www.topozone.com

EPA Watershed Information Network (WIN)

USGS Maps

• a source of USGS maps

MapQuest

• a good general road mapping program.

PA DEP Geographic Information Systems

• this is the starting page for the eFACTS-Spatial, a Geographical Information System (GIS). In real words, this is a mapping program that lists DEP regulated sites, including information on ownership – a great tool for Step 3 – Inventory of Potential Contaminant sites

terraserver

• Microsoft, working with everyone from the U. S. Geological Survey to the Russians, has a site that contains aerial photographs of over 50% of Pennsylvania. Many are free for download. Can you find your wells or intake?

Pennsylvania Spatial Data Access - The Pennsylvania Geospatial Data Clearinghouse

• this site has a multitude of data layers for GIS and for general mapping purposes…everything from topographic quadrangles to oil & gas well locations to state park locations. All free for downloading…watch out for the Digital Ortho Quarter Quads (DOQQs), though, … 40 Mb over a phone line can take forever…

EPA Envirofacts - Data Warehouse and Applications

• EPA’s GIS system. A single point of access for 8 difference EPA databases of regulated facilities. You can create maps on many different levels such latitude & longitude, county level, watershed, etc.

Pennsylvania Topographic & Geologic Survey - Department of Conservation & Natural Resources

• PA’s own Geologic Survey page. If you’re into fossil hunting, you can download (free) an out of print book on the best roadside locations in PA. They also have the geologic maps for the whole state along with a list of all their publications and more –

US Geological Survey

• US Geological Survey site for maps, including aerial photos and topo maps.