Processed locally — your file never leaves your device
GeoJSON Dissolve
Merge touching or overlapping polygons into single shapes, optionally grouped by an attribute — entirely 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
- Select or drop a .geojson or .kml file containing polygons.
- Optionally choose an attribute to group by, so only polygons sharing a value are merged.
- Click Dissolve to merge touching polygons locally and preview the result.
- Download the dissolved GeoJSON.
Frequently asked questions
- Is my file uploaded anywhere?
- No. The dissolve runs entirely on your device using Turf.js.
- What does dissolving by an attribute do?
- Only polygons sharing the same value for that attribute are merged. Two adjacent polygons in different regions stay separate, which is what makes it useful for building region outlines from smaller units.
- What happens to my attributes?
- A dissolved shape has no single source feature, so attributes are dropped — except the attribute you grouped by, which is kept. The tool states this explicitly rather than losing data silently.
- Why does dissolve fail on some files?
- Self-intersecting or otherwise invalid polygons make the underlying geometry library fail. Run Validate & Repair first — it reports self-intersections, degenerate rings and duplicate vertices.