Growing up in the USA or Canada, we were used to maps overprinted with house address coordinate grids. Figure 1:
(圖 Image: 紅色為 S. St. Paul, Minnesota, USA 中有條無紊的門牌座標。 美、加做得到. House numbering system in red.)
Image: A map of this part of Lake County, Illinois, USA, showing Lake Forest, Highland Park (oblique), and greater Deerfield area addressing grid ticks, in red.
But well gosh, we've seen tons of web maps, you know, OpenStreetMap, Google Maps, etc. But no grids.
Sure, plenty of individual house number points, and even ranges, but no grids.
Article half-baked. Read at own risk.
Yes, we often can see a reading of where our cursor is, and in e.g., Google Earth we can checkmark "View > grid" (CTRL+L) but that's just latitude and longitude.
Even many N. American cities don't have dominant street directions.
And even then, cities like St. Catherines Ont. just stick to "one street, one grid."
So how are we going to enable web maps to have grids like back in figure 1?
Well, each town needs its own EPSG-style
grid definition! That way web developers would have a standard
way to get the definition they need to display the grid in
whatever fashion they want, or even just compute estimated house
numbers, given a certain longitude and latitude.
Big mistake... many of these grids are simply PLSS based. So that's what we need to attach to when creating grids. Else it's never going to fit just right.
In simple terms, (0, 0) is at the corner of State and Madison Sts., 800 numbers per mile, with some quirks. PLSS based, so we any address grids we make should also be.
Like Chicago, but with a non-perpendicular address grid axes:
"This Easterly Base Line shall extend northwesterly..." [Article V. - System of Street Numbering]
Oblique 100's grid ticks in red, seen in this late 1990's street map, showing the southeast tip of Highland Park, Illinois.
Image: Here is a tiny piece of the address grid Fire District map of Highland Park, Illinois, We observe the house addressing grid, with graticules every 100 house numbers.
Not only is an axis skewed from north, to follow the lakeshore, as specified in the City Code, but it also makes an oblique angle with the other axis. (The red numbers ("3408") are fire district (34,) and subdistrict (08,) numbers.)
State and province wide addressing systems pose their own difficulties to straight numerical conversion without post processing. First although Public Land Survey System and Dominion Land Survey based grids might be OK over the area of a city, going much farther hit various correction line jogs, etc.
Yes, even if South Dakota's system seems so ideal even over North Dakota's, with the latter's quadrants. But still they are all PLSS based.
So... we simply need to give up our projection based EPSG concepts, and use a PLSS based approach!
Even supposing a perfectly surveyed PLSS, these delightfully ingenious systems would still require post processing:
Manitoba neighbors' 12159, 13001 discontinuity arises from miles in the front, and (the last three digits) 2 decameters (/2 odd/even) in the back.
Saskatchewan neighbors' 316580, 317002 discontinuity arises from int( 1609(m/mi) / 40 / 2(odd/even)) and there only being six miles width in a DLS township so we have jumped from R16W to R17W. The 3 at front is the 3rd Principal Meridian -- which indeed makes that system potentially able to be extended throughout western Canada!
So... custom postprocess them!
And there will always be more local issues,
Yes, there are plenty of situations that violate the grid, like as Highland Park, Illinois rules says, streets that double back on themselves, like its Highland Place, continue the numbering regardless. Makes sense to the man in the street walking down the block.
Then there is even Ridge Road, made with two nearby overlapping (Y coordinate) pieces with numbers that carefully don't overlap -- due to plenty of room in the 800 numbers per mile system.
Here we take various approaches. They are in order of when I wrote them. Hence they will go from crude to more refined.
Also I am/will redo(ing) many of these with a new PLSS-based point of view...
Glencoe, IL. first attempt mock-up, 8/2023.
Evanston, IL has a grid tilt downtown...
Wilmette, IL turned out to have irregularities (hand made address "contours" map,) so we gave up on it.
While I am writing there here are some places to tailor to:
Kane Co. IL: "05N150"
Menomonee Falls, WI: W156 N8480.
https://www.co.dunn.wi.us/ruraladdressing: 400 house numbers in every mile, 40 road numbers in every mile.
I bet my province-wide (Sask.) computations would fall apart because errors would build up over such long distances...
Utah addresses are unique from other states because of a strong address grid system. The address grid system enables us to make special assumptions and optimizations to address finding processes used by the geocoding api...
The reader can use the sitemap to navigate the tree of (incomplete) city/county/state etc. mapping experiments I am doing.Dan Jacobson
More addressing articles by me.
Last modified: 2023-11-23 00:53:10 UTC