Examples of Geospatial Metadata Catalogs
Data.gov Data Catalog Note that only datasets marked as "Federal" are subject to the U.S. Federal Government and Data.gov's Data Policy. Non-federal participants (e.g., universities, organizations, and tribal, state, and local governments) maintain their own data policies. It is important that users understand the data policies of participating entities in order to best utilize these datasets. A description of this catalog and information about the datasets presented and associated metrics is available here: http://www.data.gov/newcataloginfo. catalog.data.gov//dataset
Geo.data.gov Since 2005 Geodata.gov has provided the largest web-based access at a single-point for maps, government data, and geospatial services—the Geospatial One Stop. Data.gov, launched in May 2009, provides access to over 400,000 (primarily geospatial) datasets from 172 agencies across the Federal government. On October 1, 2011, Geodata.gov moved to Geo.Data.gov, within the Data.gov infrastructure. http://geo.data.gov/geoportal/. This is now the data.gov catalog (see Data.gov Data Catalog above).
Data.gov Ocean Communities This is the National Ocean Council’s portal for data, information, and tools to support people engaged in planning for the future of the ocean, our coasts, and the Great Lakes. Their goal is to be a one-stop hub to support planners and to provide useful information to the public. Please visit their Forums to tell them what would make the site most useful to you as they expand their content. http://www.data.gov/communities/ocean
USGS Core Science Metadata The Core Science Metadata Clearinghouse contains standardized metadata descriptions of earth science data sets and information products. Metadata descriptions follow the Federal Geographic Data Committee's (FGDC's) Content Standards for Digital Geospatial Metadata. The Clearinghouse is also a participating node on the FGDC's National Spatial Data Clearinghouse (NSDI) and the Geo.Data.gov. The Core Science Metadata Clearinghouse is comprised of contributions from many different organizations to help scientists find a broad spectrum of data. Metadata in the Clearinghouse describes both geospatial and data that is not as explicitly geospatial, such as results of laboratory research. http://www.usgs.gov/core_science_systems/csas/metadata/discover_data.html
EPA Geospatial Gateway EPA's Environmental Dataset Gateway (EDG) can be used to find and access EPA's environmental resources. https://edg.epa.gov/metadata/catalog/main/home.page
NOAA has several Geoportal Instances. See the ESRI Geoportal page in this wiki for details.