As part of a series exploring the history of National Park Service visitor guides, photographer QT Luong takes a closer look at the vistor guide maps—specifically, the maps for Yellowstone National Park, which he tracks through multiple iterations. “Given the importance of the park, Yellowstone maps have been subject to more revisions than any other park maps, which makes it possible to tell a more complete story. This also means that the history of maps from other parks is far from strictly paralleling the evolution of the Yellowstone maps. However, by examining my extensive collection of park maps, I can confirm that it follows the same general outline.”

To mark the 70th anniversary of the legislation creating the United Kingdom’s national parks, the Ordnance Survey has released the above poster showing each of Britain’s 15 national parks in relief. The 84 × 119 cm poster can be had for £15 via the Ordnance Survey’s shop.

As U.S. government publications, national park maps are in the public domain. Since 2013, park ranger Matt Holly has been uploading them to the unofficial National Park Maps site, which now has more than a thousand maps available for download as high-resoluation images or PDFs. [CityLab]