I've been using dissolve to successfully merge polygons (which may or may not overlap) representing mining tenements so that I can calculate their total coverage area (using the geodesic area calculator). However, in one case the output of the dissolve has an 11% greater area than the total area of the input polygons.Have attached a picture of the output.
The input data is from multiple shapefiles. I've selected and merged these into one feature class. I've repaired the geometry of the feature class before running the dissolve.
The dissolve output feature is complex with multiple slivers. I thought that these slivers may be the problem. But eliminating some of them made very little difference to the geodesic area calculation. I'm baffled!
Does anyone gave any suggestions?