Delivering data for The National Map

The National Map aims at delivering current, nationwide views of regional and local data, synthesized into a single presentation. A key method of achieving this is the use of satellite data, aerial photographs, and derivative products to maintain up-to-date maps. The Earth Resources Observation Systems (EROS) Data Center (EDC) archives several large orthoimagery datasets, along with reference datasets, and is the main distributor of elevation data for this effort.

The EDC is using the raster and reference datasets to create OpenGIS Consortium and ArcGIS** compatible map services. The datasets are processed into seamless tables within an Arc Spatial Database Engine residing on an Oracle database. This database resides on a Solaris server accessed through an Arc Internet Map Server running on Windows 2000 machines to create online map services. A Cisco switch that uses load balancing for reliability handles client requests.

This system has a theoretical capacity to render of 300,000 to 400,000 images and to provide 600 to 1,500 data extractions per day. Over the last 6 months, this system has delivered more than 4.8 million maps online and 2.6 terabytes of actual data in downloads and media.