I have a bunch of polygons (counties) that I need to merge together. They all have various population attributes. I need to be able to selectively merge two counties together and get a single polygon with the combined population totals for the attributes. Is there a way to do this in ArcGIS?
I've tried the Merge tool but while that works for the boundaries, it doesn't work for the adding the two population totals together, you have to pick one or the other. The Dissolve tool seems to operate on all polygons with a single attribute, but there is no unifying attribute that I have that determines which polygons are merged.
Thanks.
Best Answer
As Aaron alluded to in his comment, if any features of a layer are selected prior to using that layer as an input to a geoprocessing tool, the input is restricted to the selection.
In your particular case, you should be able to select two (or more) countries with the Select tool or Select By Attributes/Location dialogs and then run the Dissolve tool, selecting the feature layer (not the path to the actual shapefile/feature class itself) by its name from the input features dropdown menu.
The Dissolve tool has an optional parameter, statistics_fields, where you can SUM the population.