Projection / Proportion / Compatibility?

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This topic contains 1 reply, has 2 voices, and was last updated by  Graham Asher 2 years, 7 months ago.

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  • #4883

    Liquidized
    Participant

    After reading good things about Natural Earth Data, I’ve downloaded it to try and work on some much belated map work but have run into something of which I can’t understand.

    I’ve loaded the various layers I want to use into Qgis and exported them for editing in Inkscape, I’ve then imported a few maps from the internet so I can use them as reference to add the extra bits I want.

    But that’s where the confusion hits.

    No matter what donor maps I use I can’t get them to match-up to Natural Earth map. Working with the USA if the donor map is aligned to the US’s southern coast the whole of northern US is miles to far up, and if I align it to the US’s north, the south is miles out. It seems as if the southern half of the US matches just fine but the northern half of the US is squashed down.

    Does Natural Earth use a specific projection or something that most maps don’t? Have I messed up somewhere? What I expected to be fairly simple is just making me feel like an idiot. I’ve attached a image to show what I’m talking about using a Google map as donor, just in case my ramblings aren’t terribly clear.

     

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    #4894

    Graham Asher
    Participant

    Natural Earth data is unprojected degrees of latitude and longitude using the WGS84 datum.

    Judging by your image, one map is projected using the Mercator projection while the other is probably projected using the (very bad) Plate Carrée projection, which converts lat/long in a linear fashion to y and x coordinates.

    I advise looking up those projections in Wikipedia.

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