The Catalog Web Service (CSW) is an OGC standard (Open Geospatial Consortium) that allows you to discover, search and query metadata related to geographic data, services and resources. To publish metadata conforming to this standard, metadata is recorded according to the vendor information model; such models include descriptions of spatial references and thematic information. In this way, client applications can search geospatial data and services in very efficient ways.

The Catalog Web Service supports the use of query languages to find and return results using content models known as metadata schemas and encodings.