title: How to overlay global map on filled contour in R language
body: <p>I would like to plot some lat-lon data in a filled contour, and then overlay a map of the globe on top.  I am trying something like this:</p>
  
  <pre><code>filled.contour(lons, lats, glb.data,
  plot.axes={axis(1);axis(2);map(projection='rectangular',parameters=0,add=T)}
  )
  </code></pre>
  
  <p>The contour is plotted fine, and the map shows up, but only as a very tiny little black rectangle in a small area of the contour plot.  Of course, I want the map to stretch over the entire area of the filled contour plot.  </p>
  
  <p>I've also tried something like:</p>
  
  <pre><code>filled.contour(lons, lats, glb.data,
  plot.axes={axis(1);axis(2);map(projection='rectangular',x=lons,y=lats,parameters=0,add=T)}
  )
  </code></pre>
  
  <p>In this case, the map does not plot at all and I get an error message "nothing to draw: all regions out of bounds"
  People apparently do this successfully all the time, but I haven't been able to get it to work.  Can anyone tell me what I am doing wrong?  BTW, I don't want to use the lattice package.  It will not work with the other stuff my group is doing.  Thanks.</p>