GeoJSON and KML Merger: Combine Multiple Map Files Online
This free online map file merger lets you combine multiple GeoJSON and KML files into a single download — directly in your browser, with no software to install. Mix formats freely: drag in a GeoJSON from QGIS, a KML from Google Earth, and another GeoJSON from Mapbox, and merge them all into one clean file. Each source file is colour-coded on the map so you can see exactly what you are combining before you download.
GeoJSON and KML File Merger
Drag and drop your files below — add as many as you need, in any combination of GeoJSON and KML.
How to Merge GeoJSON and KML Files
Loading Your Files
Drag and drop one or more files onto the upload area, or click it to browse. You can add files one at a time or select several at once. Each file you add appears in the list below the drop zone with a colour swatch, feature count, and a summary of the geometry types it contains. You can remove individual files from the merge at any time by clicking the × button next to them.
Supported input formats:
- GeoJSON (.geojson or .json) — exported from QGIS, ArcGIS, Mapbox, Felt, overpass-turbo, or any web mapping tool
- KML (.kml) — exported from Google Earth, Google My Maps, or any GIS application that supports KML output
You can mix formats freely. A KML file from Google Earth and a GeoJSON file from QGIS can be merged together in a single operation.
Previewing on the Map
Every file you load is immediately rendered on the map in its own colour. This gives you a visual check of what you are combining before you commit to the download — useful for catching duplicate features, mismatched coordinate systems, or files loaded in the wrong order.
The Source Tag Option
The Tag each feature with its source filename option is enabled by default. When active, it adds a _source property to every feature in the merged output recording which file it originally came from. This makes it straightforward to filter or style by source in QGIS, Mapbox, or any GIS tool after the merge. Uncheck it if you want a clean output with no extra properties added.
Downloading the Merged File
Click Save merged GeoJSON to download a single .geojson file containing all features from all loaded files. Click Save merged KML to download a .kml file that opens directly in Google Earth or Google My Maps. Both formats preserve the original feature properties from every source file.
When Would You Need to Merge Map Files?
Splitting spatial data across multiple files is common, and there are many situations where you need to bring them back together:
- Combining data from different sources — you have boundary data in GeoJSON from one dataset and point locations in KML from Google My Maps, and you need both in a single file for analysis or upload
- Reassembling tiled exports — some tools export large datasets split across multiple files by region or feature type
- Consolidating field data — multiple surveyors each saved their own KML or GeoJSON and you need one combined dataset
- Preparing data for upload — platforms like Mapbox, Felt, or Google My Maps are easier to work with when all your features are in one file
- Merging historic snapshots — combining GeoJSON exports taken at different times into a single archive
Mixing GeoJSON and KML in the Same Merge
One of the most common workflows this tool supports is combining files that come from different applications. Google Earth and Google My Maps export KML. QGIS, ArcGIS, Mapbox, and most web GIS tools export GeoJSON. If your data is spread across both formats, you previously had to convert one format to the other before combining. This tool handles the conversion automatically — load any mix of GeoJSON and KML files and download a single merged GeoJSON or KML.
Output Formats
Merged GeoJSON
The output is a standard GeoJSON FeatureCollection containing all features from every loaded file. It is compatible with QGIS, ArcGIS, Mapbox, Felt, kepler.gl, and virtually any modern GIS or web mapping tool. If the source tag option is enabled, each feature will have a _source property you can use for filtering or styling.
Merged KML
The output is a valid KML file with all features wrapped in a single Document element. It opens directly in Google Earth and Google My Maps. Feature names from the original files are preserved where available.
Frequently Asked Questions
Can I merge a KML file and a GeoJSON file together?
Yes. The tool accepts both formats simultaneously. Drop in a .kml and a .geojson at the same time and it will merge all features into a single output file in whichever format you choose to download.
How many files can I merge at once?
There is no hard limit. The tool processes files entirely in your browser, so performance depends on your device and the total size of the files. Most typical GeoJSON and KML files merge instantly.
Will it work with large GeoJSON files?
Yes, though very large files (tens of megabytes) may take a moment to parse and render on the map. The merge operation itself is fast since it is simply combining feature arrays.
Does it change my feature properties?
No properties are removed or modified. If the source tag option is enabled, a single _source property is added to each feature. Turn it off if you want the output to be identical to the input files with no additions.
Can I remove a file after loading it?
Yes. Click the × button next to any file in the list to remove it. Its features will disappear from the map and it will be excluded from the merge.
Is my data uploaded to a server?
No. All processing happens in your browser. Your files are never sent anywhere. Closing the tab clears everything.
What coordinate system does the output use?
GeoJSON is always in WGS84 (EPSG:4326) by specification, and KML uses WGS84 by default. The tool does not reproject data, so all input files should be in WGS84. If your data is in a projected coordinate system, reproject it to WGS84 first in QGIS or using the MapScaping geometry converter.
Can I merge more than two files?
Yes — there is no limit on the number of files. Add as many as you need. Each one appears in the list with its own colour on the map.
[Continuar leyendo en Mapscaping](https://mapscaping.com/geojson-and-kml-merger/) ### Contexto para la comunidad GIS Esta información es relevante para profesionales de geoprocesamiento, analistas espaciales y usuarios de herramientas como QGIS, ArcGIS y PostGIS.