What Is Geospatial Data?
- Definition of “Geospatial” by Dictionary.com–“
- Definition of “Geospatial data” by US. EPA.–“Data contains information that identifies the geographic location and characteristics of natural or constructed features and boundaries on the earth, typically represented by points, lines, polygons, and/or complex geographic features. This includes original and interpreted geospatial data, such as those derived through remote sensing including, but not limited to, images and raster data sets, aerial photographs, and other forms of geospatial data or data sets in both digitized and non-digitized forms.” 
Where to Find/download Free Geospatial/GIS Data for Locations in the United States?
It seems to be a “sweet dream” if all Geospatial/GIS data could be found and downloaded freely in one single website. Unfortunately, life is hard, and sometimes the dream never come true.
Thus, it becomes essential know where to search for the Geospatial data and also understand what data types and information are included. Here is a list of free, downloadable, highly reputable, Geospatial/ GIS data sources for U.S. regions:
- Features: GDG is the One Stop Source for environmental and resources data, which allows users to explore, browse, select data based on customized needs, particularly obtained by states, by counties, by place, by Latitude/ Longitude, and even by custom Area of Interest (AOI) with the interactive map. Selected data can be downloaded (free) or shipped on CD or DVD (may cost money).
- Data Contents: Environmental and natural resources data, such as climate PrismRaster, Census block data, elevation, hydro-geographic map, land cover, land use, soil survey, transportation routes, topographic image, etc.
- Data Formats: Raster and remote sensing imagery –provided in their native format; vector layers–ESRI Shape or ESRI File GeoDataBase.
- Features: The download platform allows to view and download the most current topographic data from the USGS and other federal, state, and local partners freely.The National Map viewer allows visualization and identification queries (but not downloads) of other featured data, such as Ecosystems, Protected Areas, Gap Analysis Program Land Cover, Wetlands, National Park Service Boundaries, etc.
- Data Contents: Provide data from 8 primary data themes — Elevation, Orthoimagery, Land cover, Hydrography, Geographic Names, Boundaries, Transportation, Structures, while maps include: US Topo and Historical Topo.
- Data Types: wide variety of vector and raster data.
- Features: USGS EarthExplore provide access not only to one of largest databases of satellite and aerial imagery but also to remote sensing data worldwide. Users can query data by enter an address or place name, coordinates or click the map to define your search area, and/or choose a date range.
- Data Contents: Provide satellite imagery data, aerial photography, elevation and land cover datasets, digitized maps, and USGS Image Gallery collections.
- Date Types: Remote sensing data–e.g., DOQ, AVHRR, LiDAR, etc.
- Features: It applies remote sensing technology to track seasonal changes in vegetation on regional, continental, and global scales.
- Data Contents: Provide historical remote sensing phenology (RSP) image data and graphics across U.S. are made freely available from the USGS/EROS Center through this website.
- Data Types: CONUS 1-km AVHRR RSP, Eastern CONUS 250-m eMODIS RSP, and Western CONUS 250-m eMODIS RSP.
- Features: GAP is an element of the U.S. Geological Survey and help implement the Department of Interior’s goals of inventory, monitoring, research, and information transfer. This program provides conservation information to the public, so that informed resource management decisions can be made; also facilitate the application of GAP data and analysis to specific resource management activities.
- Data Contents : 4 primary data sets: land cover, protected areas, species and aquatic.
- Data Types: Wide variety of vector and some raster data.
- Features: Natural Earth provides a public domain map dataset available at 1:10m, 1:50 m, and 1:110 million scales, featuring tightly integrated vector and raster data. The best part is that the data is in public domain, which means users have the right to disseminate and modify the data in any matter.
- Data Contents: Cultural vectors (e.g., counties, states, urban areas, land use, etc.), Physical vectors (e.g., coastline, land, rivers and lake centerlines,etc.), and Raster basemap data.
- Data Types: Natural Earth Vector comes in ESRI shapefile format. Natural Earth Raster comes in TIFF format with a TFW world file.
- Features: Open Topography facilitates community access to high-resolution, Earth science-oriented, topography data (LiDAR), and related tools and resources, supported by the National Science Foundation (NSF).
- Data Contents and Types: LiDAR point cloud and processing data (90% United States, Canada, Australia, Brazil, Haiti, Mexico and Puerto Rico)
8. Don’t forget “State-level” or “Local” data sources:
While download platforms above provide geospatial data across U.S., many state or local governments also provide useful data sources in the regional scale.
 Dictionary.com’s 21st Century Lexicon Copyright © 2003-2010 Dictionary.com, LLC http://dictionary.reference.com/browse/geospatial
 U.S. EPA’s National Geospatial Data Policy, August 2005