I have every municipality in my county separated and exported as different shapefiles. In the attribute table of each of these municipalities I have the Shape_Area which is calculated by the software and I have it separated by landscape type (Agricultural, urban, rural). Now, in some of the municipality shape file attribute tables there is more than one field for a type of landscape so as an example, I have two polygons for agriculture. I want to merge those into one. I use the merge tool and merge them together. I add the total shape area before hand and compare it with what I get afterwards to make sure it's correct. Sometimes this works, but I'm also running into the problem where it subtracts the shape_area amount of just gives me a totally random number? Would anyone be able to help explain why this is happening. I don't change any of the commands, it's just I use the tool for the merge for different parcels, but the type of data is the same. Thank you.