be added to future Tube maps in late 2010, and, as of May 2013, it is up and running. Underground lines on geographically-accurate maps Like many other rapid transit maps, because the Tube map ignores geography, it may not accurately depict the relative orientation and distance between stations. Transport for London formerly published several bus maps that depicted the approximate paths of tube routes relative to major streets and London bus routes. The maps also show locations of certain cultural attractions and geographic landmarks. Internet mapping services such as Google Maps offer a "Transit Layer" showing actual routes superimposed on the standard street map. A map shows underground, overground and DLR lines and National Rail stations within Zone 1–2. Spin-offs and imitations The 'look' of the London Underground map (including 45° angles, evenly-spaced 'stations' and some geographic distortion) has been emulated by many other underground railway systems around the world. While London Underground have been protective of their copyright they have also allowed their concepts to be shared with other transport operators (Amsterdam's GVB even pays tribute on its map). The success of the Tube map as a piece of information design has led to many imitations of its format. What is probably the earliest example is the Sydney Suburban and City Underground railway map of 1939. It follows Beck's styling cues, and in size, design and layout, it is nearly a clone of the London map of the late 1930s, right down to the use of the Underground roundel. In 2002, Transport for London launched a series of London Buses "spider diagrams" to display at bus stops around the city, conveying bus route information in a schematic style similar to Beck's design, with straight lines and 45° angles depicting geographically distorted bus routes, coloured lines and numbers to differentiate services, and graphical markers to show bus stops. Tube and rail lines are not included, but interchanges are denoted with appropriate symbols by bus stop names, such as the Tube roundel. Unlike the traditional Tube map, the bus maps display services appropriate to specific transport hubs rather than a full network. Each map also contains a central rectangle of a simple geographically accurate street map to display the positions of bus stops; outside the rectangle, the only geographic feature to appear on the bus maps is the River Thames. The maps are also available for electronic download, with map collections