I have had many requests over the years to add a USGS topographic Map overlay without the map borders. This is a huge project and I have finally decided to move forward with it.
These maps will be made available in downloadable bundles. Each Topographic Map Mosaic bundle typically contains 64 7.5-minute series (1:24,000 scale) USGS topographic maps and covers a 1×1 degree area of the United States (about 3,000 to 4,000 square miles). An installation program is included that will automatically add the maps to Google Earth on your PC (so long as Google Earth is already installed). Mac users should be able to install the maps using the unzip command in the Terminal application (“unzip N46W123-Setup.exe” for example). There is also a Mac program call The Unarchiver that might allow you to run the EXE file directly, but I do not have the ability to test it out. If anyone has any other Mac tips, please post a comment.
The maps have been created using Google Earth Super Overlays, which means the maps will automatically increase in resolution as you zoom in. You can purchase multiple map bundles and they will join together seamlessly in Google Earth. The maps are georeferenced so they align with the underlying imagery in Google Earth. In addition, the 10-meter National Elevation Dataset (NED) has been used to apply hill shading to the maps to enhance the topography.
The map bundles range in size from 100 to 600 megabytes, and are priced at $5.00 per bundle, which works out to less than 10 cents per map. Some of the coastal areas are priced at $1.00 if there are only a few maps in the coverage area. This method of delivery allows the maps to be used off-line and also allows the maps to be viewed much faster, and in higher resolutions than would be possible streaming the maps over the internet. You also don’t have to worry about connectivity issues, slow servers, etc.
The first release covers the western United States (West of Longitude -113) and I intend to release map bundles covering the rest of the United States in the coming months. I have two PCs working 24/7 creating the maps.
More information about how to order and download the maps can be found on this web page.
A sample map bundle (214 megabytes) covering the area north of San Francisco is available if you want to try one out for free. In addition, I have made a second map bundle covering the Mt. St. Helens area of Washington (555 megabytes) available for free for the month of December.