Help the AGSL Georeference our maps!
When we scan a map into our digital collections, the computer doesn’t know where the map is, only how to display the image as pixels of various colors. The process of telling the computer what the map is showing is called georeferencing. This is done by comparing the scanned map side-by-side with a map that has a known location and selecting points that the two maps share–control points.
See the tutorial here.