The **SeaDataNet CDI OGC WMS service** provides an endpoint for visualization of CDI metadata on a map. It can be used to add CDI metadata locations into a (web)GIS application, possibly in combination with the CDI WFS service. The SeaDataNet infrastructure links more than 100 national oceanographic data centres and marine data centres from 35 countries bordering all European seas. The data centres manage large sets of marine and ocean data (such as samples, timeseries, profiles, trajectories, etc), originating from their own institutes and from other parties in their country, in a variety of data management systems and configurations. The CDI service itself provides access to the data resources from more than 800 data originators. The Common Data Index service (CDI) gives users, via an ISO19115 - ISO19139 based index (metadatabase), a highly detailed insight in the availability and geographical spreading of marine data from the different data centres across Europe. Data sets are available in ODV (Ocean Data View) and NetCDF (CF) SeaDataNet formats that can be imported to ODV software, which includes the Data Interpolating Variational Analysis software tool (DIVA).