In cartography, a trap street is a fictitious entry in the form of a misrepresented street on a map, often outside the area the map nominally covers, for the purpose of "trapping" potential plagiarists of the map who, if caught, would be unable to explain the inclusion of the "trap street" on their map as innocent. On maps that are not of streets, other "trap" features (such as nonexistent towns, or mountains with the wrong elevations) may be inserted or altered for the same purpose.[1]
Trap streets are often nonexistent streets, but sometimes, rather than actually depicting a street where none exists, a map will misrepresent the nature of a street in a fashion that can still be used to detect copyright violators but is less likely to interfere with navigation. For instance, a map might add nonexistent bends to a street, or depict a major street as a narrow lane, without changing its location or its connections to other streets, or the trap street might be placed in an obscure location of a map that is unlikely to be referenced.
Trap streets are rarely acknowledged by publishers. One exception is a popular driver's atlas for the city of Athens, Greece, which has a warning inside its front cover that potential copyright violators should beware of trap streets.[2]