topic Changing units in attributes for shape area in ArcGIS Online Questions

Changing units in attributes for shape area

JennaChisholm — Mon, 18 Dec 2017 10:09:29 GMT

I am looking to change the units in the attribute table from sq m's to hectares?

I know the shape area is auto calculated for when drawing the boundaries but it automatically measures in sq m's, any help/guidance on how to change would be great

Thanks

Re: Changing units in attributes for shape area

XanderBakker — Mon, 18 Dec 2017 11:42:46 GMT

I think the easiest way would be to create an Expression with ArcGIS Arcade | ArcGIS for Developers . Just configure the pop-up and add an expression and as expression enter this:

$feature.Shape__Area / 10000.0‍

It will show up in the pop-up window

... and attribute table.

Re: Changing units in attributes for shape area

JCooley_ClackamasSWCD — Wed, 06 Oct 2021 16:24:12 GMT

This is a bad approach if you want to show the actual area of the polygon. If you use Shape__Area for the pop-up calculation you will end up with the planar area of the polygon. Hosted feature layers always use Web Mercator. This coordinate system does not preserve shapes. The further you get from the equator the more distorted it gets. This is usually not even close to the area in the real world. For example, when you get to 45 degrees latitude the planar area of a polygon is about a 2 times the geodesic area. You can use arcade to calculate the geodesic area for your polygons after adding an additional field to hold the values. Divide this number by 1,000 to get hectares.