ArcGIS Online for Custom Applications?

[KeithWitt]

My agency is looking to develop an application that uses a list of one or more U.S. county names and a county designation for each one to compute a funding formula. We have ArcGIS Pro desktop and ArcGIS Online and a web map of the counties and their designations, and we'd like to use a map interface to populate the county designation string. Can ArcGIS Online be used to develop a web-based, map interface application where counties are selected on the screen and then input into a formula or would ArcGIS Enterprise be needed? Can the ArcGIS Online map rest endpoint be accessed by other applications? I'm not sure which develop environment or coding language would be used at this point. 

[Katie_Clark]

If I'm understanding correctly, this sounds like something that can probably be done with Arcade, which is supported in ArcGIS Online. 

Where are you wanting to display the results? Do you just need it as another field in the pop-up that displays the calculation result? (if so, Arcade would be perfect). 

You could also look into creating an Experience Builder app which would use a map and an embedded Survey123 form, using ArcGIS Online.

If I'm totally off in my understanding in what you're trying to do, let me know. 🙂

[KeithWitt]

Thank you for your response. We'd like to embed the map interface and application on a public facing website. Ideally, the user would select one or more counties on the map and/or from a drop-down list; those counties would be input into the formula; and the results would be provided to the user. For Arcade, I'm not sure how to capture the list of counties chosen by the user. I'm not too familiar with Survey123 and the levels of geography than can be collected or whether the results can be returned to the user instantly. I'll look into these two options more closely. Thanks again.