title: access spatial objects in spatial polygons data frames
body: <p>In this thread ( <a href="https://stackoverflow.com/questions/5126745/gadm-maps-cross-country-comparision-graphics">GADM-Maps cross-country comparision graphics</a> ) Gavin Simpson helped me to merge multiple Maps from GADM to one object that can be plotted.</p>
  
  <p>But how can I now access one part of the spatial polygons data frame - for instance how could I change the color of one country?</p>
  
  <p>Additional question (I don't really need that now, but maybe I can learn something):
  Why does the solution I posted in the former thread only work with level 0? Is there a way to make it also work with other levels?</p>
  
  <p>[edit]<br>
  answers below show how to change colors.
  to access one of the rows int the spatial polygons data frame one can use</p>
  
  <pre><code>&gt; row.names(df)
  # outputs the accessable rows
  # e.g. [1] "ARG" "CHL"
  &gt; plot(df["ARG",])
  # plots just Argentina
  </code></pre>