GeoJSON Merge Tool

How GeoJSON Merging Works

This tool combines two GeoJSON FeatureCollections into a single FeatureCollection. All features from both inputs are included in the output, preserving their original geometries and properties. No spatial operations are performed — features are simply concatenated.

Paste GeoJSON into both input panels, then click Merge. If either input is a bare Geometry or single Feature, it is automatically wrapped in a FeatureCollection before merging.

When to Merge GeoJSON

• Combining data from multiple API responses into a single file
• Joining layers exported separately from QGIS or other GIS tools
• Aggregating regional datasets into a national dataset
• Combining different feature types (points, lines, polygons) into one collection

Merge vs. Union

Merging and union are different operations. Merging concatenates features — overlapping polygons remain as separate features. Union combines overlapping polygon geometries into a single merged shape. Use merge when you want to keep features distinct, and union when you want to dissolve overlapping boundaries.

Try It

Merge a collection containing Central Park with a collection containing Brooklyn Bridge and Times Square. Paste the first collection into Input A and the second into Input B:

GeoJSON{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": { "name": "Central Park" },
      "geometry": {
        "type": "Point",
        "coordinates": [-73.9654, 40.7829]
      }
    },
    {
      "type": "Feature",
      "properties": { "name": "Brooklyn Bridge" },
      "geometry": {
        "type": "Point",
        "coordinates": [-73.9969, 40.7061]
      }
    },
    {
      "type": "Feature",
      "properties": { "name": "Times Square" },
      "geometry": {
        "type": "Point",
        "coordinates": [-73.9855, 40.7580]
      }
    }
  ]
}

The merged output contains all three features in a single FeatureCollection. Each feature retains its original geometry and properties. The order is Input A features first, followed by Input B features. Use the feature counter to verify the result contains the expected number of features.

How It Works

The merge tool reads the features array from each input FeatureCollection and concatenates them into a new array. No coordinate transformations or spatial calculations are performed. If an input is a bare Feature or Geometry, it is first wrapped in a FeatureCollection before concatenation. The result is always a valid FeatureCollection regardless of input types.