File Conversion
Convert FGB to GeoJSON online
Convert FlatGeobuf — a fast, streamable binary format built for large datasets — into GeoJSON, which is the open, web-native JSON format read by Leaflet, Mapbox and virtually every modern GIS tool. Drop your FGB file below, GeoJSON is already selected as the output, and download the result. Everything runs in your browser and the cloud; you never install anything.
Upload your file
Drag and drop it into the converter below — no account needed to start.
Convert in the cloud
MapGO detects the format and produces your download in seconds.
Download & keep it
Files are deleted automatically after 48 hours.
Files are deleted automatically after 48 hours. Your files are never shared.
Why convert FGB to GeoJSON with MapGO?
Most online converters take one file and hand back one file. MapGO is built on a real geospatial engine, so a single upload can do more:
- Several outputs in one upload — tick GeoJSON and any other formats you need; every selected format is delivered from the same file.
- Files up to 5 GB — far beyond the browser-based converters that choke past a few hundred megabytes.
- Reproject while you convert — set a source and target EPSG code and the coordinate system is changed during the conversion, no second tool needed.
- Private by default — files are deleted automatically after 48 hours.
FGB vs GeoJSON at a glance
| FGB | GeoJSON | |
|---|---|---|
| Typical use | Large datasets streamed to web maps; cloud-native data pipelines | Web maps and APIs (Leaflet, Mapbox, D3); human-readable data in git |
| Size on disk | Compact binary with a built-in spatial index | Verbose plain text — the largest of the common formats, but gzips well |
| Attribute support | Full attribute tables | Flexible JSON properties — nesting and arrays allowed |
| Software support | GDAL/QGIS, plus web libraries via the flatgeobuf JS package | Every modern GIS tool and every web mapping library |
| Web-friendliness | Excellent — streams over plain HTTP range requests | Excellent — the native format of web mapping |
Other ways to convert FGB to GeoJSON
You don't need an online tool for this. If you have GDAL installed, one command does it:
ogr2ogr -f "GeoJSON" output.geojson input.fgbIn QGIS (free): open your FGB via Layer → Add Layer, then right-click the layer → Export → Save Features As… and pick GeoJSON as the format.
The MapGO converter above is for when you don't want to install anything, need to convert to several formats at once, or are handling files too large for a desktop machine — drop the file and download the result.
FGB to GeoJSON: frequently asked questions
Is the FGB to GeoJSON converter free?
Yes — new accounts get free conversion credits to start, and every paid plan converts unlimited files within its size limit. There is nothing to install; the whole FGB-to-GeoJSON conversion runs in the cloud.
Is my data kept private?
Conversion is fully automated and your file is never shared. Files are deleted automatically after 48 hours. Download your GeoJSON result and it's yours to keep.
What does the GeoJSON output contain?
You get a clean GeoJSON file with your geometry and attributes preserved, ready to open in the tools that read GeoJSON.
Why is the output so much bigger than my .fgb file?
FlatGeobuf is a compact binary format, while text formats like GeoJSON spell everything out — a size increase after conversion is normal and the data is identical. Gzip the text output when serving it and most of the difference disappears.
Which coordinate system will the GeoJSON output use?
By default the output keeps your source coordinate system; pick EPSG:4326 (WGS84) as the target if you want spec-standard GeoJSON that works immediately in Leaflet, Mapbox and other web libraries. MapGO reprojects during the conversion — no separate step needed.
Can I convert GeoJSON back to FGB?
Yes — use our GeoJSON to FGB converter for the reverse direction. MapGO supports conversions in both directions between these formats.