Die flachsten US-Bundesstaaten im Ranking (Widerlegung der zuvor veröffentlichten Karte von Dobson/Campbell 2014)

The 2014 Dobson/Campbell map seemed like it was going out of the way to label Kansas as ’not flat‘, and noticing both authors were from the University of Kansas, I decided to do some flatness checks on my own. I didn’t replicate their ‚ray tracing‘ method identically, as a least squares difference is a much more intuitive measurement for flatness to me, but I wanted to look at their ‚windows‘ that they chose for their measurement.

They basically scan 10km circles of terrain and check how ‚flat‘ it is via their subjective angle raytracing measurement: https://www.disruptivegeo.com/blog/wp-content/uploads/2014/08/FlatMap_GeographicalReview_DobsonCampbell_2013Nov.pdf
They justify 10km as it’s how far a 6ft human can see on a flat portion of Earth. Fair enough, but I wanted to check other window sizes.
I also noticed they used the 90m resolution SRTM dataset, as opposed to the many higher resolution 30m resolution datasets that are out there (since well before 2014).

So, I checked both 90m and 30m datasets, using windows for each of 1km, 2km, 5km, 10km, and 20km. Turns out that, of all those 10 possibilities, they happened to choose the single one (90m resolution, 10km window) that shows the least ‚flat‘ ranking of Kansas, compared to all others that show a ‚flatter‘ ranking.

The results I posted in a comment below correspond to the mean, median, and 90th percentile rankings of how ‚flat‘ all the windows of a given state are, by least mean squares flatness; in my case, I’m using the 30m resolution dataset with a 2km window.

Just from my own personal opinion, this seems more realistic, yeah parts of California are flat as a pancake, but it’s a bit of a stretch to call it an average flatness state of the contiguous 48 haha.

EDIT: parentheses numbers are Dobson’s rankings, the first set of numbers are my rankings from median window flatness.

Where are Alaska and Hawaii 😩

As a Tennessean, I have always thought of North Carolina as more mountainous than Tennessee, due to, well, it having more mountains, and many are taller, too.

It’s totally bullshit how they get ocean access *and* more, taller mountains than Tennessee. We have nothing.

[Kansas is Flatter than a Pancake](https://bpb-us-e1.wpmucdn.com/blogs.uoregon.edu/dist/e/9870/files/2014/11/pancake1-1oafiyx.pdf)

Honestly when I looked at the first one I was like „Man, Colorado is getting done dirty.“

Then when I look at this one I think „Man, Colorado still getting done dirty.“

I know Montana, Wyoming, and Colorado have some pretty flat East sides… but they’re also home to some of the most extreme mountains in the world.

This is a criminally underrated post for all the effort that went into it

As a North Dakotan I approve. Last week I watched my dog run away for 3 days straight. On the third day my neighbor let her in

*48 out of the 50 US States

Thanks for this. Haven’t checked it all out, but I’ve grown up and lived in the west for years, my first red flag was that oregon was supposedly less flat than Washington. Anyone that has traveled those 2 states knows that can’t be true. 

Delaware is very very flat. It’s only hills are up near the PA line and they are just creek valleys.

Now we wait to see if anyone is petty enough to take it down to a county level

Honestly as someone from the Midwest I was a bit surprised by how „unflat“ some Midwest states were. I am sure parts of the state was doing the heavy lifting but still.

How is Rhode Island less flat than North Carolina?

It’s a bit a surprise that Georgia’s closer to Mississippi than it is to Alabama, considering how different Mississippi is in a physiographical sense from AL, GA & SC. Then I look at a [topographical map](https://cecas.clemson.edu/geolk12/semaps/seregional/screen/digielmap.jpg) and remember why.

Most southern states are basically a gradient from the Appalachians to the coast (or Mississippi River in Tennessee’s case). Florida grabs a lot of the ocean flat zone Alabama would’ve had (though to be honest, if Alabama did have the panhandle, that lowest plain area would still be a low proportion of area since it doesn’t go as far inland as would other states). What Alabama does weird is that it’s low area is more tied to the Mobile River Basin that’s below the Fall Line. So besides the coastal areas and delta, the Black Belt that’s in the south central part of the state is the lowest. If the speckles of
green don’t imply it, that brown zone in the north central part of the state is at the higher side of brown near green in the areas getting closer to the Black Belt. South of the Black Belt, elevation also rises again outside of the Mobile Basin rivers.

So NC and AL are a bit of outliers from the rest of the coastal Southeast for different reasons: NC has a bit of an outlier highest high end for its gradient, and AL just said „Eff this gradient.“ Mississippi kept the Alabama attitude but has the Mississippi Delta and no Appalachian physiography (nor does it go as hard as AL does with the Black Belt), so it just ended up similar to GA & SC instead of LA.