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  #1  
Old 11-06-2009, 01:51 PM
happywaffle happywaffle is offline
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Is the MT-WY-SD border really weird like this?

Just doing some Google Maps browsing when I came to this odd sight:
http://tinyurl.com/yae7rst

Did the cartographers get drunk when they drew these borders? Or the Google Maps cartographers, maybe? Any northerners who can lay some insight? This border seems like it could be perfectly straight...
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  #2  
Old 11-06-2009, 02:54 PM
Keeve Keeve is offline
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Pretty wierd. Bing (previously MSN) maps shows it slightly differently.

On Google maps, the NW corner of South Dakota is about 10 yards further north than the NE corner of Wyoming, and the WY/SD border seems to go due north.

On Bing and MapQuest, those two corners meet at the same point, but the northernmost 50-yards veers off to the east a bit.
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  #3  
Old 11-06-2009, 03:10 PM
GreasyJack GreasyJack is online now
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Here's your answer: http://www.blm.gov/cadastral/meridians/pmmap.jpg

In addition to being where three states intersect, it's also where three different meridian/base line groups come crashing together. I imagine it doesn't help that the Wyoming part is actually surveyed to a base line that's to the east of the one where western South Dakota is surveyed to.

When you combine these three different variations of reconciling a square grid pattern over a three dimensional spheroid planet, and you throw in variations in elevation as well, it's a wonder that those lines are as straight as they are!
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  #4  
Old 11-06-2009, 03:16 PM
Keeve Keeve is offline
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Quote:
Originally Posted by GreasyJack View Post
yow! look what's going on in ohio!
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  #5  
Old 11-06-2009, 03:31 PM
panache45 panache45 is offline
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I know that Congress had intended the southern border of Montana (then part of the Idaho Territory) to fall exactly halfway between the borders of Colorado and Canada, along the 45th parallel. But somehow little discrepancies occurred, like the one a little further west, where the border crosses the Powder River. As is, the segments don't even seem to be parallel, and that 10-yard discrepancy is indeed weird.
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  #6  
Old 11-06-2009, 03:38 PM
panache45 panache45 is offline
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Quote:
Originally Posted by Keeve View Post
yow! look what's going on in ohio!
This explains a lot of what goes on in this state.
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  #7  
Old 11-06-2009, 03:38 PM
Keeve Keeve is offline
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Maybe this is off topic, but does anyone know where the data comes from? It seems that Bing and MapQuest are getting there data from a common source, and Google from elsewhere. I have noticed similar discrepancies elsewhere.
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  #8  
Old 11-06-2009, 03:56 PM
Spavined Gelding Spavined Gelding is offline
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Quote:
Originally Posted by Keeve View Post
yow! look what's going on in ohio!
Ohio is a special case. It was surveyed as a bunch of separate private acquisitions from the US in the years just after the American Revolution (think Northwest Ordinance). The northeast corner around Cleveland was surveyed off for bonus payments to Connecticut soldiers in the Revolution as Connecticut”s Western Reserve, thus the name of the university now merged with Case University. The southeast corner was surveyed off for General Putnam’s Ohio Land Company, the initial organized settlement on the right bank of the Ohio. The southwest up the Great Miami River (another college name) was sold off to the Miami Company. Somewhere at the north edge of the Miami survey is the Ludlow Line which passed just east of my childhood home and where Crafter Man still lives.

After the Ohio experience the US went with territory wide rectangular surveys. Right now, and for the past 35 years I have lived in far northeastern Iowa, in Township 94 North and Range 8 West of the 5th PM. That means that I live in a six square mile piece the southern boundary of which lies 564 miles north of an east-west line through central Arkansas and the eastern boundary of which lies 48 miles west of a north-south line through eastern Iowa, Missouri and Arkansas. It is a much more rational system than trying to deal with trees tied in knots and engraved stones and terribly simplifies land descriptions.

This area and most of southern Minnesota was surveyed in 1848.
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  #9  
Old 11-06-2009, 04:29 PM
Chronos Chronos is offline
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Quote:
The northeast corner around Cleveland was surveyed off for bonus payments to Connecticut soldiers in the Revolution as Connecticut”s Western Reserve, thus the name of the university now merged with Case University.
Nitpick: Case School of Applied Science. They merged with Western Reserve University (whose name has the history you mentioned) to form Case Western Reserve University.
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  #10  
Old 11-06-2009, 04:31 PM
Irishman Irishman is offline
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The deviations from N/S or E/W appear to be the effect of surveying errors, where the different surveys intersect.

The bigger question is why the two maps depict the borders differently.

Google has the eastern Montana/South Dakota border deviating inward from the survey line, then the southernmost 200 ft take a jog east. Bing shows that border straight, no jog.

Similarly, google shows the southern Montana/South Dakota line to be straight and intersect the Wyoming/South Dakota border north of the Montana/Wyoming line. Bing shows the intersection at one point, but the M/SD line runs slightly northward to the corner of the survey point where the border turns north, and the W/SD border takes a jog for the northernmost 50 yards.

Is this a case of map copyright traps?
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  #11  
Old 11-06-2009, 05:41 PM
GreasyJack GreasyJack is online now
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Here's the USGS Topo map(s) that show the area with all the various survey markers: http://www.topoquest.com/map.php?lat...=zoomin&size=l

Especially note the WY/SD border where the section boundary lines aren't quite parallel and the MT/WY border where the sections don't line up right. It looks like they even had some trouble stitching the maps together-- notice how some of the contours don't line up.
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  #12  
Old 11-07-2009, 08:58 AM
happywaffle happywaffle is offline
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Heh, it looks like nobody knows where the borders are! I'm gonna claim a chunk of land there and start my own country.
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  #13  
Old 11-07-2009, 11:09 AM
74westy 74westy is offline
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The data doesn't want you to zoom in that far.

GreasyJack's USGS map is more likely to be accurate than google boundaries of unknown provenance. I don't know much about where google's data come from but I did find this page saying that they get it from a company called TeleAtlas. That is apparently out of date and google now uses in house data for the US in part because TeleAltlas's US data was often inaccurate.

That's a long winded way of saying I googled around the problem and didn't find a precise answer so let the wild ass speculation begin.

Political boundary lines on a map are sequences of 2d points. These points could be gathered by precise land surveys, GPS surveys, digitized from paper maps, etc. and some of these methods are more accurate than others. Other problems with the data arise because there's more than one way to represent something on a map. The part of the US/Canada border that follows the 49th parallel is dead straight on a Mercator map but is curved on most other map projections. Data from different sources may be self consistent but don't match each other exactly. All kinds of problems.

Furthermore, data that's appropriate for a very large scale (like a map of a city) needs to have lines with a lot of points to give an accurate picture but very small scale (like a map of a large country) should have fewer points so that there isn't too much data to handle. What if you want to convert from small scale to large scale? Then you'll have to "generalize" the data i.e. filter out as many points as you can while still having a picture that's accurate enough for your scale.

I'm going to go out on a limb and guess that google uses US Census Bureau data for State boundaries. That information is pretty accurate when it's gathered but is then generalized for small scales between 1:500,000 to 1:5,000,000. The linked to google map looks like it's at a scale of about 1"=1000' or 1:12,000. In other words, those state boundaries probably look pretty accurate if you zoom out quite a bit but the picture we're looking at is zoomed in so far that we can see the inaccuracies and generalization of the data.
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  #14  
Old 11-07-2009, 05:49 PM
Hari Seldon Hari Seldon is offline
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Quote:
Originally Posted by Keeve View Post
yow! look what's going on in ohio!
Shades of the great Toledo war (which Ohio lost).
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  #15  
Old 11-07-2009, 06:31 PM
jayjay jayjay is offline
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Originally Posted by Hari Seldon View Post
Shades of the great Toledo war (which Ohio lost).
That's the one where Ohio and Michigan fought over who'd get stuck with Toledo, right?
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  #16  
Old 11-07-2009, 06:44 PM
Ponch8 Ponch8 is offline
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For more weirdness, check out the Colorado-Utah border on Google Maps, specifically about 80 or 100 miles north of the Four Corners. I'll bet you thought Colorado was perfectly rectangular (or at least as rectangular as you can get on the surface of a sphere).
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