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Here's my problem. I want to compare the area within multiple polygons in different parts of the world. I have the longitude and latitudes for each point of each polygon. My problem is that I don't know what projection to use to get x-y coordinates from the long-lat coordinates. I know OpenStreetMap has the projectMercator() function, but areas are known to inflate quite badly with latitude. (http://en.wikipedia.org/wiki/List_of_map_projections)

--> Do you guys know of an R function like projectMercator, that doesn't have such a distortion? I've been going over different types of projections in Wikipedia, but it's very unclear to me which is best for area comparisons, and then if those projections exist in R as functions (if they don't I'm fine hand coding them, though!)

Thanks!!!

  • Hillary
Hillary Sanders
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  • Not sure if this is much help but have you tried ``spTransform`` from the ``rgdal`` package? – Mike.Gahan May 15 '14 at 17:54
  • I think this link maybe useful to you http://stackoverflow.com/questions/18639967/converting-latitude-and-longitude-points-to-utm – Mike.Gahan May 15 '14 at 17:56
  • Thanks @Mike, I ended up using something super similar from the rgeos() package; I used Robinson's projection which Wikipedia says is significantly better distortion wise (but still not perfect). I'll check out what these guys have done too though. – Hillary Sanders May 15 '14 at 21:01

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