I've got a web map that has line and polygon hosted feature layers. My customer would like fields in each of those layers for feet and miles in the line layer and acres in the polygon layer to be auto populated as the features get created or updated. I'm stumped as to how to accomplish this. Or, at the very least... fields that he can manually calc when the data comes in from the field.
I see there is shape__length for the lines and shape__area for the polygons but the values for those (presumably in meters and square meters) don't seem accurate or right when I compare them against the web map measure tool. As well, I'm not sure how to get the values for those fields to auto populate these other user defined fields. I can see how to create a custom arcade expression to show various things in the popups but that isn't the same as actually calculating fields and then showing those values.
I see that there is some new functionality in Pro called "attribute rules" that can do this sort of thing... is that extended to AGOL hosted feature layers? And how about Collector? Where does that fit into the mix?
A requirement fro Attribute Rules is having your data in an Enterprise Geodatabase and this functionality is not yet available in ArcGIS Online. If the information is just required for visualization in the attribute table and the pop-up you can use Arcade expressions and define those additional fields as Arcade expressions. They will not alter your data, but the user will be able to see the length and area in the pop-up and attribute table.