Calculating Area

[KimberlyHamm]

Hello,

I'm trying to calculate the area of this circle. I extracted the bands and used the Classification Wizard to categorize everything as either pervious or impervious. I was trying to use the "tabulate area" tool but it says that is for calculating area between two data sets. When I tried using it anyway, it gave me two values but when I add them up, I get 3,134,884. Is this feet? Square feet? And if so the square footage of a circle with a 2km diameter should be 33,815,822ft2. Picture attached if that helps!

Thanks in advance!

[ABishop]

Hello Kimberly,

You can either right-click on the field you want to calculate the area for and choose "calculate geometry" or you can use the geoprocessing tool "add geometry attributes".  I believe the default calculation in Pro is meters?  You can also change the default calculation unit for future use: https://pro.arcgis.com/en/pro-app/2.8/get-started/units-options.htm 

[DavidPike]

If you want the exact raster area (i.e. not a perfect circle, but a circle made from the square raster cells, you just multiply the cell area by the number of cells - Calculating an area in raster (esri.com) )

If you want the area of the circle your raster is approximating - Raster to Polygon (Conversion)—ArcGIS Pro | Documentation then Merge features into one feature—ArcGIS Pro | Documentation then use the methods described by @ABishop

You may also simply use Measure—ArcGIS Pro | Documentation 

[KimberlyHamm]

I want the area of impervious surface (tan) and pervious surfaces (green) calculated separately, not just the area of the circle. 

[DavidPike · Accepted solution]

Multiply the cell count of each by the cell size and you have the area of each. Or if you know the circle area, use simple maths with the ratio between the count of the number of cells of each pervious and impervious.

Otherwise Raster to Polygon (Check on the create multipart option) then the shape_Area field shows the area.