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GeoJSON Area & Length
Measure the area, perimeter and length of every shape in GeoJSON, KML or GPX, with a map and a table.
Free, no uploads, no sign-up. Runs 100% in your browser.
How GeoJSON Area & Length works
Tracks are read and processed in your browser. The map is drawn on a canvas with no tiles by default, so not even your location area is sent anywhere. You can turn on an OpenStreetMap background if you want one. Areas use spherical excess on the WGS84 sphere, the same way common GIS libraries do, and holes are subtracted.
Input: GEOJSON, KML, KMZ, GPX. Output: CSV, GEOJSON.
How to use GeoJSON Area & Length
- Drop a file or paste GeoJSON.
- Read the totals and the table.
- Download the table or GeoJSON with area and length added to each feature.
Tips
- The map has no background tiles by default, so your location area is not sent anywhere. Turn on the map background if you want street detail.
- Most watches and apps export GPX. Look for Export or Share in the activity menu.
GeoJSON Area & Length FAQ
- Are my files uploaded?
- No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.
- Is it free? Are there limits or watermarks?
- Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.
- Does it work offline?
- Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.
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