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I have a world map shapefile and I can only seem to get two results, both of which are half right.

The first, using a projection like EPSG:3857, I get a map that doesn't cut the east tip of Russia off, but does include a weird bar streaming across the whole earth:

enter image description here

On another projection, I get this, but with the Russia getting cut up problem (which I think looks a bit odd):

enter image description here

This seems to replicate no matter what Shapefile I use, so I'm guessing it's the projection?

PolyGeo
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Joshua Boyd
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  • not sure, but your shapefile's geometries could be wrong. What is the source ? try EPSG:4326 which is another worldwilde projection mostly used. – Hugo Roussaffa Sep 22 '17 at 14:02
  • Unforunately that proejction isn't working either. I've tried about 4 four different mapfiles. From Carto, this one: https://www.arcgis.com/home/item.html?id=7a8585998b7f470b85235dcdb560c7e2, one from here http://thematicmapping.org/downloads/world_borders.php, and another from here: http://www.gadm.org/version2 – Joshua Boyd Sep 22 '17 at 14:26
  • Your second example appears correct. The 'cut line' is at 180 degrees and the map is centred on 0 degrees – firefly-orange Sep 22 '17 at 14:48
  • the reason for this is that some polygons cross the antimeridian and wrap around. see this answer for a fix. – Steven Kay Sep 22 '17 at 14:56

1 Answers1

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there are two problems. Firstly (your first picture) the datasource (from this website esri) has some bad geometries some bad geometries

Secondly, some projections decided to draw from long -180°W to 180°E. so that's why russia is cut. It could be a result of a geopolitic conflict, but I really don"t know why they chose this line. If you need to get Russia "United" on a worldwide map, you can use Polar projection , but forget the south...

from polar projection

Project the earth is a set of compromises.

Some cartographers used a trick as you can see on this picture
the tricks enter image description here
(here earth has more than 360° ...)

Hugo Roussaffa
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