GIS Links

The National Map

The National Map is a collaborative effort between the USGS and other Federal, State, and local partners to provide geospatial information for the Nation. It is a great place to look for geographic information for any part of the nation. The geographic information available from The National Map includes orthoimagery (aerial photographs), elevation, geographic names, hydrography, boundaries, transportation, structures, and land cover. The National Map is a part of the National Spatial Data Infrastructure (NSDI) which is defined as the technologies, policies, and people necessary to promote sharing of geospatial data throughout all levels of government, the private and non-profit sectors, and the academic community.

SanGIS is proud to be one of the partner agencies with the USGS in maintaining the National Map. SanGIS is the designated data steward for the National Hydrography Dataset (NHD) for the County of San Diego. Through this partnership SanGIS collects, edits, and updates the NHD component of The National Map.

Check out the links below to learn more about The National Map.

The National Map Home Page
Starting point for getting to know and use The National Map. Contains links to all aspects of The National Map and related programs.
The National Map Viewer
An interactive program providing access to many of The National Map data layers.
The National Hydrography Dataset
Home page for the National Hydrography Dataset (NHD). The NHD is the surface water component of The National Map. SanGIS is a partner with USGS in maintaining the NHD for San Diego County.
NHD Data Viewer
The interactive National Map component for the National Hydrography Dataset