Spatial Join
Join polygon properties onto GeoJSON point features using point-in-polygon containment entirely in the browser.
Input
When polygons overlap, the first containing polygon is used and a warning identifies ambiguous matches.
Review these warnings
GeoJSON
Map preview
Understanding Spatial Join
Spatial relationships and derived geometry
Join polygon properties onto GeoJSON point features using point-in-polygon containment entirely in the browser.
Spatial Join evaluates where features lie relative to one another or creates geometry from that relationship. Geometry validity, boundary rules and compatible coordinate assumptions control the result.
How to verify the operation
When polygons overlap, the first containing polygon is used and a warning identifies ambiguous matches.
Review Spatial Join with feature counts, empty outputs, boundary cases and a few known examples. Confirm units and CRS assumptions before treating the result as authoritative.