Converting DWG to Shapefile turns a native AutoCAD drawing into the classic Esri multi-file set (.shp/.shx/.dbf/.prj) that every desktop GIS reads.
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 Shapefile?
The Shapefile is a widely used vector data format developed and published by Esri, stored as a set of sibling files that share a common base name.
A single "shapefile" is really a bundle: the mandatory .shp (feature geometry), .shx (a shape index for fast seeking), and .dbf (a dBASE table of attributes), usually alongside a .prj (coordinate system) and sometimes a .cpg (attribute encoding). It is the lingua franca of desktop GIS and is read by virtually every tool, from ArcGIS and QGIS to GDAL/OGR. Its age shows in several hard limits: DBF attribute field names are truncated to 10 characters, each file component is capped at 2 GB, every file holds a single geometry type, and attribute types are constrained to what DBF supports (limited-width text, numbers, dates, and booleans).
Why convert DWG to Shapefile?
Survey drawings, site plans, and as-built documentation usually arrive as DWG, while GIS analysis, agency submissions, and web-map pipelines expect Shapefile. Converting extracts the drawing’s lines, polylines, and points into georeferenced features, with CAD layer names preserved as an attribute. It bridges the CAD-to-GIS handoff that otherwise requires a seat of AutoCAD plus a GIS.
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.
The coordinate reference system lives in the optional .prj sidecar as a WKT (well-known text) string. When the .prj is absent the CRS is genuinely unknown and consumers typically fall back to assuming WGS84, which can silently misplace data that was in another projection.
What to watch out for
- DWG carries no coordinate reference system — you usually need to assign the drawing’s real-world CRS (for example a UTM zone or a national grid) so the geometry lands in the right place.
- A Shapefile holds one geometry type per file, so a drawing mixing points, lines, and polygons is split by geometry type.
- CAD entities such as text, dimensions, and complex blocks do not map cleanly onto GIS features; expect geometry and layer names to survive, not drafting annotations.
- DWG has no attribute table — attributes in the output are limited to what the drawing structure provides (layer, entity type).
Frequently asked questions
- Why does DWG conversion need a server?
- DWG is a proprietary Autodesk binary format. Reading it reliably requires the licensed ODA engine — a native library that cannot run inside a browser, unlike the open formats GeoConvert converts client-side.
- Will my CAD layers survive?
- Yes — each feature records the layer it came from, so you can filter and style by the original CAD layer structure in your GIS.
- My drawing uses local site coordinates. What CRS do I pick?
- If the drawing was authored in a projected system (a UTM zone, a state plane, a national grid), assign that as the source CRS. Truly local/arbitrary site coordinates cannot be georeferenced automatically — they need a known transformation first.