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.

On the Library of Congress’s map blog, World’s Revealed, Julie Stoner takes a look at a rather unusual example of a bird’s-eye (or panoramic) city map. “The Geography and Map Division has over 1,700 of these beautiful panoramic maps in the collection, but one item stands out above all the others as one of the crowning achievements of the art, Camille N. Dry’s 1875 atlas, Pictorial St. Louis; The Great Metropolis of the Mississippi Valley. A visually stunning atlas, instead of only one sheet, it was produced on 110 plates, which if trimmed and assembled creates a panorama of the city measuring about 9 by 24 feet.”

At Worlds Revealed, the Library of Congress’s map blog, Tim St. Onge looks at, and provides the background on, a series of six maps prepared by Frederick E. Pierce for a report on living conditions in New York’s tenement housing in 1895, including a stunningly bizarre map of ethnic groups living in the city.

Pierce’s map of nationalities, however, is a more memorable, if confounding, centerpiece. Aiming to convey diversity among immigrant communities in New York, the map depicts the proportion of major “nationalities” in each sanitary district of the city. The result is a dizzying array of zigzag stripes and scattered points. As Pierce writes in his explanatory notes accompanying the Harper’s Weekly publication, the original map was produced in color and adapted to black and white for publication, but the reproduction “is almost as effective and quite as illustrative as the original.” Despite Pierce’s confidence, perhaps the average reader could be forgiven if they find the map to be more difficult to parse. In fact, the map seems to resemble more closely the dazzle camouflage, a design aimed at confusing the observer, used on British and American warships in the first half of the twentieth century.