EPSG.io

The EPSG.io service helps you discover coordinate systems from across the globe, view their parameters, and choose the most suitable transformations. The service is developed and maintained by the MapTiler team.

EPSG.io serves as a custom interface to the EPSG database, offering an extensive list of projections and coordinate systems, their bounding boxes, and transformation options to enhance the precision of coordinate transformations.

Contents:

• Discover coordinate systems
• Pick the right transformation
• Exporting coordinate reference systems
• Endpoints for coordinate reference systems
• MapTiler Coordinates API
  • Coordinates transformation
  • Coordinate system search
  • MapTiler API Key
  • MapTiler Client JS

Discover coordinate systems and their parameters

To explore coordinate reference systems, use the search bar at epsg.io. You can search for coordinate systems, datums, ellipsoids, units, transformation operations, and more. Enter the EPSG code (e.g., 3857) or part of a name (e.g., pseudo-mercator) to find what you need.

Pick the right transformation

Transformation parameters are often essential for improved accuracy, especially when the source and target coordinate reference systems use different ellipsoids. Applying the TOWGS84 parameter can significantly enhance precision, improving transformations from meters to centimeters.

Each projection that supports multiple transformations offers a list of options on its dedicated page, such as Swiss CH1903+ / LV95 (EPSG:2056). Try selecting a different transformation if your GPS data doesn't align with the local coordinate system.

Choosing the correct transformation is also crucial for reverse transformations, such as converting local coordinates back to WGS84 (EPSG:4326). This can also help when switching to a different coordinate system or achieving greater precision.

Exporting coordinate reference systems in GIS-compatible formats

Each coordinate reference system definition can be exported in various text formats compatible with transformation libraries and GIS tools, including OGC WKT, PROJ, ESRI WKT, PROJ4JS, GeoServer, MapServer, PostGIS, and more.

Example PROJ definition for the Pseudo Mercator CRS (EPSG:3857):

+proj=merc +a=6378137 +b=6378137 +lat_ts=0 +lon_0=0 +x_0=0 +y_0=0 +k=1 +units=m +nadgrids=@null +wktext +no_defs +type=crs

Example ESRI WKT definition for the Pseudo Mercator CRS:

        PROJCS["WGS_1984_Web_Mercator_Auxiliary_Sphere",
          GEOGCS["GCS_WGS_1984",
              DATUM["D_WGS_1984",
                  SPHEROID["WGS_1984",6378137.0,298.257223563]],
              PRIMEM["Greenwich",0.0],
              UNIT["Degree",0.0174532925199433]],
          PROJECTION["Mercator_Auxiliary_Sphere"],
          PARAMETER["False_Easting",0.0],
          PARAMETER["False_Northing",0.0],
          PARAMETER["Central_Meridian",0.0],
          PARAMETER["Standard_Parallel_1",0.0],
          PARAMETER["Auxiliary_Sphere_Type",0.0],
          UNIT["Meter",1.0]]
        

Endpoints for coordinate reference systems

You do not have to rely on the web interface. EPSG.io delivers endpoints that can be automated in applications.

https://epsg.io/{CODE}

https://epsg.io/{EPSG}-{CODE}

https://epsg.io/{EPSG}-{CODE}.{FORMAT}

https://epsg.io/{CODE}-{OBJECT}

https://epsg.io/?q=KEY:VALUE[+KEY:VALUE[+…]]

https://epsg.io/{VALUE}-crs-{CODE}

List of output formats

List of supported objects

Coordinates API by 

EPSG.io is custom, open, and free service provided by MapTiler. The coordinate transformation and search functionalities are powered by the MapTiler Cloud Coordinates API, which is fully compatible with EPSG.io and also offers a /transform API endpoint for coordinate transformation and /search API endpoint for searching through coordinate systems and it's components.

MapTiler's Coordinates API provides:

• Coordinate transformation and CRS search capabilities
• A stable, scalable service with 99.9% SLA for business plans
• Dedicated MapTiler API key for managing separate costs across applications
• Batch transformation up to 50 points.

Coordinates transformation

The universal transform URL format is:

https://api.maptiler.com/coordinates/transform/{COORDS}.json?s_srs={CODE}&to_srs={CODE}

Example coordinate transformation URL call:

https://api.maptiler.com/coordinates/transform/50,15.json?s_srs=4326&t_srs=5514&ops=1623

Coordinate system search

The universal search URL format is:

https://api.maptiler.com/coordinates/search/{QUERY}.json?PARAMS

Example coordinate search URL call:

https://api.maptiler.com/coordinates/search/swiss deprecated=0.json?exports=true&limit=5

MapTiler API Key

To use MapTiler API services, you must include your MapTiler API key in all API calls by appending &key=xxxxxxxxxxxxxxxxxxxx to the URL.

A custom API key is provided upon free registration to the MapTiler Cloud platform. For more details, read the MapTiler documentation.

MapTiler Client JS 

MapTiler Client JS is a JavaScript/TypeScript library designed for seamless integration with MapTiler services. It provides quick and easy access to the Coordinates API:

1. Install MapTiler SDK

   npm install --save @maptiler/client

2. Search coordinate reference system

   // in an async function, or as a 'thenable':
       const result = await maptilerClient.coordinates.search('mercator');

3. Transform coordinates

   const resultA = await maptilerClient.coordinates.transform([1, 45], {targetCrs: 9793})

Read more about the MapTiler Client JS for coordinates API.

OpenLayers 

OpenLayers simplifies embedding dynamic maps into web pages. It supports displaying map tiles, vector data, and markers from any source.

In addition to rendering, OpenLayers allows on-the-fly transformation of raster and vector data. Coordinate transformations are easily handled using the Proj4js definition powered by the MapTiler Coordinates API. For more details, visit the OpenLayers Proj4js documentation.

Read MapTiler Documentation to learn how to use OpenLayers with MapTiler maps and services.