A Sanborn Map For Every New Tab

I’ve spent an inordinate amount of time stitching Sanborn maps into town-wide tifs, georeferencing them, and then creating map tiles to view on the web. The results often vary depending on DPI of the scanned maps, the software I use to stitch, and the quality of my georeferencing, but it’s always fun to to try and understand the geography of these early settlements.

This process also allows one to pan and zoom over the map, which often leads to interesting discoveries outside the larger dominant industries– a fish market in a small corner store, or the city stable for the fire department’s horses. Here are a few of my favorite examples:


The Swanton Suspender company, 1882


Kow-Kure, the predecessor to Bag Balm, in Lyndonville in 1900

But how to browse all through all the available maps without taking the time to stitch and georeference each one? When my Earth View new tab extension broke a few weeks ago, I decided to create one of my own for Vermont Sanborn Maps.

As always, the hard part was getting the data. The Library of Congress has a few different APIs for serving this data, so I wrote some python to code read the source page, then check each city for the years available, then download each sheet.

I uploaded this images to an S3 bucket (s3://vermont-sanborn-maps), where they would be easily accessible. I found a few tutorials about creating chrome extensions, and with 50 lines of JavaScript and HTML, I put together a simple viewer to load a random Sanborn map every time a new tab is opened.

All the code is on GitHub here, and the extension from the Chrome Store here:
https://chrome.google.com/webstore/detail/vermont-sanborn-maps-new/mdigfmpeaidjibmfjhadcnbioejfclji.

Let me know if you find anything interesting!

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