[R] Projecting data on a world map using long/lat

Michael Sumner mdsumner at gmail.com
Fri Dec 10 14:01:38 CET 2010

Oh, whoops I was looking for the "vote up" button and accidentally hit
"Reply All".

On Fri, Dec 10, 2010 at 8:25 PM, Barry Rowlingson
<b.rowlingson at lancaster.ac.uk> wrote:
> On Fri, Dec 10, 2010 at 2:21 AM, mathijsdevaan <mathijsdevaan at gmail.com> wrote:
>> Hi,
>> I have a dataset (CSV) with some counts of firms located around the globe.
>> Each count is assigned to the longitude and latitude of the specific
>> location. Now I want to plot these counts on a world map using dots (size of
>> dots represent the count). I have been unable to find any info on whether
>> this is possible and if so, how? Can you please help me? Thanks!
>  Plotting points is trivial - plot(data$x,data$y,pch=19,cex=data$size)
> will do for a start. i'm guessing your real problem is when you say
> 'on a world map'.
>  How detailed a world map do you need? There's an outline one in the
> 'maps' package, or you should be able to find a shapefile of the world
> on the web somewhere and use that via the rgdal package.
>  Other options include making a KML file of your points and overlaying
> on google earth. Or getting google map tiles and overlaying on
> that.... Or exporting your data to a GIS format and doing the pretty
> map in something like Quantum GIS. What are you trying to do exactly?
> also, you might want to post to r-sig-geo
> Barry
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Michael Sumner
Institute for Marine and Antarctic Studies, University of Tasmania
Hobart, Australia
e-mail: mdsumner at gmail.com

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