I downloaded a shapefile of North American topographical contours a while ago, and never spent much time with it until recently, when I noticed there are some really fascinating subsets of the United States.
For reference, the file comes from this page, and contains contours at 100-meter resolution. That’s actually not very detailed if you’re looking at a county or a city, but for an area this large with a pretty wide range in elevation, it’s plenty to get the big idea.
Speaking of big idea, here’s the full layer, with the color scale ranging from blue at the low end to red at the highest elevations:
Okay, big deal – flat in the east and south, mountains in the west, right? Stay with me…
First, a footnote: all of the following subsets use the same color scale as the full-scale image above, so elevations are comparable across images, but each is zoomed to different levels to show more detailed features.
I’ve also intentionally made state boundaries very faint and not added any text to locate cities or bodies of water – I want these maps to focus on topography.
Let’s start with one of the most eye-catching examples: the California central valley.
Let’s not start any arguments about water rights and the future of pumping groundwater to feed almond trees, but it is nonetheless impressive to think about the agricultural output of this area.
Another thing I noticed is that this map pretty closely resembles a map of the San Francisco Bay area, which itself is only a subset in the mid-upper-left of the image. It’s always cool when fractal-type patterns emerge in real life.
Sticking to California (and valleys), let’s look at the lowest-elevation area in North America: Death Valley.
There’s another well-known valley not too far away: the Grand Canyon.
The contrast between Death Valley and the Grand Canyon is interesting – Death Valley is broad and extremely flat in the midst of a lot of elevation change (look around it), while the Grand Canyon is steep and narrow, surrounded by relatively flat land.
On the topic of elevation change, one state catches more jokes than it deserves about being extremely flat: Kansas.
Actually, we need to set the record straight: Kansas might be the most planar state, but that plane is not at a constant altitude. Actually, if you took the lowest and highest point in each state and calculated the difference, do you know where Kansas would rank?
21st!
That’s right: Kansas has over 3300 feet of elevation change from east to west, and 20 states have less than that, among them states with actual mountains like Pennsylvania and New Jersey.
And honestly, everyone’s iconic mountain state, Colorado, is half-Kansas, when you look at its topography:
You want to talk about flat? Let’s take a look at sad, flat, Florida (not the best tourism slogan):
If we move up the Gulf Coast to the west, there’s a similarly flat area (but with more interesting surroundings), in the Mississippi Delta. I would not have guessed that both Mississippi and Alabama reach 100-meter elevation within a short drive from the coast, while Louisiana remains under 100 meters for quite a distance.
Back to mountains: as you move back to the northeast, the first major elevation change comes at the Great Smoky and Blue Ridge Mountains, both southern Appalachian subranges.
If you follow those mountains northeast, you get to an interesting formation from West Virginia through central Pennsylvania:
Note how quickly those jagged and tight topographic lines fall into completely flat plains in Maryland’s eastern shore, Delaware, and southern New Jersey (remember, flatter than Kansas).
The far northeastern United States also have mountains (assuming you aren’t comparing to the Rockies). This is the Adirondacks in northeastern New York, merging into the Green Mountains in Vermont, and the White Mountains in New Hampshire:
We’ve been on the east coast for too long now, where the topographical lines don’t go beyond green. Let’s head back west and look at some real mountains, for instance, the Yellowstone and Grand Teton ranges of Wyoming:
I keep noticing that mountain ranges often don’t occupy a huge surface area footprint, at least compared to how much they dominate the landscape in a photograph. Looking at a range from below, you’d think they extend farther than they appear to in these images.
Nevada and Utah don’t get as much credit as they should for being in the high-elevation club. Nevada’s ranges look almost like sandbars, while Utah has two relatively tall ranges, of course with a basin cut out for the Great Salt Lake.
Let’s finish up in the Pacific northwest, with a view of Puget Sound, the Olympic Peninsula, and if you look closely, Mount Rainier rises in the south, and Glacier Peak in the northeast.
