I’m working on a project that references USGS topographical maps (topo maps). I’ve found a Google Earth, KML (Keyhole Markup Language) file that allows downloading free USGS 7.5 minute topo maps by simply clicking on an area of interest from within Google Earth.
The free KML is can be downloaded from Digital Data Services. It downloads as a KMZ (KML Zipped) file. After downloading, just double click the file and it loads into Google Earth. It doesn’t matter if Google Earth is already running. This adds the USGS Topo Index to your Temporary Places in the Places side-bar.
Next, you’ll need to activate it by clicking the radio-button, in the Places side-bar, that activates the state you’re interested in. This overlays your Google Earth view with the USGS Quadrangle system. You’ll need to navigate to the Quad you want by click and drag and zoom. When you click within a Quad, you’re presented with a window for downloading the desired map as a tiff file. Here’s a portion of what you’ll see.
When you quit Google Earth, you’ll be asked if you want to save the USGS Topo Index. If you do, it’ll be there the next time you launch Google Earth.
Printing Large Images
Now that you’ve downloaded a Quad map, printing becomes a issue. Printing from an application like Preview is useless. The entire map is restricted to fit on a single sheet of paper. For most of us, that means 8.5 x 11 inches. The solution is PosteRazor. It cuts a raster image (jpeg, tiff, etc) into pieces that can be printed and later assembled into a poster. Here’s an idea of how it works: