geojson-merge

Merge multiple GeoJSON files into one FeatureCollection.

install

$ npm install --save @mapbox/geojson-merge

API

merge

Merge a series of GeoJSON objects into one FeatureCollection containing all features in all files. The objects can be any valid GeoJSON root object, including FeatureCollection, Feature, and Geometry types.

Parameters

• inputs Array<Object> a list of GeoJSON objects of any type

Examples

var geojsonMerge = require('@mapbox/geojson-merge');

var mergedGeoJSON = geojsonMerge.merge([
  { type: 'Point', coordinates: [0, 1] },
  { type: 'Feature', geometry: { type: 'Point', coordinates: [0, 1] }, properties: {} }
]);

console.log(JSON.stringify(mergedGeoJSON));

Returns Object a geojson FeatureCollection.

mergeFeatureCollectionStream

Merge GeoJSON files containing GeoJSON FeatureCollections into a single stream of a FeatureCollection as a JSON string.

This is more limited than merge - it only supports FeatureCollections as input - but more performant, since it can operate on GeoJSON files larger than what you can keep in memory at one time.

Parameters

• inputs Array<string> a list of filenames of GeoJSON files

Examples

var geojsonMerge = require('@mapbox/geojson-merge');

var mergedStream = geojsonMerge.mergeFeatureCollectionStream([
  'features.geojson',
  'otherFeatures.geojson'])

mergedStream.pipe(process.stdout);

Returns Stream output: a stringified JSON of a FeatureCollection.

cli

Options:

-s or --stream to use the high-performance streaming mode. This allows you to combine very large GeoJSON files. Streaming mode requires every GeoJSON file to contain a FeatureCollection at the top level.

$ npm install -g @mapbox/geojson-merge
$ geojson-merge file.geojson otherfile.geojson > combined.geojson

geojson-merge (for dummies)

Windows Instructions:

1. Start the node.js application
2. Open cmd.exe
3. Browse to a folder where you'd like geojson-merge installed
4. In cmd.exe type the install string from above
5. Wait patiently, it could take a moment to start
6. Use cd node_modules to change directory to the node_modules folder
7. For simplicity sake, move your .geojson files into this node_modules directory
8. Run this command to merge your files:

$ node geojson-merge file1.geojson file2.geojson > merged.geojson

Merging multiple files in a folder

$ geojson-merge folder/*.geojson > combined.geojson