Convex Hull Generator
Upload any GeoJSON, KML, or GPX file and compute the convex hull — the smallest convex polygon that contains all features. Download as GeoJSON or KML.
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GeoJSON, KML, GPX — any geometry type
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What is a convex hull?
The convex hull of a set of features is the smallest convex polygon that encloses all of them. It is the two-dimensional equivalent of wrapping a rubber band around a collection of points — the band snaps into the tightest convex shape possible.
All vertices from all input features — whether points, lines, or polygon boundaries — are used to compute the hull. The result is always a single convex polygon, regardless of how many input features there are.
Common use cases
Dataset footprint
Generate a simple outline of a spatial dataset's extent for use in metadata records, spatial indexes, or overview maps.
Cluster boundary estimation
Approximate the boundary of a cluster of points or features for area estimation, spatial filtering, or reporting.
Input validation
Quickly check whether all features fall within an expected study area by comparing the hull to a known boundary polygon.
Spatial join preprocessing
Use the hull as a coarse pre-filter before running an expensive exact intersection — any features outside the hull cannot possibly intersect the data.
Frequently asked questions
What does "convex" mean in the context of a convex hull?
A shape is convex if, for any two points inside it, the straight line between them also lies entirely inside the shape. The convex hull is the smallest such shape that encloses all your features — imagine stretching a rubber band around them and letting it snap tight.
Will the convex hull work on polygons and lines, not just points?
Yes — all vertices from all features (points, lines, and polygons) are used to compute the hull. The output is a single polygon enclosing all input geometry.
What is the difference between a convex hull and a concave hull?
The convex hull is the tightest convex shape — it cannot curve inward. A concave hull allows indentations, following the outline of the dataset more closely. Use the Concave Hull Generator when the convex result is too loose for your dataset.
Can I get one hull per feature rather than one hull for the whole dataset?
This tool computes a single hull enclosing all features. To get per-feature hulls, process each feature separately by uploading individual files.