An additional feature of East of the Cascades is the availability of map resources for pages on which a compass icon is part of the locator map as illustrated at right. Clicking on the locator map will bring up a 3-D globe on which a historic map is overlayed. These overlays are roughly contemporary to the excerpts on each page and lend geographic context to each selection. While an attempt has been made to accurately fit each map to the underlying globe the registration is not perfect. The inland west was largely unknown to map makers in the first half of the nineteenth century due to limited exploration. As knowledge of the continent improved so did the accuracy of available maps.
To use this feature you will need to make sure that a Google Earth plug-in is available to your internet browser. The plugin may be downloaded at: Google Earth Plug-in.
The map overlays are large files. Please be patient as they load.