I tried to reproduce a recent question on spatial data visualization using ggplot2 and received the following error message during fortify(world, region = "ISO3"):

Error: TopologyException: Input geom 0 is invalid: Self-intersection at or near point 
3980740.7660219339 4277735.2740812832 at 3980740.7660219339 4277735.2740812832

Any ideas on that?

1 Answer 1


As per my comment in that question, it's to do with the spTransform. Simply remove the offending line:

world <- spTransform(world, CRS("+proj=robin"))
  • So it's simply the projection that is not suited for world-wide data?
    – fdetsch
    May 10, 2015 at 7:33
  • 1
    As far as I can tell it's the Robinson projection which is suitable for mapping the world: en.wikipedia.org/wiki/Robinson_projection I suspect transforming the polygons is causing overlap
    – Phil
    May 10, 2015 at 8:18

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