Why does windy.com use Mercator projection?

  • Mercator projection is incorrect! There are several more modern map projections that are more proportionate! I suggest you change that!

    [https://www.washingtonpost.com/news/worldviews/wp/2015/08/18/this-interactive-map-shows-how-wrong-other-maps-are](link url)

  • Hello Rafael,

    in fact, every map projection is incorrect. That comes with the projection & interpolation of things. The closest thing that shows earth very similar how it is, is a globe.
    The map used in windy is great for navigation.

    Best Regards

  • Mercartor projection has huge projection errors! For example, Greenland is almost twice the size of Africa, and it portrays countries in the northern hemisphere larger than those in the southern hemisphere, which is totally wrong! North America is almost twice the size of South America! Brazil, for example, is about the same size as the United States, and Australia about the same size as the whole of Europe. This map is controversial, and in many places is considered a biased map. It would be nice if it were modified for more modern projections such as google uses!

  • Sailor Moderator

    As said @BW_controlroom all map projection are wrong. You must make compromises when you project a spherical surface (the globe) on a flat surface (map).
    The Mercator projection is perfect for navigation, not for geographic application.
    The true Mercator projection does not show countries of northern hemisphere larger than those in the southern hemisphere. At same latitude north or south the surface deformation is the same.

  • Hello Rafael,
    actually when you type into google "google maps projection" it always says, that they are using mercator or some hybrid based on mercator, until you "going into space". Good looks does not mean automatically that it is handy. I worked before for a map printing company and other world projections that are on paper or screen oval, bringing in the problem of filling "holes" in the corner. So if you are solving this problem that exists since maps/projections are existing you are going to be a rich man.

    BTW (state of google on the 15.09.2019):
    google maps (desktop) starts you usually in mercator and switches then to "globe" mode if you zoom out. I guess they "cheat" with mercator because the want to save bandwith & computing power. This is why monstrosities like google earth (and pro) existed, this programs/apps are for pro users.
    google maps (mobile)still ueses some kind of mercator projection.

  • Sailor Moderator


    Hi @BW_controlroom
    Good explanation !
    Just to illustrate what you mean, Antarctica is not shown with a correct surface on Google map.


  • @BW_controlroom
    You are right, Google (as several web map providers do) uses the
    "WGS 84 / Pseudo-Mercator" projection.
    It uses the Mercator "spherical" formulas, that is, formulas written to project a SPHERE, for projecting the WGS84 ELLIPSOID. This is done for saving calculation time and resources.
    In other words, the Google Maps projection is an adaptation of the Mercator projection, with some little error more than the original.
    If you go to http://www.epsg-registry.org/ , and paste
    WGS 84 / Pseudo-Mercator
    in the search field, you find a rigorous description of that coordinate system.

  • Banned

    This post is deleted!

  • Hello, I think that the user should be able to select his favourite projection.
    I personally prefer the orthographic one when browsing maps. Have a look at how they implemented the feature at earth.nullschool.net. Very straightforward to switch between different projections.
    This is the main missing feature to Windy in my opinion, which is a fantastic tool overall.

  • Such a pity we can't have a look at the atmospheric circulation at the poles. Polar vortices and the like. Is it that difficult to number crunch a projection from a spherical data base? I have several apps that map the moon, Mars and Venus and old Geert de Kremer's projection doesn't get a look in. Oh well at least I can draw rhumb lines on the screen with a crayon 🤣

  • @rafaelntsilva I was looking up this same question when I noticed a large gale like swirl near Greenland and it wasn't clear on how large the storm was because the projection is so skewed. Since the operators of windy.com are too obstinate to properly answer your post (ie. "All map projections are wrong") There is an alternative that uses a spherical projection. It's at earth.nullschool.net. However they do not provide as much telemetry as windy.com does.

    @BW_controlroom. "All map projections are wrong" is not an answer to rafael's concern, it is an evasion. Even if all projections are wrong it doesn't mean you should use one of the least accurate known projections. It doesn't mean you cannot provide more accurate ones. It doesn't explain why the "3D projection" disappeared. Please take these concerns as legitimate feedback and consider incorporating alternative projections that represent scale more accurately.

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