GEOO.APP

S-57 to TopoJSON

Convert S-57 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 S57 to TOPOJSON format

Data Security

All processing is done locally in your browser

Standard Format

Output standard TOPOJSON format

s57 to topojson

Convert s57 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

S-57

S-57 is an electronic navigational chart (ENC) data exchange standard defined by the International Hydrographic Organization (IHO), the official data format recognized by the International Maritime Organization (IMO) for Electronic Chart Display and Information Systems (ECDIS). S-57 data contains nautical features including water depths, channels, anchorages, and obstructions, serving as the key data foundation for safe maritime navigation.

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

S-57: limitations to know

  • Specialized format primarily for maritime navigation
  • Data access typically requires authorization and payment

TopoJSON: what you gain

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

Why convert S-57 to TopoJSON?

Converting S-57 to TopoJSON is one of the most common workflows in GIS. S-57 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 S-57 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 S-57 to TopoJSON converter free?

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

Are coordinate systems preserved when converting S-57 to TopoJSON?

By default the output keeps the source coordinate system. If your S-57 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 S-57 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 S-57 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.