Sunday, February 6, 2011

Mysterious Lines on Google Maps

While finding geocoordinates for Wikipedia this afternoon, I ended up looking for a mountain called Soapstone Mountain in northeast Connecticut. While I was at it, I noticed something very incongruous - a completely straight-line road:


There's actually two in that image; a longer one at top, and a shorter one crossing I-84 at bottom. Both are roughly east-west, but are tilted a few tenths of a degree.

But, when I turned to satellite mode, I realized something even stranger: they don't exist. The supposed streets run through empty land and thick forests; no property boundaries indicate the right-of-way even existing.

Then I started looking for more; I found another - a fake spur off MA-146, southeast of Worcester in south-central Massachusetts:


Although they are marked as roads, the mapping algorithm doesn't treat them as such, and it's not possible to use them as part of a route:


They also are intentionally disconnected at their ends:


These don't seem like the sort of things that could be mistakes. I would guess that they are fictitious entries called trap streets, designed to allow Google to detect if someone is illegally copying their maps. However, it would seem like they would use less-obvious trap streets, instead of large straight lines.

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