Comprehensive /Informational Portals
A community of the many geospatial scientists within Consultative Group on International Agriculture Research (CGIAR). Serves Climate, Elevation, Socio-Economic, and Soils digital data sets.
Useful review of Earth distance calculation formulas, courtesy of the Australian Government (Geoscience Australia)
Free, customized earth science data. Holdings can be searched spatially, temporally,
or via keywords
Portal to a variety of open-source geospatial datasets
A planetary-scale platform for environmental data & analysis
The GCMD holds more than 25,000 Earth science data set and service descriptions, which cover subject areas within the Earth and environmental sciences.
This page contains links to a broad set of remote sensing data sources as well as informational and tutorial remote sensing web sites
Scientific stewardship, products, and services for sea floor and lake bed data
Home page for Natural Resources Canada / Earth Sciences Sector. Good sources of geospatial data for Canada.
Find a spatial reference for most map projections
Interactive portal gives access to a global geospatial data archive
Concise overview and map of Global Universe Transverse Mercator (UTM) Zones
Biogeochemical Data: Observations and Models
A NASA-sponsored source for biogeochemical and ecological data and models useful in
Geochemical analysis of sediment samples throughout the United States, collected by
the hydrogeochemical and stream sediment reconnaissance (HSSR) phase of the
National Uranium Resource Evaluation (NURE) program
Biological / Species Data
European Commission project aims to identify and catalogue those European ecosystems and environmental conditions that influence the spatial and temporal distribution and dynamics of human pathogenic agents.
A leading source for reliable scientific information about species and ecosystems of the Western Hemisphere. This site serves as a portal for accessing several types of publicly available biodiversity data.
Climate Data: Observations and Models
CRU Home Page: Portal to research descriptions and data set access
Intergovernmental Panel on Climate Change Data Distribution Center portal: provides climate, socio-economic, and environmental data for the past and projected future.
Information portal for NCAR: a federally funded research and development center devoted to service, research and education in the atmospheric and related sciences.
NCAR Community Earth System Model (CESM) Home Page  - Access to research tools and long-term simulation run datasets.
CGD research provides understanding of the Earth's climate system and uses models to develop the capability of predicting the evolution of the climate system to the degree possible.
One of the world's largest climate data archives.
Searchable repository of surface climate parameter measurements.
ESRL/PSD) addresses physical science questions of short- and long-term societal and policy relevance within NOAA's Climate and Weather and Water Goals, while conducting the physical process research necessary so that ESRL can help provide the nation with a seamless suite of information and forecast products ranging from short-term weather forecasts to longer-term climate forecasts and assessments.
Knowledge-based system uses point measurements of precipitation, temperature, and other climatic factors to produce continuous, digital grid estimates of monthly, yearly, and event-based climatic parameters.
World Climate Research Program/ Coupled Model Intercomparison Project (WCRP / CMIP3) 
(Registration required to download CMIP3 data sets)
This database covers most of Earth surface at 1 KM**2 spatial resolution.
Includes 19 climate measurements well-suited for use in ecological modeling.
Extensive archive of European socio-economic statistical data sets.
Forest Resource Data
The FIA Program reports on status and trends in forest area and location; in the species, size, and health of trees; in total tree growth, mortality, and removals by harvest; in wood production and utilization rates by various products; and in forest land ownership.
Ecoregions defined by common climatic and vegetation characteristics, shown as domains, divisions, provinces and sections.
Extensive data on the animals of the United States, Canada, and the Western Hemisphere
Use this page to search the USGS Archives for habitat reports and research papers
Hydrologic / Water Resources Data
NHDPlus is an integrated suite of application-ready geospatial data sets that incorporate many of the best features of the National Hydrography Dataset (NHD), the National Elevation Dataset (NED), the National Land Cover Dataset (NLCD), and the Watershed Boundary Dataset (WBD).
Access to free online scientific information about oceans, coasts, and coastal watersheds.
Land Cover and Land Use Data
Produced by the State of California. This program uses Landsat Thematic Mapper (TM) satellite imagery to map land cover types and derive land cover changes across all ownerships. The state is covered in five unique project areas. One project area is completed each year, then revisited and updated every fifth year.
Nineteen land cover classes defined using the Land Cover Classification System (LCCS) standard developed by the Food and Agriculture Organization (FAO) of United Nations. From the Council on Environmental Cooperation (CEC) North American Environmental Atlas 
The GlobCover Portal provides access to the results of the GlobCover project: Global-scale composite and land cover maps produced using the 300m MERIS sensor carried aboard the ENVISAT satellite.
Global-scale collection of links to agriculture-related land cover and terrain data bases. Includes data for remote countries.
Collaborative effort by NASA and University of Maryland. Provider of comprehensive earth science data and derived data products
HYDE presents (gridded) time series of population and land use for the last 12,000 years ! It also presents various other indicators such as GDP, value added, livestock, agricultural areas and yields, private consumption, greenhouse gas emissions and industrial production data, but only for the last century.
The LCI addresses landcover topics at local to global spatial scales, worldwide. Well-stocked data portal for local, national, and global landcover data. Includes the National Land Cover Dataset.
Global land cover classification using a classification tree approach
Map and Digital Terrain Data
High quality elevation data for large portions of the tropics and other areas of the developing world.
The latest and most complete version of the CGIAR SRTM 90 meter resolution data set.
Two Data Portals: ASTER GDEM  1 Arc Second Digital Terrain Data
Best for obtaining fewer than 100 ASTER GDEM 1 degree**2 data tiles
Best for bulk download - more than 100 - data tiles
The DCW is a comprehensive 1:1,000,000 scale vector basemap of the world, designed to meet the needs of pilots and air crews in medium-and low-altitude en route navigation and to support military operational planning, intelligence briefings, and other needs.
A good place to obtain SRTM global-scale digital terrain model data sets in three different spatial resolutions (cell sizes): 30 meter/90 meter/1 kilometer.
A Global terrain slope and aspect database compiled from Shuttle Radar Topography Mission (SRTM) elevation data.
A clear explanation of Latitude / Longitude calculation on the Earth surface grid.
Comprehensive clearinghouse for digital terrain and land cover data,
Including informative articles.
EROS Data Center portal for worldwide digital Earth terrain data.
Vector dataset containing boundaries for all world countries.
The goal of VTP is to foster the creation of tools for easily constructing any part of the real world in interactive, 3D digital form. Terrain data sources and discussions of terrain simulation methodologies.
Remote Sensing Satellite Data
The United States Government maintains these 'scientist-friendly', interactive Web portals for searching for and acquiring (mostly) FREE geospatial datasets:
University of Maryland maintains this portal for the complete, worldwide Active Fire detection of actual fires) and Burned Area (areas affected bu fire) Products imagery products derived from MODIS Sensor data.
Search and order earth science data from various NASA and affiliated centers: Atmosphere/Cryosphere/Land/Ocean/Solar domains. Account required for downloads.
MODIS AQUA and SeaWiFS Ocean-Monitoring satellite data and software tools
Provides access to a diverse data collection of including aerial photography, vector map data, digital elevation maps, landcover, and carbon mapping imagery. Designed for downloads of individual data product files
Home Page / Data Portal for the primary archive and data management center for remote sensing data collected by the United States Goverment.
Gives access to several online search/order tools for remote sensing data, including: Landsat, MODIS, ASTER, other imagery. Supports download of multiple images/data sets. Account required for downloads.
TerraLook portal permits users to create their own collections of georeferenced JPEG satellite images from ASTER and Landsat sensors. Good for scientists wishing to learn about remote sensing data.
A collaborative, comprehensive Harmonized World Soil Database compiled from regional and national updates of soil information.
As a World Data Centre for Soils: serves the scientific community as custodian of world soil information by collecting, scrutinising, analysing and disseminating data and information, and making them freely available.
A compendium of online soil survey information, including soil geographic databases.