Convert TOPOJSON to GML Online - Free & Fast

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.

What is GML?

GML (Geography Markup Language) is the OGC standard XML grammar for encoding geographic features with full coordinate reference system support.

When Should You Use TOPOJSON vs GML?

TOPOJSON vs GML: Key Differences

• •The core technical difference: TOPOJSON relies on lossy compression whereas GML uses lossless compression.
• •The switch from lossy compression to lossless compression means you preserve full quality at the expense of larger file sizes.
• •Alpha channel support: GML lacks transparency support.
• •File sizes: TOPOJSON files typically range 80% smaller than equivalent GeoJSON for administrative boundaries and GML files Larger than Shapefile due to verbose XML structure.
• •Use case fit: TOPOJSON targets web choropleth maps, data visualization, boundary simplification and GML targets ogc-compliant geospatial data exchange, enterprise gis — your choice depends on which workflow stage you are serving.

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.

Advantages of GML

• ✓GML applies lossless compression specifically calibrated for OGC-compliant geospatial data exchange, enterprise GIS.
• ✓GML enjoys broad native support across operating systems, browsers, and creative tools alike.
• ✓GML guarantees every bit of the original data survives — no approximations, no shortcuts.
• ✓You will find GML support built into virtually every tool that handles OGC-compliant geospatial data exchange, enterprise GIS — no plugins or converters needed.

Common Use Cases for TOPOJSON to GML Conversion

Industry Applications

Best Practices for TOPOJSON to GML Conversion

• →When converting TOPOJSON to GML: confirm the coordinate reference system (CRS / projection) is preserved or explicitly reprojected
• →Keep attribute tables and feature metadata intact — GML should retain all fields from TOPOJSON
• →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 TOPOJSON to GML Conversion

• !GML features land in the wrong place after TOPOJSON to GML → verify the CRS/projection; mismatched coordinate systems shift geometry
• !Attribute columns missing in GML → some GIS formats have field name length or type limits; rename or cast columns first
• !TOPOJSON to GML drops the z/elevation dimension → pick a target format that supports 3D geometry
• !GML 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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