New, publicly downloadable GIS data sets are rapidly becoming available for socioeconomic, geological, ecological, and many other areas of land and “human geography” analysis. Below is a list of national GIS data relevant to park planning and public land use:
Open Street Map: Crowd-sourced data for the whole world, consisting of most things you'd find on a standard local paper map: points of interest, buildings, roads and road names, ferry routes etc.
U.S. Cartographic Boundaries: Cartographic boundaries, including city boundaries, counties, school districts, voting districts, zip code areas and congressional districts. Mainly from the 2000 census, but some later data.
USGS Land Cover Institute: Links to almost all land cover data sets.
Protected Areas Database of the U.S.: Shapefile of all protected areas in the US including attribute data description uses, reasons for protection, and legal status.
Geological Maps of the U.S. States: Detailed geological maps with extended attribute data for each state.
TIGER: U.S. Census data.
TIGER Line 2010: 2010 extracts from the census database. These files contain the boundaries of census areas, which can then be linked to census data tables.
National Historical GIS: Census-extracted historical data between 1790 and 2010.