Hi. Is it possible to see which of our organization's feature classes are used by which web maps & apps within the organization? We're trying to clean up unused maps & apps and making sure when we delete or revise a FC, we don't break something. Would be nice to have some sort of tree schematic that could be automatically generated or at least a search function that would show all the apps that use it.
Yeeees, I need that badly.
Additionally, it would be great to see in which ArcMap and ArcGIS Pro projects they are used. The amount of times I deleted a view I thought was irrelevant just to have a coworker come to me afterwards and complain that their layer's datasource is broken...
Check out the ArcGIS Python API, specifically the dependent_to / upon properties. According to the API docs, this is only available in Enterprise, not in AGOL, so you may be out of luck.
Alternatively, you can use get_data on the higher-level items like apps and maps to return the JSON definition, and from there pull out the itemIDs of your layers. It would take some doing, but you could probably manager to build a dependency tree from that.
Another thought: using the an item's view property over time, you can identify which maps/apps/layers simply don't get any use, which is usually a good place to start doing cleanup. We run a script that daily pulls view counts for all our content and appends the values to a table with the current date, and that has been very helpful in identifying unused apps, as well as confirming those layers which are in use. Additionally, this method respects usage from other sources, such as desktop software, as a "view" on a feature layer is counted for each query made to the service.