The Chainlink

2013 Chicagoland Bike Map is distorted

While waiting for the snow to melt, I've been looking at my new Chicagoland Bike Map from the Active Transportation Alliance.

What was the ATA thinking?  They have published a map that is badly distorted, not drawn to scale.  The purported scale is 1" on the map equals 1.5 miles on the ground. That scale holds true for the North-South dimension, but not for the East-West dimension.  

Take any known mile and a half distance in a north-south direction, say Addison to Lawrence.  That measures 1" on the map.  Now pick a known mile and a half distance in an east-west direction.  Say Kedzie to Damen.  That measures almost  1-5/8" on the map.  

And it's like that everywhere.  Take a known mile square.  Say from Lincoln-Belmont-Ashland to Lincoln-Fullerton-Halsted.  Belmont to Fullerton is a mile, Ashland to Halsted is a mile.  On any other map, Lincoln Ave. between these two points is a 45 degree angle.  Not on this map.  The Belmont-Ashland-Fullerton-Halsted square is a rectangle with a ratio of 8:5 instead of 1:1.

What bizarre kind of map projection is this?  Did the ATA cartographers have to yield to the ATA graphic designers, who decided to junk the aspect ratio to fit the planned size of the map?

This should not have happened.

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Permalink Reply by Skip Montanaro 0mi on March 7, 2014 at 11:42am

Does seem weird...

Permalink Reply by Kevin C Dormant on March 7, 2014 at 11:46am

I hope they got a good deal on the printing cost.

Permalink Reply by Mike Zumwalt on March 7, 2014 at 12:24pm

What's with all the measuring?

The grid is every 800 in numbers equals a mile and every destination has an address.

But if you give more than an inch do you get more than a mile taken?

Permalink Reply by Steve Cohen on March 7, 2014 at 12:33pm
What's with all the measuring?

Any map I've ever seen uses the same scale in both dimensions. Anyone trying to use this map and its purported scale to plot the distance of a ride will not get accurate results unless the route is strictly north-south. It may not be the most important thing in the world, but must all our technology continue to make us stupider by the minute?

I'm not sure this even qualifies as a "map". "Map-like graphic" would be more accurate. But it's sold as a map.
Permalink Reply by Steve Cohen on March 7, 2014 at 12:48pm
Actually it makes east-west rides appear longer.
Permalink Reply by Andrew Bedno on March 7, 2014 at 12:50pm

Wow, can't wait to see it to confirm, but sounds truthy.  Anyone got a PDF link for that?  I didn't find one in a cursory look.

Permalink Reply by Steve Cohen on March 7, 2014 at 12:57pm
You have to look on the printed map. Anyone could change the aspect ratio on the graphic to fix it and put it in a PDF but I'm talking about what they released. Mono truthiness here, Andrew. It's for real.
Permalink Reply by Steve Cohen on March 7, 2014 at 12:58pm
Stupid iphone. I wrote "no truthiness here"
Permalink Reply by Steve Cohen on March 7, 2014 at 1:32pm

Actually, it's the map that's truthy.  :-)

Permalink Reply by Lisa Curcio on March 7, 2014 at 1:35pm

And doesn't the Chicagoland map include suburbs where the Chicago grid system disappears into the hell of the windy streets and lack of numbering so even if you did not want to use the map to plot a route you cannot look at it and accurately get distance outside the city.  And what about angle streets in the city? 

Permalink Reply by Steve Cohen on March 7, 2014 at 1:49pm

Right, Lisa, it's wrong outside the city and it's wrong inside the city.  No angle streets are to scale.  The further they are from straight north-south the more out of scale they are

Lisa Curcio 4.1 mi said:

And doesn't the Chicagoland map include suburbs where the Chicago grid system disappears into the hell of the windy streets and lack of numbering so even if you did not want to use the map to plot a route you cannot look at it and accurately get distance outside the city.  And what about angle streets in the city? 

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Permalink Reply by S on March 7, 2014 at 1:52pm



Mike Zumwalt said:

What's with all the measuring?

The grid is every 800 in numbers equals a mile and every destination has an address.

That's not true.  Madison to 31st has some odd numberings, e.g. Roosevelt is a mile south of Madison but is 1200 S.   But in general 800 to a mile is accurate and as far as I know, it's accurate in the east-west direction. 

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