I am working with a dataset of the USA Marine Exclusive Economic Zone (EEZ) and a dataset of current Marine Projected Areas (MPAs). Download Data here This is all being done in ArcGIS 10.4. I know that to calculate area I must first transform the layer from GCS to PCS. This does not seem to be a problem.
Next I calculate the area using the add geometry tool on the new PCS-transformed layer. Then I sum the area of the us EEZ I arrive at a value of ~25 Million Square Kilometers! The real size of the USA EEZ should be ~11 Million Square Kilometers.
Furthermore when I sum the area of the US MPA I arrive at a value of ~31 Million Square Kilometers. This is obviously wrong as this should be less than the total EEZ area.
Ultimately I just need to know the percent of area of the EEZ that is covered by an MPA.
Where am I going wrong with the projection or area calculation?