I am trying to get the area coverage of a layer in my map, and the two methods I've used to do so are producing different results.
I used dissolve to create one feature in the layer and get the SHAPE_Area off the attribute table, and then I unioned the layer and summed the areas from that result. The dissolve is giving me 654901660.917106 m^2, and the summed union is giving me 1316663489.162411 m^2. Everything is using the same projected coordinate system. Anybody know what is happening?? This is driving me crazy...