Upload a CSV with coordinates, pick a set of polygons, and download your CSV with the matched polygon attributes appended. Nothing is uploaded to a server — all processing happens locally in your browser.
01 · Input
Your CSV with point coordinates
Rows should contain latitude and longitude (in decimal degrees). You'll map the columns after upload.
02 · Geography
Polygons to join against
Pick a preset boundary, upload your own GeoJSON or zipped shapefile, or fetch one from a URL.
If none are checked, all properties will be added.
Each point will be tested against every polygon. Points that fall inside a polygon get that polygon's attributes; unmatched points keep blank values.
Done
Note: All points are plotted on the map, but the default view is framed on your polygons. If any unmatched points have coordinates far outside that area, zoom out or pan to find them.