Paul Ramsey • Apr 14, 2015

OGC Web Map Server support in CartoDB

WMS! What, more stuff? We make software, with map standards: Web Map Server. That is to say, CartoDB now offers the possibility of making its visualizations viewable via the Open Geospatial Consortium (OGC) Web Map Server (WMS) and Web Map Tile Service (WMTS) standards. The newest, hippest maps on the web just got “old school”.

CartoDB maps are available in a number of ways: through shared links, with embeds, using the CartoDB.js library, and via the Maps API. But there is a lot of software in use that pre-dates CartoDB, and by adding support for WMS/WMTS to CartoDB, we’ve opened up our maps to that software too.

This functionality comes with our Enterprise offering, if you want it activated please contact us.

So now you can add a CartoDB layer to your ArcGIS project.

Or to your QGIS project. (Actually, there is also a QGIS plug-in for CartoDB that is even more full-featured.)

Or to any other mapping software that supports WMS.

This could be of particular interest for data publishers that need to comply with OGC standards when publishing data, like for example in Europe with the INSPIRE initiative.

Finally, for those users coming to CartoDB from Google Maps Engine this could be a very important addition to have a successful migration.

How it Works

Once the add-on is activated on your account, just use the standard WMS end point for your account (where “user” is your account name) and plug it into your software:

https://user.carto.com/api/v2/wms/service

For WMTS connections, use the WMTS capabilites URL:

https://user.carto.com/api/v2/wms/wmts/1.0.0/WMTSCapabilities.xml

Or, if you are building WMS requests by hand, send them to the end point as usual. For example, for a listing of available layers, use a GetCapabilities request:

https://user.carto.com/api/v2/wms/service/?Version=1.1.1&Request=GetCapabilities

Or for a map rendering of a layer, use a GetMap request:

https://user.carto.com/api/v1/wms?Version=1.1.1&Request=GetMap&Layers=layername&Styles=&SRS=EPSG:4326&BBOX=-180,-85.05,180,85.05&Width=400&Height=200&Format=image/png

The WMS support for CartoDB has a few limitations that are important to keep in mind, for example:

• Spatial reference systems supported are only ESPG:4326 (geographic) and EPSG:3857 (Web Mercator).
• Compositing by requesting multiple layers in one GetMap request will not work. Each request can only address one layer at a time.
• Rendering is carried out by merging tiles from the CartoDB tile cache, which can result in some odd effects, particularly in EPSG:4326 where labels and symbols may appear slightly squashed, especially at higher latitudes.

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Strategic Advisor

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