![]() Huh? Say it again? How can these distortions be allowed? I wouldn’t get on a plane shaped like that. And there’s Mercator in the bottom right. ![]() Here’s page 27 from my Cartography book (you’ve got a copy already right?) which shows how a common shape is modified through re-projection. If you want to compare the Norwegian capital city of Oslo, at 59.9139° N with Singapore, at 1.3521°N you’ll find that Oslo appears 75% larger than Singapore at the same map scale. It’s also pretty much useless if you want to compare things across a map, and the smaller the map’s scale the bigger the problem. Australia is 2.97 million mi² and has a population of 24.6 million. It’s 75,767 mi² in size and has a population of 146. For instance, on a world map, Ellesmere Island in the Canadian arctic is shown approximately the same size as Australia. But for small scale maps it is virtually useless. So, Web Mercator is quite serviceable, particularly for large scale maps, or for regional mapping. This creates an attractive consistency from a software engineering perspective and avoids some of the confusion that sometimes comes with other projections. At large scales, conformality means square buildings remain square. Wherever you are on the map, up is due north, down is due south and west and east are always left and right. The reason Web Mercator was suitable as the basis for early web mapping is that it creates a convenient square shape for the entire world if it is truncated at approximately 85° North and South of the Equator. Conformality meant that shapes were maintained and distortion was relatively low at large scales when zoomed in. Web Mercator became the default web map tiling scheme for good reason – it was relatively simple to build a seamless, zoomable web map. And, of course, the huge revolution in mapping that the internet has supported has done its fair share to further embed the Mercator projection into our daily psyche. ![]() ![]() They become challenged by seeing the world presented using other projections. In 1943, the New York Times stated that, “We cannot forever mislead children and even college students with grossly inaccurate pictures of the world.” So why is it so often used? Well, if you use the projection often enough people will believe it to be the de facto view of the world. Yet despite this weird view of the world, presented almost as a square, curiously it has become the view of the world we often see on school walls, in news media, and web maps.ĭebate over its utility is nothing new. One consequence of the projection is that it grotesquely exaggerates northern and southern latitudes, warping the size of places relative to one another. He didn’t make the map projection for any other purpose. Mercator made the map for navigation, and the underlying projection supported that purpose perfectly. The map was titled “Nova et aucta orbis terrae description ad usum navigantium emendate et accomodata” which translates as “new and improved description of the world amended and intended for the use of navigators”. ![]()
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