The road grid system.... logical?
Oct 30th 2012, 7:06 am
#16
Septicity
Joined: May 2004
Posts: 23,762
Re: The road grid system.... logical?
Here's a weird one for ya.
Look at the squares a couple of miles below and above approximately US 60 in the east valley.
https://maps.google.com/maps?hl=en&l...32093&t=m&z=14
Notice they don't quite line up vertically. Then look for the obvious kinks in many of the main north/south roads around Baseline.
This is the correction for the curvature of the earth.
Weird, eh?
Look at the squares a couple of miles below and above approximately US 60 in the east valley.
https://maps.google.com/maps?hl=en&l...32093&t=m&z=14
Notice they don't quite line up vertically. Then look for the obvious kinks in many of the main north/south roads around Baseline.
This is the correction for the curvature of the earth.
Weird, eh?
Oct 30th 2012, 1:59 pm
#18
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Joined: Nov 2002
Location: Where bad things rarely happen in movies
Posts: 8,933
Re: The road grid system.... logical?
Ahhhh... is that nationwide generally? And what about number sequences? Because sometimes you can come up to an intersection with a road sign saying "Avenue Road 12300" and not know whether 12345 is to the right or to the left.
Generally speaking I do find things easier to, um, find here though.
Generally speaking I do find things easier to, um, find here though.
Oct 30th 2012, 2:10 pm
#19
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Joined: Nov 2002
Location: Where bad things rarely happen in movies
Posts: 8,933
Re: The road grid system.... logical?
[QUOTE=guitarmaan;10356817]
If any Americans are laughing at this point, take pity on me. I'm a newbie
QUOTE]
Gotta remember.....these are folk who still class Maryland and Delaware as "south", but exclude the 2 southernmost states from the "Deep South" so take their map directions with a pinch of salt
. I tried explaining the background to my (then) 1st grader and he ended up deciding that he would use a different compass depending on whether he was doing geography or history
If any Americans are laughing at this point, take pity on me. I'm a newbie
QUOTE]
Gotta remember.....these are folk who still class Maryland and Delaware as "south", but exclude the 2 southernmost states from the "Deep South" so take their map directions with a pinch of salt
. I tried explaining the background to my (then) 1st grader and he ended up deciding that he would use a different compass depending on whether he was doing geography or history
Oct 30th 2012, 2:28 pm
#20
BE Enthusiast
Joined: May 2011
Posts: 860
Re: The road grid system.... logical?
Edited to cover my shame ! ;-)
I should of course have used the great circle method. At Phoenix's latitude, the distortion relating to the earth's curvature is more like 0.01%, which is hardly noticeable on a map.
Perhaps 19th century surveying errors are to blame for the kink?
I should of course have used the great circle method. At Phoenix's latitude, the distortion relating to the earth's curvature is more like 0.01%, which is hardly noticeable on a map.
Perhaps 19th century surveying errors are to blame for the kink?
Last edited by FlyingDutchman6666; Oct 30th 2012 at 3:03 pm. Reason: .
Oct 30th 2012, 2:30 pm
#21
Septicity
Joined: May 2004
Posts: 23,762
Re: The road grid system.... logical?
The metro Phoenix grid really isn't a small scale.
Oct 30th 2012, 3:08 pm
#22
Lost in BE Cyberspace
Joined: Mar 2010
Location: Phoenix, AZ
Posts: 8,106
Re: The road grid system.... logical?
The trick with Phoenix metro is knowing the through roads. Certain main thoroughfares go all the way across others don't due to mountains canals and Airports for example. I recall one of our early house hunting trips we thought we had it down just had to turn right and we were there. Mountain says NO! You learn other things too like avoiding Scottsdale old town particularly during spring training.
Oct 30th 2012, 3:46 pm
#24
Septicity
Joined: May 2004
Posts: 23,762
Re: The road grid system.... logical?
Edited to cover my shame ! ;-)
I should of course have used the great circle method. At Phoenix's latitude, the distortion relating to the earth's curvature is more like 0.01%, which is hardly noticeable on a map.
Perhaps 19th century surveying errors are to blame for the kink?
I should of course have used the great circle method. At Phoenix's latitude, the distortion relating to the earth's curvature is more like 0.01%, which is hardly noticeable on a map.
Perhaps 19th century surveying errors are to blame for the kink?
Oct 30th 2012, 3:49 pm
#26
Member
Joined: Apr 2001
Posts: 14,049
Re: The road grid system.... logical?
It may not happen in the expansive west, but in the compact and congested northeast you'll find many highways where when driving on Rt X North you are heading south, or when driving on Highway Y East you are heading west, and vice versa. The reason being that the compass designations are based on the overall direction of the full road, but due to geography some local sections of the road have reversed direction and are running the opposite way.
Regards, JEff
Regards, JEff
One thing I assumed when heading to the US is a simpler, more logical road layout compared to the UK. And sure enough, American roads (in Arizona) are mostly laid out in a grid. Compared to the UK mess, it's a "cakewalk".
However, hopefully someone can explain something to me. And perhaps I'm missing something obvious. But when a road is split between North and South, surely the the "North" part should be closer to the North pole, and the "South" part be closer to the South pole?
I ask because apparently this is not the case. An example being, S and N Rural Road in Tempe/Chandler AZ. Looking at google maps, S Rural Rd is above N Rural Rd. How can that be? Google maps is obviously laid on North top and South bottom. So Rural Rd should be N at top and S at bottom. No?
However, hopefully someone can explain something to me. And perhaps I'm missing something obvious. But when a road is split between North and South, surely the the "North" part should be closer to the North pole, and the "South" part be closer to the South pole?
I ask because apparently this is not the case. An example being, S and N Rural Road in Tempe/Chandler AZ. Looking at google maps, S Rural Rd is above N Rural Rd. How can that be? Google maps is obviously laid on North top and South bottom. So Rural Rd should be N at top and S at bottom. No?
Oct 30th 2012, 3:59 pm
#27
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Joined: Nov 2002
Location: Where bad things rarely happen in movies
Posts: 8,933
Re: The road grid system.... logical?
Oct 30th 2012, 4:08 pm
#28
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Joined: Feb 2011
Location: WA state
Posts: 3,063
Re: The road grid system.... logical?
My street address ends in NE but I live in the NW of the city. This is because when the streets were built they were part of the city to the west, and were later incorporated into the much closer city to the east.
There is a street near me called 124th Ave NE. It intersects at a right angle with a street called NE 124th St in the middle of a business area. Causes lots of problems for directions.
Around here, north-south roads are Avenues and Drives, east-west roads are Streets and Places. Not always true though. No idea how the numbering system works. I have a narrow plot and the house number next door is about 8 more than mine! No wonder it gets into the thousands so easily. The thing I hate about the grid system is that roads end at one point and start up with the same name a few miles away. Without knowing the cross-streets you have no idea which road is the correct one.
There is a street near me called 124th Ave NE. It intersects at a right angle with a street called NE 124th St in the middle of a business area. Causes lots of problems for directions.
Around here, north-south roads are Avenues and Drives, east-west roads are Streets and Places. Not always true though. No idea how the numbering system works. I have a narrow plot and the house number next door is about 8 more than mine! No wonder it gets into the thousands so easily. The thing I hate about the grid system is that roads end at one point and start up with the same name a few miles away. Without knowing the cross-streets you have no idea which road is the correct one.
Oct 30th 2012, 4:19 pm
#29
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Joined: May 2011
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Re: The road grid system.... logical?
The distance between meridians changes with the cosine of the latitude - approximately, if the earth were a perfect sphere. So the *change* in distance between meridians changes with the sine of the latitude. At Phoenix's latitude, that would correspond to 1km per degree of latitude (111km). So 1%.
On a map of Phoenix, I count approx. 35x35 squares (square miles?). So to correct for the curvature, North Phoenix should be 1/3 square narrower than South Phoenix. If the correction is applied at two lines, say Baseline and Bell, the squares should narrow by 1/6 of a mile there - 300 yards - quite noticeable. And exactly the order of magnitude we see on the map !
So you might very well be correct.
I wonder what would happen in naive grid systems that didn't correct for the curvature of the earth. Presumably, land subdivisions would get smaller and smaller the further north you go. Not ideal for land owners to keep track of?
Last edited by FlyingDutchman6666; Oct 30th 2012 at 4:21 pm.
Oct 30th 2012, 4:29 pm
#30
Septicity
Joined: May 2004
Posts: 23,762
Re: The road grid system.... logical?
Let's see where my very naive back-of-the-envelope calculation take us.
The distance between meridians changes with the cosine of the latitude - approximately, if the earth were a perfect sphere. So the *change* in distance between meridians changes with the sine of the latitude. At Phoenix's latitude, that would correspond to 1km per degree of latitude (111km). So 1%.
On a map of Phoenix, I count approx. 35x35 squares (square miles?). So to correct for the curvature, North Phoenix should be 1/3 square narrower than South Phoenix. If the correction is applied at two lines, say Baseline and Bell, the squares should narrow by 1/6 of a mile there - 300 yards - quite noticeable. And exactly the order of magnitude we see on the map !
So you might very well be correct.
I wonder what would happen in naive grid systems that didn't correct for the curvature of the earth. Presumably, land subdivisions would get smaller and smaller the further north you go. Not ideal for land owners to keep track of?
The distance between meridians changes with the cosine of the latitude - approximately, if the earth were a perfect sphere. So the *change* in distance between meridians changes with the sine of the latitude. At Phoenix's latitude, that would correspond to 1km per degree of latitude (111km). So 1%.
On a map of Phoenix, I count approx. 35x35 squares (square miles?). So to correct for the curvature, North Phoenix should be 1/3 square narrower than South Phoenix. If the correction is applied at two lines, say Baseline and Bell, the squares should narrow by 1/6 of a mile there - 300 yards - quite noticeable. And exactly the order of magnitude we see on the map !
So you might very well be correct.
I wonder what would happen in naive grid systems that didn't correct for the curvature of the earth. Presumably, land subdivisions would get smaller and smaller the further north you go. Not ideal for land owners to keep track of?