title: Plotting Great Circle Paths
body: <p>I'm trying to plot some path/connection based maps but am unable to figure out how.</p>
  
  <p>I see a lot of possibilities for one point based metrics (crime hotspots in London, etc. with googleVis, ggmap, etc.) but I can't find too many examples of two points based metrics (immigrations between cities, train routes, etc.) There is an example with the package <a href="http://flowingdata.com/2011/05/11/how-to-map-connections-with-great-circles/" rel="nofollow"><code>geosphere</code></a>, but it seems to not be available for <code>R 3.0.2</code>.</p>
  
  <p>Ideally I would like something like this <a href="http://mbostock.github.io/d3/talk/20111116/airports.html" rel="nofollow">D3 example</a> and would also like to customise the thickness, colour, etc. of the lines and the circles.</p>
  
  <p>PS: I don't suppose <code>rCharts</code> can do this just yet, right?</p>