I have two similar geodatabase feature class (polygons) layers provided by two different sources in the WGS 1984 system and they have the same angular area (decimal degree). While projecting in World-cylindrical equal area (the projection system I need) they are different by more than 5 sq km.
What is the reason?
I need both of them to have the same area in sq km or ha or miles etc.
I am working in ArcGIS 10.3.1