
The original historical maps are first made into digital images by scanning them with high resolution digital cameras. Cultural features on the maps can be compared to the modern satellite views using the slider bars to adjust transparency. Some of the maps fit perfectly in their modern spaces, while others (generally earlier period maps) reveal interesting geographical misconceptions of their time and therefore have to be more distorted to fit properly in Google Maps and Earth. Each map has been georeferenced, thus creating unique digital map images that allow the old maps to appear in their correct places on the modern globe.

These maps can also be seen in the Gallery layer of Google Earth, Rumsey Historical Maps layer.Īll the maps contain rich information about the past and represent a sampling of time periods (1680 to 1930), scales, and cartographic art, resulting in visual history stories that only old maps can tell. The over 120 historical maps in the Google Maps and Google Earth Rumsey Historical Maps sites have been selected by David Rumsey from his collection of more than 150,000 historical maps in addition, there are a few maps from collections with which he collaborates.
