My CRS is WGS 84. I intersected two files containing polygons. Each file has an attribute table stating the area of each of the polygons (in m2). After intersecting them I navigate to: Vector >> Geometry Tools >> Add Geometry Attributes. The area of the new polygons are calculated but they are orders of magnitude different to the original polygons. For instance, when comparing a new (smaller) polygon to the original (larger) polygon (which are only slightly different), the new area is calculated as 28.08 and the original is 243,943,129,649 m2
There is no way that these can be the same units. How can i find out the units of the new polygons?
Best Answer
Geometry calculations and operations (area, length, buffer) are done based on the CRS of the layer. So, if your layer is in WGS84, your area is measured in square-degree. Not really useful.
Either save your layer using any projected CRS, or you run something like
area(transform($geometry,'current EPSG','projected EPSG')).