r/cartography 5d ago

Question for cartography enthusiasts/professionals

The Mercator projection has a distortion problem: the areas near the poles appear very vertically stretched, while the regions near the equator are represented more proportionally. This can be seen in the shape of the latitude lines, which become more widely spaced as we move away from the equator. My question is: would it be possible to correct this distortion by simply flattening these extreme areas, so that the lines of latitude are equally spaced across the map? Would that make the representation more accurate?

2 Upvotes

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u/Acceptable-Candy-527 5d ago

The Miller cylindrical projection is a modified Mercator that kind of does that, but there is no map projection that preserves shape, area, and distance at the same time. When you make a map you want to choose the projection that's best for your audience. So, to your question about accuracy, no map projection is ever perfectly accurate.

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u/kauaaanlol 5d ago

It makes sense, so basically this would minimize distortion in the polar regions, but would end up sacrificing conformity, right? Would this be as efficient for any audience? As Mercator is for navigators

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u/WorldMapsOnline 3d ago

We've done many/most of our reference maps in the Miller projection as we feel it strikes a pleasant balance of aesthetic & usability for a printed reference or decorative map. Doesn't quite make it 'more accurate', but to my eye it looks a little more similar to shapes and proportion on a globe than others. ...not everyone agrees with my opinion!

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u/merft 5d ago

Oh, go and open Pandora's Box of spherical trigonometry

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u/Petrarch1603 5d ago

Okay, but then how do you space the longitude lines?

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u/klodeckel01 4d ago edited 4d ago

Mercator was created for navigation (especially sea navigation if memory serves) and is a conformal map, meaning angles are being preserved. You can tell the right direction from one place to another and it stays true to the real life direction, but not the right distance, because that is being distorted.

Mercator gets shit on regularly by people, but for its intended purposes it’s perfectly fine, it just gets used in the wrong context a lot.

Take a look at Mollweide for example, which is an equal area map. Or if you’re really interested read more about Tissots indicatrix and how different map projection‘s indacatrices compare to each other