FlatGeobuf to GeoJSON
LocalConvert FlatGeobuf (.fgb) to GeoJSON in your browser — free, no sign-up, nothing uploaded. Feature count, bbox summary and map preview.
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Supports FGB
Choose fileFlatGeobuf (.fgb) → GeoJSON, locally in your browser.
What is it? FlatGeobuf to GeoJSON converts a FlatGeobuf (.fgb) file into GeoJSON, with a feature/geometry-type/bbox summary and a map preview of the result.
TL;DR: FlatGeobuf to GeoJSON parses a single-layer .fgb vector file into GeoJSON. Drop a file — conversion runs automatically — then check the feature count, geometry types and bounding-box summary on the map preview before copying or downloading. Free with no sign-in; local, nothing is uploaded.
How to use
- Drop a .fgb file into the dropzone — conversion starts automatically.
- The GeoJSON text appears in the output area when reading finishes, with a summary of feature count, geometry types and bounding box.
- Check the data on the map preview, then copy the text or download it as a .geojson file.
FAQ
Is it local?
Yes, parsing is local.
Are properties kept?
Yes, all attributes are preserved.
Are coordinates reprojected?
No — coordinates are written as-is from the FlatGeobuf. Reproject first (e.g. with QGIS or GDAL ogr2ogr) if you need a different CRS.
What is FlatGeobuf (.fgb)?
FlatGeobuf is a compact binary encoding for geographic data built on flatbuffers; a single .fgb file holds one layer of Simple Features and can carry a packed Hilbert R-tree index for fast bounding-box filtering. It is supported by GDAL/OGR, QGIS, GeoServer and PostGIS. This tool reads the whole file and writes it out as GeoJSON.
How large a .fgb file can I convert?
There is no upload limit because nothing is uploaded — the real bound is your device's memory, since the whole file is parsed in the browser. The map preview samples the first 5,000 features; the download always contains every feature.
Why is the GeoJSON output much bigger than my .fgb file?
That is expected, not an error. FlatGeobuf is a compact binary format with repeated headers compressed away, while GeoJSON is verbose text that repeats the coordinate structure per feature — plan for the output to be several times larger.
Examples
- Drop in a .fgb → the output area shows the feature/geometry-type/bbox summary and GeoJSON text → check the map preview → copy or download .geojson
Supported formats
Limitations
- In-browser conversion is bounded by device memory.
- No reprojection — coordinates are written as-is from the file.
- A .fgb file contains a single layer.
- The map preview renders geometry locally; CARTO basemap tiles are fetched over the network. Previews sample the first 5,000 features — downloads contain all of them.
Privacy
Privacy first: this tool runs entirely in your browser — your input and files never leave your device, and everything is cleared when you close the page.