mapsnap

mapsnap georeferences the Library of Congress's Sanborn fire insurance maps automatically. It reads the street names printed on each sheet, matches them to OpenStreetMap, and places the sheet on today's map. The results are IIIF georeference annotations for tens of thousands of volumes, free to download and reuse.

• See an example: Brooklyn, 1939, vol. 263 sheets over today's map, in the Allmaps viewer.
• Download the data: run v1.329,673 volumes and 341,093 sheets placed, by state or all at once.
• Read how it worksThe blog post introducing mapsnap.
• Get the codemapsnap on GitHub.