GeoJSON Convex Hull Calculator
Get the convex hull (minimum enclosing polygon) of GeoJSON points — with vertex count and geodesic area, computed locally in your browser. Free, no sign-in.
Processing and data safety
Section titled “Processing and data safety”This tool runs entirely in your browser — your files are never uploaded to a server.
Input and output
Section titled “Input and output”- Formats: GeoJSON
- Flow: GeoJSON points → minimum convex hull polygon
How to use
Section titled “How to use”- Paste GeoJSON points, load a .geojson/.json file via “or load a file”, or keep the sample that is already filled in.
- Click “Compute convex hull” (or press Ctrl/⌘+Enter).
- Check the vertex count / geodesic area summary, compare against the input on the map preview (“Show original”), then copy or download hull.geojson.
Key details and limits
Section titled “Key details and limits”- Needs at least 3 distinct points not all on one line — errors name the real cause (too few distinct points vs. all collinear).
- Convex hull only (no concave hull here).
- Output is the hull polygon itself (empty properties); input attributes are not kept.
Common use cases
Section titled “Common use cases”- Paste a point set → get the convex hull polygon with a vertex/area summary
- Paste 50 GPS track points → get the hull boundary with vertex count and area in km², verified against the input on the map before downloading.