The National Geologic Map Database Catalog is a free index to maps and geospatial data related to the geological sciences. A cooperative project of the Association of American State Geologists and the US Geological Survey (USGS), it indexes maps and geospatial data on geology, geophysics, marine geology, geologic resources, and hazards for the US and its territories published from the 1880s to the present. Currently the catalog provides access to 90,000-plus publications.
The National Space Science Data Center serves as the permanent archive for NASA space science mission data. "Space science" means astronomy and astrophysics, solar and space plasma physics, and planetary and lunar science. As permanent archive, NSSDC teams with NASA's discipline-specific space science "active archives" which provide access to data to researchers and, in some cases, to the general public.
The OldMapsOnline Portal is an easy-to-use gateway to historical maps in libraries around the world.
It allows the user to search for online digital historical maps across numerous different collections via a geographical search. Search by typing a place-name or by clicking in the map window, and narrow by date. The search results provide a direct link to the map image on the website of the host institution.
The Sloan Digital Sky Survey (SDSS) is one of the most ambitious and influential surveys in the history of astronomy. Over eight years of operations (SDSS-I, 2000-2005; SDSS-II, 2005-2008), it obtained deep, multi-color images covering more than a quarter of the sky and created 3-dimensional maps containing more than 930,000 galaxies and more than 120,000 quasars.
SDSS data have been released to the scientific community and the general public in annual increments, with the final public data release from SDSS-II occurring in October 2008. That release, Data Release 7, is available through this website.