From: Current practices in spatial analysis of cancer data: data characteristics and data sources for geographic studies of cancer
Dataset name
Source Agency
URL
Geographic Resolution
Digital orthophoto quadrangles
USGS
http://edc.usgs.gov/products/aerial.html
1:12,000
Satellite imagery
http://edc.usgs.gov/products/satellite.html
1 meter to 1 km
National Landcover Dataset (NLCD) 1992
http://edc.usgs.gov/products/landcover.html
30 meters
Multi-resolution Land Characteristics (MRLC) 2000