Converting DWG to GeoJSON extracts the geometry of an AutoCAD drawing into the JSON format that web maps and modern geo tooling speak natively.
What is DWG?
DWG is AutoCAD’s native binary drawing format, created by Autodesk, and the de facto standard for CAD drawings such as site plans, survey data, and engineering designs.
A DWG file stores CAD entities — lines, polylines, arcs, circles, text, blocks, and dimensions — organized on named layers, together with drawing metadata and viewport settings. It is a closed, proprietary binary format that changes across AutoCAD releases, so reading it reliably requires licensed technology: GeoConvert uses the Open Design Alliance (ODA) engine, the same technology major CAD vendors build on. Converting DWG to GIS formats extracts the geometry and layer structure into features you can style and analyze.
What is GeoJSON?
GeoJSON is an open, JSON-based format for encoding vector geographic features and their attributes, standardized as RFC 7946 by the IETF.
A GeoJSON document is plain UTF-8 JSON built from Feature and FeatureCollection objects, each pairing a geometry (Point, LineString, Polygon, and their Multi* variants, or a GeometryCollection) with a free-form "properties" object. Because it is human-readable text, it works well with version control, text diffing, and any JSON tooling, and it is the de facto interchange format for web maps and JavaScript libraries such as Leaflet, Mapbox GL, and OpenLayers. Unlike Shapefile it imposes no field-name length limit, mixes geometry types freely within one collection, and stores everything in a single file.
Why convert DWG to GeoJSON?
GeoJSON is the fastest route from a CAD drawing to Leaflet, Mapbox GL, or any JavaScript mapping stack, and to JSON-based data pipelines. Converting lets developers and analysts inspect CAD geometry in web tools, diff it in version control, and feed it to APIs without touching desktop CAD software.
Coordinate systems
Like DXF, a DWG drawing carries no coordinate reference system — coordinates are plain model units in whatever local or projected system the drawing was authored in. Converting to GIS usually means assigning the correct source CRS so the geometry lands in the right place on the map.
Per RFC 7946, coordinates are longitude/latitude in decimal degrees on the WGS84 datum (EPSG:4326), and the specification removed the older "crs" member, so a compliant GeoJSON file is always assumed to be WGS84. Coordinate order is [longitude, latitude], optionally followed by elevation.
What to watch out for
- GeoJSON is WGS 84 longitude/latitude by specification, and DWG has no CRS — assigning the correct source CRS is what makes the reprojection to WGS 84 meaningful.
- Drafting-only entities (dimensions, hatches, title blocks) are not map features and either drop out or arrive as bare geometry.
- Curved entities such as arcs, circles, and splines are approximated as line segments in GeoJSON, which has no native curve geometry.
- Very large drawings produce large text files; GeoJSON trades compactness for readability.
Frequently asked questions
- Why do my coordinates need a source CRS?
- GeoJSON is always WGS 84 longitude/latitude. A DWG stores plain model units with no projection metadata, so the converter must know which real-world system those units are in before it can reproject them correctly.
- Do arcs and circles survive?
- They are densified into line-segment approximations, because GeoJSON has no curve primitives. The visual shape is preserved within a small tolerance.