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Processed locally — your file never leaves your device

GeoJSON Convex Hull

Wrap GeoJSON, KML or GPX features in their convex hull — the tightest enclosing polygon, computed in your browser.

Drop a GeoJSON, TopoJSON, KML, KMZ, GPX, zipped Shapefile or CSV file hereor click to choose a file from your deviceNothing is uploaded — the file is detected and processed entirely on your device.

How it works

  1. Select or drop a .geojson, .kml or .gpx file.
  2. Click Convex Hull to compute the enclosing polygon locally.
  3. Preview it on the map and download it as GeoJSON.

Frequently asked questions

What is a convex hull?
The smallest polygon that contains all your features and has no inward dents — the shape a rubber band would take if stretched around every point.
How is it different from a bounding box?
A bounding box is always an upright rectangle. A convex hull follows the actual outline of your data, so it's a much tighter fit for anything that isn't rectangular.
Is my file uploaded anywhere?
No. The hull is computed on your device with Turf.js.
What if my data has fewer than three points?
A hull needs at least three distinct points to enclose an area. With fewer, there's no polygon to produce and the tool says so rather than returning something misleading.