The Automobile Association, on the other hand, was formed in 1905 with the decidedly anti-governmental intention of helping its members avoid police speed traps, which had been implemented following the Motor Car Act of 1903. Within a few years, it had put up thousands of directional road signs as well, and was the principal erector of such until local authorities took over in the 1930s. From 1910, it also produced maps to guide its members to the best routes, hostelries, and amenities along the newly motorized highways.

The map dispute arose when the Automobile Association was accused by the Ordnance Survey of tracing its careful surveys onto the association’s maps, thereby stealing its data, carefully collated from historical triangulations and aerial photography, from the work of surveyors on the ground and in the air. The process of assembling a map is costly and time-consuming, and its execution forms the prime value of any cartographic business; hence, theft of this nature is taken seriously.

The dispute—which had been rumbling on for some time, first surfacing in the courts in 1996 and dating back as far as 1990—ended when the Automobile Association agreed to pay twenty million pounds to the Ordnance Survey in a settlement agreed just hours before the case was due before a judge. Centrica, the multinational utility which acquired the Automobile Association in 2001, made a statement that “the AA ’s processes were not as robust as they should have been,” while stressing that they had “genuinely sought” to create their own maps from scratch.

The case rested on a series of unique fingerprints within the maps themselves described by the Ordnance Survey’s chief executive Vanessa Lawrence as “design elements in the way we show things which are not obvious to either the user or the copier. When we see the two versions side by side, we can spot clues.” The Guardian reported that these features were pure design elements such as the width of roads, and did not extend to putting misleading features into the maps themselves, corroborating what Lawrence had claimed: “There are some publishers who put deliberate mistakes in their maps. We don’t do that—it would mislead our customers. For us, it’s more about the style we use.”

Other map-makers are not so scrupulous. Anecdotally, many cartographers relate the stories of deliberate errors introduced into maps to prove their provenance, from kinks in rivers and the addition of small buildings to exaggerated curves in roads and the systematic alteration of minor digits in geographic coordinates; nothing that would put the user off-track, but enough to make a map’s actual origin certain. Most of the time, such tricks are indistinguishable from errata, but across enough sheets or data points they form a pattern, and organizations such as the Ordnance Survey employ teams of experts to ferret them out in their competitors’ products.

Such interventions are known colloquially as “trap streets,” a collective term for cartographic fictions with the intent to deter copyists. And, as noted, they may not all be streets: any geographic alteration can be used, from the fabrication of a remote nonexistent town to the mislabeling of the elevation of a mountain range. The existence of such doctored locations is routinely denied in public statements by publishers, even when acknowledged in closed legal proceedings, and so the Ordnance Survey’s denials should be viewed with a certain circumspection.

Open Street Map, whose intention is to create a copyright-free cartography of the world distinct from the proprietary versions that preceded it, is particularly susceptible to such intrusions unwittingly added by its contributors, and so takes pains to warn of the dangers of trap streets. Its copyright guidance references a number of such fictions, many of which have been removed after their exposure.

Moat Lane in Finchley, North London—a suburban street specified in the TeleAtlas directory, used as the basis for Google Maps. On Google’s map rendering, it carved, until it was recently removed, at right angles from the end of Clandon Gardens, turning plausibly parallel to the North Circular Road. In satellite view, however, Moat Lane flashed into falsity: Clandon Gardens is a cul-de-sac, and the fat white finger of Moat Lane overlaid trees, gardens, and a pitch-roofed house. It does not exist.

In the market town of Shrewsbury, Kerbela Street once took a hard right and extended right through the Shropshire Learners & Driving Instructor Training center, an unexpected gift for new drivers reliant on satellite navigation. A similar twist used to occur at the foot of Nether Craigour in Edinburgh, where Oxygen Street purportedly ran between two houses. The hairpinned Adolph-Menzel-Ring and Otto-Dix-Ring, real streets in the German town of Zeuthen, were at one time erroneously attached to Wiesenstrasse in a location that the satellite would reveal to be suburban woodlands. The A–Z Map of Bristol appends to the east side of the well-heeled Canynge Square another cul-de-sac, which does not appear in the index, or in reality. The name of this fictional addition? Lye Close. Someone at TeleAtlas has an intriguing sense of humor.

Not all errors on maps are intentional. “Paper streets” are the result of failed planning applications that have festered long enough to appear on speculative, proposed maps of city’s futures and have thus been incorporated into the official cartographies without ever making the leap to macadam. As such, they may appear on official city maps and land deeds, and even constitute legal rights of way, approved by courts and enforceable by them, and yet undriveable, unnavigable, unobtainable.