Speaking of georeferencing old maps, the Leventhal Map Center at Boston Public Library has a collection of late 19th- and early 20th-century urban atlases. Their Atlascope platform presents 101 of them in a web interface overlaid on a modern street map. The Leventhal is now looking to expand Atlascope’s coverage beyond the Boston area to towns and counties across Massachusetts, and is raising funds to do so (it can apparently take 60 hours to process one atlas). Details on sponsoring an atlas here. See their Instagram post.

The blog of the Library of Congress’s Geography and Maps Division isn’t the first place you’d expect an explanation of the GeoTIFF format (basically, an image file in TIFF format that includes georeferencing metadata, so that the image can be projected on a map grid). But georeferencing old maps so that they can be placed on a modern map grid is definitely a thing, and Carissa Pastuch’s piece, “The Secret Life of GeoTIFFs,” looks at GeoTIFFs through the lens of an experimental dataset of georeferenced late 19th- and early 20th-century Austro-Hungarian maps.