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I'm trying to re-arrange countries using QGIS and Google Earth to get an idea of what the world would look like with a different arrangement.

I have a dataset in QGIS which gives me the 250-odd countries and their borders. When I take a single feature and turn it into a KML/KMZ file and open it in Google Earth this seems to work fine and the size is perfect. When I rotate this feature before exporting however it ends up becoming huge.

The country I am currently working on is Russia. When exporting the KMZ of Russia to Google Earth it overlays Russia perfectly. When turning it on its side before exporting it Russia becomes large enough to span the globe.

I think my original Russia feature file was a KMZ and my rotated one is a KML, if that matters.

Could this be related to projection? I'm a newb at GIS and the world map dataset appears in the Mercator projection. Would rotating within the Mercator projection like that throw everything off?

Ultimate question is how do I avoid it losing its scale while still rotating the countries.

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  • Web Mercator is a particularly useless projection for this task, since the poles are infinitely far from the Equator, and Russia spans ~170 degrees of longitude (and does in fact span the globe if you consider that eastern Siberia is in the far west of the Western Hemisphere).
    – Vince
    May 10, 2022 at 17:00
  • Will that have an impact if im rotating a feature in QGIS?
    – Harzard
    May 10, 2022 at 17:19
  • Have a look here: thetruesize.com
    – Babel
    May 12, 2022 at 20:06
  • Thanks, i've seen this and it is exactly what i'm after, but re-arranged in terms of direction etc. and around 50 countries at a time. Frustrating difficult to do this with any amount of ease!
    – Harzard
    May 13, 2022 at 22:28
  • This might work to be fair, would be great to be able to project onto a sphere
    – Harzard
    May 13, 2022 at 22:38

1 Answer 1

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You need to use an euler rotation to correctly rotate a country as a "rigid body on a sphere" - this is just like plate tectonics, except applied to a country's borders. The process is identical. But it is only possible with a correctly formulated code. You would probably define a "pole" about which the rotation takes place, which is like an axle running from a point on earth's surface, to its centre, and to which all points on the country's borders are "rigidly" bound - that means there is no relative motion between points on the border (or inside it). If you "turn" the axle in one direction or the other (like an axle it revolves around itself) then the rigidly attached "country" will move with it, and will always move across the surface of a sphere. You can then move the country a certain angular distance in a direction determined by your choice of pole and the sense of rotation about it, and this will give you the new coordinates of your country's borders after such a rotation.

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