A township could not be exactly six miles on each side
December 10, 2015 4:05 PM   Subscribe

Grid corrections : places where North American roads deviate from their otherwise logical grid lines in order to account for the curvature of the Earth. You could drive out there your whole life, de Ruijter realized, and not realize that certain stop signs and intersections exist not because of eccentric real estate deals, but because they are mathematical devices used to help planners wrap a rectilinear planning scheme onto the surface of a spherical planet.
posted by desjardins (41 comments total) 67 users marked this as a favorite
 
In his 2004 book Correction Lines, author Curt Meine explains that these are “places where theory and reality meet." His book uses them as a metaphor for the idea that, in the real world, a perfect plan must always be imperfectly implemented.
"Heh," notyou said before closing the tab and returning to work on the spreadsheet.

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Great photos! Thanks for sharing them!
posted by notyou at 4:13 PM on December 10, 2015 [2 favorites]


Neat! Take that, fifth postulate!
posted by painquale at 4:24 PM on December 10, 2015 [2 favorites]


holy crap that's fascinating.
posted by Annika Cicada at 4:29 PM on December 10, 2015 [1 favorite]


Surely it would have been easier to just redefine the mile to take latitude into account. It's not like Jefferson envisioned the purchase of Alaska, anyway.
posted by Joe in Australia at 4:30 PM on December 10, 2015 [1 favorite]


...vision of six-square-mile township parcels...

A rectangle that's 6 miles per side is 36 square miles, not 6.

That's why each survey township is divided into 36 "sections" of a square mile each.
Author should have got the 2d terminology right before trying to deal with the actual 3d case.

That said, I found this fascinating.
posted by w0mbat at 4:33 PM on December 10, 2015 [4 favorites]


Michigan is the only state with two baselines. Some inaccurate work resulted in survey townships west of the meridian intersecting the meridian some 936 feet south of the initial work.
posted by quonsar II: smock fishpants and the temple of foon at 4:34 PM on December 10, 2015 [2 favorites]


Isn't this how Lake Wobegon happened?
posted by scalefree at 4:51 PM on December 10, 2015


I wish he'd given more visual context. Seeing a road not line up is less impressive without seeing it trace a dead-straight 30 mile path before and after that.
posted by agentofselection at 4:53 PM on December 10, 2015 [4 favorites]


Mesa is one of the easiest places to see this. Go into Google Maps, head on over to Mesa and take a look at everything directly south of US Route 60. There's realignments as far as the eye can see!
posted by Talez at 4:55 PM on December 10, 2015 [6 favorites]


That's neat: I like how sometimes the realignment jogs are north of Baseline Road, others are south of it. Also I'm getting the eye-twitches out of how many of those neighborhoods have the car-centric twisty, non-connecting streets.
posted by traveler_ at 5:06 PM on December 10, 2015 [1 favorite]


THIS IS AWESOME
posted by shakespeherian at 5:27 PM on December 10, 2015


Yes- the photos, in the article at least, do not make it plain what he's talking about. I understand pictures better than words and there aren't proper pictures here, not for explication, though they're pretty.

So where's Mesa?
posted by Rich Smorgasbord at 5:27 PM on December 10, 2015 [1 favorite]


Arizona. It's part of the Phoenix metropolitan area to the east.
posted by Talez at 5:39 PM on December 10, 2015


This is cool, thanks for posting desjardins!
posted by carter at 5:45 PM on December 10, 2015


And here I ascribed the dogleg between the house and the high school I went to to drunken farmers or surveyors or some such.
posted by one weird trick at 6:04 PM on December 10, 2015


More seriously, if you're interested in the underpinnings of this, check out Measuring America
posted by one weird trick at 6:09 PM on December 10, 2015 [4 favorites]


Hmmm, I'll offer an amusingly skeptical take on the "the Earth's curvature made me do it!" premise. Seems as though good ol' human error and/or variations in surveying protocol from town to town can account for these sort of rectilinear breakdowns.
posted by Theophrastus Johnson at 6:50 PM on December 10, 2015 [3 favorites]


Yeah, I can't find it right now but Straight Dope had a piece on one in Chicago and concluded it was surveyor error. I would expect a lot of that.
posted by PMdixon at 6:53 PM on December 10, 2015


(like I'm not saying all the 19th century surveyors were drunk all the time but I'm not not saying it)
posted by PMdixon at 6:56 PM on December 10, 2015 [5 favorites]


The first thing I thought was "Phoenix", because Phoenix is serious about their grid. You start seeing streets named according to their grid system before you are anywhere near the city.
The second thing I thought was "seriously, they don’t have a way of taking this into account?". And then I saw the Straight Dope links.
posted by bongo_x at 7:29 PM on December 10, 2015


I thought there'd be more gore-y details than that, but I am a New Englander.
posted by Earthtopus at 7:41 PM on December 10, 2015 [2 favorites]


This is one of those things I didn't realize people didn't know about, until I moved into the city and learned that most people do not spend a lot of time driving rural roads. The road to my parents acreage has a correction that always screws me up, not it getting to my parents place but in remembering where they live. Because of the correction, and because they live east of me, I always turn down one range road and jog over to the next, going from 232 to 233 at the correction. Whenever I go to their place from not my house I almost always turn down the wrong range road and immediately feel foolish, especially if there other people in the car.

Seems as though good ol' human error and/or variations in surveying protocol from town to town can account for these sort of rectilinear breakdowns.

I can't speak for all rectilinear breakdowns, but proper correction lines are definitely not due to the local stupidity of townies. At least with the Dominion Land Survey, which surveyed Manitoba, Saskatchewan, and Alberta into townships and which I'm most familiar with since this is where I live, the correction lines were put in by design at the beginning. They weren't added after the fact to appease the locals, as in many cases there either weren't any locals or they were deliberately ignoring the locals, e.g. the Metis settlers notably had all sorts of conflicts over their land rights when the survey came.
posted by selenized at 8:18 PM on December 10, 2015 [1 favorite]


Much of the eastern border of Saskatchewan is actually jagged for this reason.

Now that I have grokked Canada's epic geodetic hackfest (Not really! It's a thing of beauty!) well enough to implement software based on it, I'm noticing instances everywhere of the compromises people make to accommodate the challenges of our lumpy planet.

Legend has it that the University of Victoria is oriented on a slight angle because the surveyors forgot to account for magnetic declination.
posted by klanawa at 8:31 PM on December 10, 2015 [1 favorite]


I see these a lot in rural Missouri. I had always assumed it had to do with not putting roads through established agricultural and grazing plots.
posted by sourwookie at 8:40 PM on December 10, 2015


During the 1998 Ice Storm a couple of Intelligence officers were sent to my armoury with all the 1:50,000 maps of Quebec and told to make a giant map of the province; 72 maps high and 48 wide. Piece of cake! They took over the gym, trimmed all the edges of the maps and laid them out on the gym floor, lining everything neatly by the gridlines. They hadn't even made it to James Bay before they realized the folly of their plan.
posted by furtive at 9:36 PM on December 10, 2015 [11 favorites]


Thanks for this. I spent my early childhood in Northern Minnesota, where the landscape is dominated by the features of the Jeffersonian system. Our house was on the townline road, and one of my earliest memories is of asking what "the Jog" was.
posted by Maxwell's demon at 11:13 PM on December 10, 2015


I recall a scene from a novel or maybe a memoir where a character was riding a motorcycle wasted and like a bat out of hell down one of these long straight roads at night on autopilot and then wound up seriously damaged from a cornstalk through his palate into his brain pan when he missed the jog at 90 mph. Or, something like that. And, it is bugging the hell out of me that I can't remember which book. Halp.
posted by Gotanda at 1:19 AM on December 11, 2015 [1 favorite]


The omnipresent grid is one of the things that really messed with my brain when I lived in California. I realised how much I used the shape of streets in Europe to orientate myself. Often in San Francisco I'd emerge from the BART and have no idea which way I was facing because everything looked the same. At least in Berkeley everything was on a slant from the Berkeley Hills to the Bay. What really threw me were all the rural roads in the Central valley being on a grid too. What conceivable benefit is there to driving at right angles in the middle of nowhere?
posted by kersplunk at 2:45 AM on December 11, 2015 [1 favorite]


The Beginning Point. Someday I may get around to stopping there.
posted by one weird trick at 4:53 AM on December 11, 2015


Legend has it that the University of Victoria is oriented on a slight angle because the surveyors forgot to account for magnetic declination.
St-Hilaire. And ... your players are all non-imports, right? Montrealers?

Troy. Of course. Delightful people.

I look over at St-Hilaire, and she's grinning. Uh-ohhhhh.

St-Hilaire. Magnetic north or Montreal-north?

Troy. What nonsense are you speaking of?

St-Hilaire. They're not the same thing. If you're a Montrealer, west is the mountain. East is Stade Olympique. South is the Saint-Laurent. So you figure out where North is.
posted by Mayor West at 5:19 AM on December 11, 2015 [1 favorite]


If it were deliberate (as opposed to surveyor error) then there should be somewhere where there are no corrections...

I wonder where the longest N-S stretch with no grid corrections is...
posted by sodium lights the horizon at 5:21 AM on December 11, 2015


I first read about this in the Neal Stephenson novel REAMDE. One of the secondary characters crashes a motorcycle into a cornfield because he was speeding on a long stretch of road and missed the east/west bit of road
posted by JDHarper at 6:11 AM on December 11, 2015 [1 favorite]


Here is a nice set near me. If you scroll left and right on about 43.5 LAT, there's more than a dozen, all lined up together.

Around here, these corrections frequently happen with no intersecting roads at all.
posted by yesster at 6:37 AM on December 11, 2015 [1 favorite]


yesster - in your example, there appear to be jogs both ways. Anyone know what's up with that?
posted by carter at 6:42 AM on December 11, 2015


Actually, it's cool, if you zoom in to yesster's example, you can see where there are two different grids meeting each other (I think).
posted by carter at 6:45 AM on December 11, 2015


And if you follow the 43.5 LAT line to the east of Sioux Falls, it forms the border between MN and IA, where there are lots of corrections going both ways.
posted by yesster at 6:53 AM on December 11, 2015


I've always loved this stretch of road in northern MN; because the jog happens at a county line, I always assumed it was a surveying mistake. Now I'm curious to know if it was actually intentional.
posted by Ickster at 7:29 AM on December 11, 2015


I have nothing to say other than "great link, thanks" but I feel eponysterically obligated to comment in this thread.
posted by theodolite at 8:06 AM on December 11, 2015 [5 favorites]


I always naively assumed the jogs way out in the middle of agricultural bucolia were the land-surveyor equivalent of drilling a tunnel from two ends and hoping it meets in the middle.

Or the local planning department passively enforcing an unposted speed limit.
posted by a halcyon day at 12:00 PM on December 11, 2015


I first read about this in the Neal Stephenson novel REAMDE.

huh: "It seemed that his nocturnal ride had been terminated by a sudden west-ward jog in the section-line road. Failing to jog, he had flown off straight into the cornfield, doing something like ninety miles an hour... so he had devoted a lot of attention to the question of why the transit-brandishing pencil-necks who had laid out the section lines a hundred years ago had been so particular about sticking to a grid pattern and yet had perversely inserted these occasional sideways jogs into the grid. Examining maps, he noticed that the jogs only occurred in north-south roads, never east-west. The answer, of course, was that the earth was a sphere and so it was geometrically impossible to cover it with a grid of squares. You could grid a good-sized patch of it, but eventually you would have to insert a little adjustment: move one row of sections east or west relative to the row beneath it."
posted by kliuless at 6:24 PM on December 11, 2015 [2 favorites]


The hairy ball theorem at work!
posted by jpdoane at 8:34 PM on December 11, 2015 [1 favorite]


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