Solved! Go to Solution.
Your input features have many overlaps. Here is how you can analyze your input:
1. Use Dissolve tool to make one polygon from the entire input (uncheck "create multipart features"). The area of the output polygon is 30.9 ha.
2. Add a field in the input features table and then use Calculate Geometry to get ha values for all polygons. Check the sum of the all polygon areas - it is 31.03 ha. It is bigger than the area of the dissolved polygon.
3. Run Feature To Polygon tool on the input features. Then add a field and calculate areas. Sort ascendingly the calculated area field. You will see many small values; zoom to these small polygons - they are mostly overlaps or gaps. The larger sum of area comes from these overlaps.
You would need to get the input features cleaned up before doing any spatial processing.
Hope that helps.