I recently learned that map makers intentionally put fake roads, etc., into their maps to identify copyright infringements (when maps are stolen, even the errors are reproduced). These are called copyright traps. I grew up outside of Chicago near Ohare International Airport. I heard that Rand McNally once put a fake town near Ohare in their maps. I checked up on it and and found that it is true. The fake town is called Westdale and it appeared in the 1981-1983 editions of Rand McNally’s maps. Westdale is near a “Westdale Park” and a “Westdale Elementary School” (see it on google maps here).
Here is a link to more on copyright traps from the Straight Dope (the 1991 edition). This author was skeptical about the existence of the fake Chicago suburb, but it was written before google. I found the rest of the information to be interesting.
Punk Rock Operations Research 
January 3rd, 2012 at 11:03 am
We have the same in the UK. Several maps used to show a short road about 200 yards from my home as “Deneleigh Close” while its correct name is “Leighdene Close”. It was a “copyright trap”. The wiki http://wiki.openstreetmap.org/wiki/Copyright_Easter_Eggs has some others. I speculate that the coming of the internet has meant that map-makers now resort to false information, rather than “simple” errors like the Deneleigh/Leighdene change, because the residents can go online and ask for corrections. A fake road or housing can stay for several years. There are several examples of fake buildings and areas of woodland on UK Ordnance Survey maps noted by photographers on the “Geograph” project. (e.g. http://www.geograph.org.uk/photo/608925)
Now for the O.R. question: what is the optimal density of fake information on maps? How many pieces should there be on a map covering a US state or UK county? Too many and the maps may not be trusted, too few and the map can be copied. And who has the job of checking for plagiarism?
January 4th, 2012 at 2:35 pm
You sure Westdale wasn’t our version of a Potemkin village?
January 6th, 2012 at 10:40 am
“what is the optimal density of fake information on maps?”
@David: this sounds like a fun project for a capstone course in operations research! It depends on the granularity of the map.
There are consequences to too many copyright traps. Roads that are thru-streets on the map but dead ends in reality are problematic. Large trucks that have to turn around at the dead end can really damage a road. I’ll put that into my optimization model 😉