message below:
In the xls, there is a column called CZ90 which I assume is the 1990 commuting zone code. Once you've joined XLS to FIPS shapefile, use the dissolve tool with the CZ90 field as the dissolve field to output a shapefile/feature class with one polygon per commuting zone.
I used the dissolve tool and checked CZ90 as my only field; however, I get the following error message. It appears that I correctly joined the CZ90 excel file with the FIPS shapefile.
How can I successfully dissolve the counties into commuting zones?