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DGN to TopoJSON

Convert DGN to TopoJSON online for free — right in your browser. No upload, no sign-up, batch conversion, coordinate systems and attributes preserved.

Features

Fast Conversion

Efficiently convert from DGN to TOPOJSON format

Data Security

All processing is done locally in your browser

Standard Format

Output standard TOPOJSON format

dgn to topojson

Convert dgn to topojson online for free — right in your browser. No upload, no sign-up, batch conversion, coordinate systems and attributes preserved.

Drag and drop files or folders, or click to upload

Related Tools

About

DGN

DGN (Design) is the native design file format of Bentley Systems Microstation, widely used in infrastructure engineering (roads, bridges, pipelines) and architectural design. DGN files contain rich vector graphics, annotations, and reference information. Vector features from DGN can be extracted to standard GIS formats through the GDAL library.

TopoJSON

TopoJSON is a GeoJSON extension developed by Mike Bostock that encodes topology to eliminate redundant shared boundaries. Unlike GeoJSON where each polygon independently stores all vertices, TopoJSON uses arcs to share common boundaries between adjacent features, reducing file sizes by over 80%. TopoJSON is particularly suited for rendering large numbers of adjacent areas such as administrative district maps.

Conversion trade-offs

DGN: limitations to know

  • Proprietary format, parsing relies on third-party libraries like GDAL
  • Complex coordinate reference system handling

TopoJSON: what you gain

  • Dramatically reduces network transfer and storage requirements
  • Topological relationships support efficient geometric operations

Why convert DGN to TopoJSON?

Converting DGN to TopoJSON is one of the most common workflows in GIS. DGN data usually comes from desktop GIS software, government open-data portals, or data exchange with partners, while TopoJSON is what modern tools, web maps, and platforms expect. This converter bridges the two: it reads your DGN files, keeps geometry and attributes intact, and writes clean TopoJSON output — entirely in your browser, so your data never leaves your device.

Frequently asked questions

Are my files uploaded to a server?

No. The conversion runs entirely in your browser using WebAssembly — your files never leave your device.

Is the DGN to TopoJSON converter free?

Yes, completely free with no sign-up and no usage limits.

Are coordinate systems preserved when converting DGN to TopoJSON?

By default the output keeps the source coordinate system. If your DGN file uses a projected CRS (like UTM), you can search any EPSG coordinate system by keyword or code and reproject in one step. Note: output formats that require WGS84 by specification (KML, KMZ, GPX) always reproject to WGS84 automatically.

Can I convert multiple files at once?

Yes — drop several DGN files at once and each one produces its own TopoJSON output.

TopoJSON at a glance

Key Features

  • Topology encoding eliminates redundant vertices, file size 80%+ smaller than GeoJSON
  • Preserves topological relationships between features for adjacency analysis
  • Can be easily converted back to GeoJSON for rendering

Common Use Cases

  • Efficient rendering of large adjacent areas like administrative districts in web maps
  • GIS applications requiring topology analysis (adjacency, containment)

How to Use

  1. 1

    Upload your DGN file — drag and drop it onto the page, or browse from your device. You can add several files at once for batch conversion.

  2. 2

    The conversion runs automatically in your browser. No upload, no server — your data stays on your device the entire time.

  3. 3

    Download the TopoJSON file. Each input produces its own output, ready to use in your GIS, web map, or archive.