Many documentaries seem to agree that the world map we currently use is far from accurate, and it’s misrepresenting the size (and even shape) of many continents, islands and countries. It’s using an outdated projection technique called ” Mercator projection ” that was mainly used for sailing back in the 16th century. Why aren’t we using a map that’s more up to date? Can maps like “thetruesize” website be relied upon?
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All flat maps of earth will have distortion, Different projection have different problem but all have some. The only way to have no distorsion is a globe.
Mercator projection do preserve local shape and angles but is quite bad with area
Projection with the correct are like the on https://en.wikipedia.org/wiki/Equal-area_map are still disorsion, the have just chagne what is distored
You can for example use https://en.wikipedia.org/wiki/Gall%E2%80%93Peters_projection#/media/File:Gall%E2%80%93Peters_projection_SW.jpg that have the correct area. But there is still a problem.
Look at Africa, a line straight noeth from the most southern point is 7230km long. A line from most eastern tips to the same latitude on the western side is 7340km. So practical the same distance.
But on the map above it was 438 pixels north to south but only 245 east to west. So what should be 1:1 is 1.75:1
So the map distor shape but the area is correct, all flat maps do. If you like no distosion you need a sphere so use for ecample https://earth.google.com/web/
Mercator is unique in representing north as up and south as down everywhere while preserving local directions and shapes. This is very useful for navigation, which is what maps are primarily used for. People generally don’t care that much about the size of different places, so it’s ok that it gets distorted.
Drag things around on thetruesize and watch them bend and warp. The size may be correct, but the shape is now wrong. Which is better, really depends on your purpose.
A good way to imagine (or actually attempt) what everyone is saying here is to picture an orange with the earth drawn on it. Find a way to peel the orange and make it where you can press it flat on a table and still look exactly the same.
This is a problem with trying to draw a three-dimensional shape on a two-dimensonal surface. It’s impossible to do this without some level of distortion, because you’re changing the shape of the underlying structure on which the object you’re drawing is located. However, by working with the shape of the drawing it’s sometimes possible to control how the distortion happens, and to what degree.
The Mercator projection was never intended to be used as a map. Its intent was to be used as a navigation chart, just as the documentaries you’ve been watching say. Its distortions are controlled with that goal in mind: it doesn’t distort shapes, but sacrifices pretty much everything else in order to achieve that. The end result is that a straight line on a Mercator map is equivalent to walking in what’s called a *great circle* on a globe, which we would tend to (sonewhat mistakenly) call a “straight line” too: pick a direction, walk in that direction, and never turn left or right. You can see how that would be useful for sailors, aviators, or pretty much anyone else needing to navigate: to see what you can expect to counter on a direct route between two points, just draw a straight line.
But that projection, like all projections, makes sacrifices. In Mercator’s case, objects far from the equator get blown up to larger sizes. The most egregious example is Antarctica, which looks absolutely massive on Mercator maps, but North America and Asia both get blown up pretty severely, as do Europe and Australia to a somewhat lesser degree. Meanwhile, places largely located close to the Equator -Africa and Central America in particular- seem much smaller by comparison.
Why keep using it? Other so-called “[conformal projections](https://en.wikipedia.org/wiki/Conformal_map_projection)” do exist, with different degrees of deformation in different places, but Mercator appears to be the only one that fills a rectangle, making it more or less ideal for filling a piece of paper or a computer screen. Especially over small areas that don’t show multiple continents anyway, Mercator gets the job done, so it still sees use in these fields.
But all this just covers navigation. Maps can be used for many other purposes, and Mercator was only ever devised to be used for one. Other projections exist, optimizing for other things. Arguably the most famous today is [Gall-Peters](https://en.wikipedia.org/wiki/Gall%E2%80%93Peters_projection), which attempts to preserve the relative areas of land masses at the expense of shapes. In an age where it’s often common to display graphs of information using a map to show relevant areas, this projection’s equal-area property can be useful as a means to bring the sizes of these landmasses into the graph as information in its own right. The distortions in shape make it less useful for navigation, but nobody tries to navigate using only a chart intended to show the relative wealth or populations of countries, so the loss of navigation ability doesn’t really matter for those sorts of maps.
But ultimately, if you want to completely avoid deforming areas or shapes, the solution isn’t a map at all: it’s a globe. The only way to avoid the problems with projecting a round image onto a flat object is to avoid projecting it in that way at all. But globes bring with them their own problems relating to handling and storage, so maps are here to stay, and with them, arguments over what projection to use.
If you want to look into some of these projections and their problems yourself, I recommend looking into [Tissot’s indicatrix](https://en.wikipedia.org/wiki/Tissot%27s_indicatrix). It’s useful for visualizing how the distortions in map projections work at a glance.
We use a lot of different maps for a lot of different reasons. Making a flat map is always a case of balancing different kinds of distortion against each other. The Mercator projection distorts size, but it preserves direction which is useful for navigation. Other projections have different priorities, for example preserving relative size, shape, orientation, and direction.
We don’t, really. If you go to Google Maps and hover over the layers, you can select “globe view” and you’re shown an accurate projection on a globe (zoom out to see it).
We used to have to go with a flat projection because we had to put maps on paper, but now that we have digital maps there’s no particular reason to do that if you don’t benefit from that particular projection in the moment.
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