Shows geographic relationship between device's most recent known location and the given region. If the device has no last-known location, no device location observation will be attached, and
confidence_in will be
0. The relation will always have a
geojson property of type
FeatureCollection which will contain at least the
Feature for the region. If a last known location exists for the device, the associated device location observation will be attached, and a feature will exist in the feature collection.