A Guide to the Library of Congress’s Collection of Fire Insurance Maps

Fire insurance maps are an invaluable tool for history research: they give a detailed snapshot of a city’s built environment at a given point in time. And they were made for just about every city, town and village. The Library of Congress has 50,000 fire insurance maps (700,000 individual sheets) in its collection, most of which were produced by the Sanborn Map Company. The Library has just released a resource guide to help researchers navigate its collection, and explain which maps are available (copyright is an issue with more recent maps). Announcement here.

Previously: Fire Insurance Maps Online.

U.S. COVID Vaccination Rates and Active Cases

Screenshot of an interactive bivariate choropleth map showing COVID vaccination rates and active cases in the United States.
McKinsey & Company (screenshot)

This interactive map compares U.S. COVID vaccination rates with active cases at the county level. Created by McKinsey and Company’s COVID Response Center, it’s a bivariate choropleth map that shows two variables at once. (If this confuses you, the legend helps.) It’s a good way to see where low vaccination rates correlate with lots of COVID cases (red on this map), or high vaccination rates with few cases (teal); the map lets you explore other variables as well. [Maps Mania]

Mapping Broadband Access (or Lack Thereof) in America

Map showing U.S. counties where less than 15% of U.S. households access the internet at broadband speed
The Verge

The Verge maps the gaps in U.S. broadband coverage. “This map shows where the broadband problem is worst—the areas where the difficulty of reliably connecting to the internet has gotten bad enough to become a drag on everyday life. Specifically, the colored-in areas show US counties where less than 15 percent of households are using the internet at broadband speed, defined as 25Mbps download speed. (That’s already a pretty low threshold for calling something ‘high-speed internet,’ but since it’s the Federal Communications Commission’s standard, we’ll stick with it.)” They’re using anonymized Microsoft cloud data rather than the FCC’s numbers (which don’t have a good track record reflecting real-world speeds).

Previously: The FCC’s Broadband Map ‘Hallucinates’ Broadband Access.

Historical Landslides in Canada

Map: Historical landslides that have resulted in fatalities in Canada (1771-2019)
Excerpt from Andrée Blais-Stevens, “Historical landslides that have resulted in fatalities in Canada (1771-2019),” Geological Survey of Canada, 2020.

The third edition of a map showing landslides that have caused fatalities in Canada since 1771, created over six years by Geological Survey of Canada research scientist Andrée Blais-Stevens, was recently released. The Ottawa Citizen has the story; the map in question can be downloaded in PDF format here (48.7 MB).

Atlas du réseau ferré en France

Atlas du réseau ferré en France (cover)The French state railway company SNCF has a lot of nice maps of their rail network, some of which I’ve posted here before; of particular interest, though, is the Atlas du réseau ferré en France, which gathers them into an 86-page booklet, and includes a lot of diagrams showing, for example, passenger and freight volumes. It’s available here as a flipbook and can be downloaded as a PDF if you give them your email; I’d be over the moon if it existed as a hard copy.

Another Maps Issue from Library of Congress Magazine

Library of Congress Magazine (cover)The May-June 2021 issue of Library of Congress Magazine is entirely given over to maps: a lot of short one-page features on all sorts of subjects from Ortelius to COVID. Direct link to the PDF file (6 MB). [Edney]

This isn’t the first time the magazine has done this: the September-October 2016 issue (2.9 MB) was also almost entirely dedicated to maps. Previously: Library of Congress Magazine’s Map Issue.

Mapping The Freedom Race

From Lucinda Roy, The Freedom Race (2021).

For her upcoming fantasy novel The Freedom Race (Tor, July 2021), Lucinda Roy decided to do what a lot of fantasy authors do: draw a map. But she did it in a way that most fantasy authors don’t: “I needed a persona map—a map that could feasibly have been drawn by Ji-ji, the main character in the book. Her map doesn’t simply introduce the world to readers, it actually appears inside the narrative and helps catalyze the action.” Then she decided that she needed two maps, both intrinsic parts of the story, both revealing a great deal about their respective mapmakers. Very much relevant to my interests: I wrote, after all, a piece about fantasy maps in fantasy worlds (and got some flack for it). Though it’s the first time I’ve heard the term persona map. A new term of art?

Mapping Shallow Seafloors with Satellite Data

Seafloor map of Bermuda
David Lagomasino/East Carolina University

NASA Earth Observatory summarizes recent work in using satellite data to improve our maps of shallow seafloors—where the situation changes more often than traditional sonar methods can track—by, among other things, using a laser altimeter system on one of NASA’s satellites.

In 2021, Nathan Thomas and Lola Fatoyinbo of NASA’s Goddard Space Flight Center, along with colleagues from three countries, took another step by mating ICESat-2 measurements with images from Copernicus Sentinel-2 to derive bathymetry at better resolution. The team mapped the shallows down a depth of 26 meters (85 feet) around Biscayne Bay in Florida, the Gulf of Chania in Crete, and the island of Bermuda.

Thomas and colleagues compared their satellite-derived bathymetry with maps made from traditional topographic surveys, multibeam sonar, and nautical soundings. Their new maps had a resolution of 10 meters, improving upon the current 115-meter resolution dataset for Crete and the 30- to 90-meter datasets for Florida and Bermuda. The existing data for Florida and Bermuda are composites of lots of sources spanning 63 years, while the ICESat-2/Sentinel-2 maps offer a contemporary assessment of underwater structure.

See also this earlier Earth Observatory item from last year. (Deep water bathymetry is another thing: light can’t get down that far. But out-of-date soundings are less impactful on shipping.)

The Unicorn of Map Projections

It’s a shame that Sarah Battersby’s essay in The International Journal of Cartography, “The Unicorn of Map Projections,” is behind a paywall: it looks at the recent rash of map projections that purport to solve all our mapping problems.” There have been more than a few that have claimed the title of “most accurate map”; Battersby refers to these projections as a class as unicorns. The most recent example of this I dismissed as the cartographic equivalent of a spherical cow; five years ago there was also Narukawa’s AuthaGraph map; and of course there was the Peters map.

About 500 of you subscribe to The Map Room via its email digest. That feature is powered by FeedBurner. Last week FeedBurner announced that it’s being moved to new infrastructure. Several features will as a result be discontinued—including email subscriptions. I’ve been investigating possible alternatives. The one that looms largest is Mailchimp; its free plan maxes out at 2,000 subscribers, which is four times what we need right now, so there’d be room to grow—but that limit is a hard limit (Mailchimp’s paid plans are way too expensive given this little website’s income). In any event I’ve got some time—until July, I think—to come up with a solution. Will keep you posted.

A Network Map of Ottawa’s Cycling Network

Hans on the Bike map of the Ottawa-Gatineau cycling network
Hans on the Bike

Hans on the Bike has produced a map of the Ottawa-Gatineau bicycle path network in the style of a Beck-style subway network map. “Is a metro map for cycling useful? I think it has a function in visualizing a network in an easy and pleasing way,” he writes. “In the end it is more a fun project than a bike map avant la lettre.”

Nothing wrong with it as a fun exercise, but can it actually be used? As someone who back in the day biked quite a lot of the Ottawa and Gatineau bike trail network, I can’t use this map. I don’t recognize the path network. Part of it is because many of those paths have names that he doesn’t use; part of it is the conceit of creating “stations”; part of it is that a surface path network that can be entered or exited at any point is not well served by a network diagram. It makes sense to abstract a subway network from the street level, because you’re basically travelling from station to station. You’re not doing that on a bike; you’re in the neighbourhood.

Mapping Vaccine Hesitancy in the United States

The Centers for Disease Control and Prevention released data and maps showing the estimated rate of COVID-19 vaccine hesitancy in the U.S. on a county-by-county basis. The data is based on a question in the Census Bureau’s Household Pulse Survey that asked respondents whether they’d get a vaccine for COVID-19 once it was available to them. Methodology and datasets here. [Boston.com]

French Rail Services as Network Diagram

Jug Cerovic

Metropolitan France—mainland France without Corsica and its overseas territories—is often referred to colloquially as l’Hexagone. Jug Cerovic, whose work we are familiar with here, has taken that metaphor and run with it with this network diagram of France’s main passenger train lines: the grid is hexagonal, and it works. Lines are colour-coded: TGV lines are blue if they start in Paris and red if they route around it or connect regions directly (a relatively new development; intercity lines are blue-grey, regional lines are orange, and night trains are grey. International routes are also included. It’s actually quite easy to see what cities and towns get what kind of train service, and what services exist between two points—exactly what a network map should do.