Convert FlatGeobuf to DXF Online — Free GIS Converter

GIS datasets stored in FlatGeobuf can be brought into AutoCAD, Civil 3D, and other CAD environments as DXF — convert your .fgb file to .dxf for engineering design and CAD integration with geodata.plus.

Why convert FlatGeobuf to DXF?

Engineers and surveyors working in AutoCAD or Civil 3D regularly need to reference GIS data — cadastral boundaries, topographic contours, utility networks, and land-use zones — as a background reference or starting geometry for their designs. GIS teams that maintain authoritative datasets in modern formats like FlatGeobuf need a reliable way to export those datasets to DXF so they can be consumed by CAD workflows without manual retracing.

Converting FlatGeobuf to DXF also enables round-trip workflows: a surveyor exports a site boundary from CAD as DXF, a GIS analyst processes and attributes it in a GIS pipeline, stores the result as FlatGeobuf, and then exports back to DXF for the next round of CAD design work.

Why use geodata.plus

• Free tier — convert up to 3 files per month at no cost, no credit card required
• Automatic CRS detection — reads the CRS from the FlatGeobuf header; you can specify the target CAD coordinate system for reprojection
• Optional reprojection — reproject to any projected CRS (e.g., a state plane or national grid) that matches your CAD project setup
• Browser-based — no AutoCAD, GDAL, or QGIS install needed; works on any modern browser
• Encrypted transfer — all uploads use TLS; files are stored temporarily in Cloudflare R2 and automatically deleted on schedule
• Auto-deleted output — output files are automatically deleted after 2 days (free tier) and 7 days (Pro); no manual cleanup needed

How it works

1. Upload your FlatGeobuf file (.fgb) using the widget above
2. geodata.plus reads the CRS, geometry type, and attribute schema from the FlatGeobuf header
3. Select DXF as the output format; optionally reproject to the projected CRS used in your CAD project
4. Download your .dxf file ready to open in AutoCAD, Civil 3D, MicroStation, or BricsCAD

FlatGeobuf format

FlatGeobuf is a binary, row-oriented vector format built on FlatBuffers, with an embedded Hilbert R-tree spatial index for fast bounding-box queries. The CRS is stored in the file header alongside the feature schema. It supports all OGC geometry types and typed attribute columns with no field name length restrictions. FlatGeobuf is the preferred format for serving large vector datasets from object storage over HTTP.

| Property | Value | |---|---| | Extension | .fgb | | Type | Vector, single file (binary) | | Coordinate system | Any CRS (stored in header) | | Geometry types | Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, GeometryCollection | | Common software | GDAL, QGIS, Mapbox, cloud-native GIS, web APIs |

DXF format

DXF (Drawing Exchange Format) is Autodesk's open CAD interchange format, introduced in 1982. It organizes geometry as named layers of entities — points, lines, polylines, arcs, circles, and polygon hatches. DXF has no native CRS metadata; coordinates are in whatever space the CAD project uses. DXF is read and written by virtually every CAD application on the market and is the dominant format for exchanging engineering drawings between organizations.

| Property | Value | |---|---| | Extension | .dxf | | Type | Vector, single file | | Coordinate system | None native — local/project coordinates assumed | | Geometry types | Points, Lines, Polylines, Arcs, Circles, Polygons (hatches) | | Common software | AutoCAD, Civil 3D, MicroStation, BricsCAD, surveying tools |

Frequently asked questions

How are FlatGeobuf attribute columns represented in the DXF output?

DXF does not have a native attribute table equivalent to a GIS DBF. geodata.plus writes FlatGeobuf attributes as DXF entity XDATA (extended data) and, where applicable, as block attributes if the geometry is output as a block insertion. Key attributes like feature name or ID can also be written as DXF text entities placed at the feature centroid on a dedicated annotation layer.

What happens to GeoJSON polygon features when converted to DXF?

Polygon features (including holes/interior rings) are output as closed polylines in DXF. Exterior rings become outer polylines; interior rings (holes) are output as separate inner polylines on the same layer. This is the standard representation for polygons in DXF-based CAD workflows.

My FlatGeobuf is in WGS 84 — what CRS should I reproject to for my CAD project?

This depends on your CAD project's coordinate system. For civil engineering projects in the US, a state plane CRS (e.g., EPSG:2264 for North Carolina State Plane) or a UTM zone is typical. Your CAD project properties will show the current coordinate system. Enter its EPSG code in geodata.plus during conversion to ensure the DXF coordinates align correctly when imported into your drawing.