U.S.G.S Topographic Maps: (DRG) GEOTIFF Images and Other Data
Access to map data has improved in recent years. Below are some preliminary steps that may help guide your search for scans of topographic maps in the United States, or a wide assortment of digital map data:
- If you don't know the quadrangle maps you need click on this link to MapMart. Make sure you are in the U.S.G.S Digital Raster Graphics section. Choose 1:24,000 is selected and click on the Begin Search button to the right. You will be presented with a zoomable map of the United States. Click on a state and proceed to Zoom In until you find the names of the quadrangles you want.
- Click on this link to go to the USGS Geospatial Clearinghouse. It is worth taking the time to explore this site that archives abundant map data useful to geologists. For example, once you browse to the correct place, Topographic Maps are arranged by a seven digit code related to latitude and longitude. Scroll down the list until you find the map you are seeking; Click on the pertinent file folder and you be taken to another page that offers various color image, DOQ and DRG downloads for that quad. Use a Save Target As on the file (.tif) to download the quadrangle.