I've been looking around and can't seem to find a good example for this, most likely because I'm not looking in the right places. I have a FeatureSet with Longitude and Latitude coordinates (and other data not related to location) that I'd like to compare to a FeatureLayer of polygons (districts in our service territory) to see which features from the FeatureSet fall within which polygon in the FeatureLayer. Then I'd ultimately like to be able to add the district number or name to the FeatureSet data.
This is all being done with ArcGIS Online, but I'm not against creating local temporary files to store things in if necessary.
Just need a bit of direction.