The ten images of San Francisco above show growth of the city from 1853 to 2015. This display demonstrates how maps of varying sizes and scales can be georeferenced and then easily compared, all occupying the same coordinate space. Geographical Information System applications, known as GIS, make it possible to compare and contrast maps side-by-side, or to superimpose them in translucent layers at the same scale. Aside from visualizing changes in the landscape from the different maps, GIS has many other powerful tools such as spatial and statistical analysis, optimization of routes and viewing areas called view-sheds for urban planning purposes. Modern day GIS has its origins in the 1960s and has revolutionized the world of maps.
The source maps for the images above were georeferenced and placed in Google Earth. Red outlines on the reproductions arrayed on the floor of the case show the sources of the comparison areas.
You can view the 1859 US Coast Survey map of San Francisco in the Rumsey georeferencer here.