Image overlays have consistently been one of the neatest features in Google Earth. The most common use of overlays is to show imagery that is more fresh than what can be found in Google Earth (such as this one from President Obama’s Inauguration or this one from the oil spill in the Gulf of Mexico). However, overlays can also be used to showcase alternate maps such as detailed topography or historical maps like we’ll show you today.
The North Carolina Maps collection features an impressive collection of online maps from various sources, many of which can be viewed in your browser or downloaded to view directly in Google Earth.
By visiting their Historic Overlay Maps page you can find dozens of maps that can be loaded into Google Earth.
Selected maps from the North Carolina Maps project can be viewed as Historic Overlay Maps, layered directly on top of current road maps or satellite images. By fading or “seeing through” the historic maps, users are able to compare the similarities and differences between old and new maps, and to study the changes in North Carolina over time.
The Historic Overlay Maps are presented with a historic map placed on top of a current Google street map. The historic map has been geo-referenced, meaning that it should line up very closely with the current map.
Check out their Historic Overlay Maps to try them for yourself.
(via Google Maps Mania)