Get Congressional District output with location (lat, lon) input using REST call.

Question

I'm developing an application which has a java backend servicing a REST API and a front end using Angular 8. I need to create a function that accepts lat, lon and returns the congressional district the point is located in.

Can anyone suggest how I might do that?

Thank you

jcarlson · Accepted Answer

Using, for example, the Census Bureau's service of legislative districts, all you need to do is include the lat/lon in the geometry parameter being sent in the REST query. Then specify geometryType=esriGeometryPoint and spatialRel=esriSpatialRelWithin.

I'm not sure how you're getting the lat/lon, maybe from a click or manual input, but once you have those values, just swap them into the geometry definition in the query:

geometry={"x" : lon, "y" : lat, "spatialReference" : {"wkid" : 4326}}