IT JUST GOT way, way easier to search and browse the US Geological Survey’s collection of historical topographic maps, thanks to a new online map viewer. These maps—more than 178,000 of them—date back to 1880, and they cover the entire country. Best of all, they’re free to download for anyone who wants to, say, check out the contours of the Grand Canyon or study the urbanization of the San Francisco Bay Area (see below).
Hunting for historical topo maps on the USGS site used to be confusing and annoying. It involved a lot of clicking on what you hoped was the right thing, squinting at the tiny preview maps, and twiddling your thumbs while the enormous full-sized version downloaded. And then starting over when it turned out to be the wrong thing.
It was even frustrating for USGS employees who needed to access the maps for their work, says Chris Garrity, a geographic information scientist at USGS. Garrity was one of those people, and a few years ago he decided to do something about it.
He first spent some time analyzing traffic to the old site to get a better handle on how people were using it. “We basically had two sets of users,” he said. “People just looking for maps of their home town, and people who knew exactly what they wanted—this place, at this time, at this scale.” He designed the new viewer to make life easier for both groups.
Now, browsing and searching for maps is much more intuitive. You can type or zoom in on a particular place, limit your search to maps of a particular scale or from a particular range of dates. You can download them in a variety of formats, from JPGs (fine for printing out a nice map to put on your wall), to KMZ files (to import into Google Earth), to GeoTIFFs (for the power users who wants to import maps into GIS software). There’s even a YouTube tutorial that teaches you some handy tricks (pro tip: hold the shift key and drag the mouse to highlight an area to zoom in on).
Garrity hopes to create a similar interface for the agency’s stash of geologic maps by the end of the year and to eventually include the most up-to-date topo maps. For now you can download files or buy prints of those newer topos from the USGS online store using the old interface. Be patient.