Convert DGN to TOPOJSON Online - Free & Fast

What is DGN?

DGN (Design) is the native file format of Bentley Systems MicroStation, used for storing CAD drawings and GIS data in infrastructure projects such as roads, bridges, and utilities, supporting 2D and 3D design elements with level-based organization.

What is TOPOJSON?

TopoJSON is an extension of GeoJSON that encodes topology, sharing boundary arcs between adjacent features to dramatically reduce file size for map data.

When Should You Use DGN vs TOPOJSON?

DGN vs TOPOJSON: Key Differences

• •The core technical difference: DGN relies on lossy compression whereas TOPOJSON uses lossy compression.
• •Since both DGN and TOPOJSON use lossy compression, the quality characteristics are comparable — differences in file size come down to how efficiently each format implements compression.
• •How transparency is handled: TOPOJSON does not support alpha channels — transparent areas in the source will become opaque.
• •File sizes: DGN files typically range 100KB to 1GB depending on design complexity and TOPOJSON files 80% smaller than equivalent GeoJSON for administrative boundaries.
• •DGN is optimized for civil engineering, infrastructure mapping, transportation gis while TOPOJSON is designed for web choropleth maps, data visualization, boundary simplification — choose based on your specific workflow needs

Advantages of DGN

• ✓DGN uses lossy compression tailored for Civil engineering, infrastructure mapping, transportation GIS.
• ✓DGN is supported natively on virtually every device, browser, and operating system.
• ✓DGN files are compact and quick to transfer, even over slow connections.
• ✓DGN integrates seamlessly with all major creative tools and workflows.

Advantages of TOPOJSON

• ✓TOPOJSON uses lossy compression tailored for Web choropleth maps, data visualization, boundary simplification.
• ✓TOPOJSON is supported natively on virtually every device, browser, and operating system.
• ✓TOPOJSON files are compact and quick to transfer, even over slow connections.
• ✓TOPOJSON integrates seamlessly with all major creative tools and workflows.

Common Use Cases for DGN to TOPOJSON Conversion

Industry Applications

Best Practices for DGN to TOPOJSON Conversion

• →When converting DGN to TOPOJSON: confirm the coordinate reference system (CRS / projection) is preserved or explicitly reprojected
• →Keep attribute tables and feature metadata intact — TOPOJSON should retain all fields from DGN
• →Check geometry types (point, line, polygon) map cleanly between the two formats
• →Verify that z/elevation values and topology survive the conversion when working with terrain data
• →Always keep a backup of your original files before converting
• →Choose the appropriate quality settings for your specific use case

Troubleshooting DGN to TOPOJSON Conversion

• !TOPOJSON features land in the wrong place after DGN to TOPOJSON → verify the CRS/projection; mismatched coordinate systems shift geometry
• !Attribute columns missing in TOPOJSON → some GIS formats have field name length or type limits; rename or cast columns first
• !DGN to TOPOJSON drops the z/elevation dimension → pick a target format that supports 3D geometry
• !TOPOJSON file won't open in your GIS app → confirm the format version and any required sidecar files (e.g. .prj, .shx) are present

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