title: R maps package missing counties
body: <p>I am attempting to make a heat map / choropleth / thematic plot of the USA by county using the R "maps" package.  Unfortunately some counties seem to be missing from the database.</p>
  
  <pre><code>library(maps)
  data(county.fips)
  which(county.fips[,1] == 35006)
  which(county.fips[,2] == 'new mexico,cibola')
  </code></pre>
  
  <p>results in no entries found</p>
  
  <pre><code>&gt; library(maps)
  &gt; data(county.fips)
  &gt; which(county.fips[,1] == 35006)
  integer(0)
  &gt; which(county.fips[,2] == 'new mexico,cibola')
  integer(0)
  </code></pre>
  
  <p>I know that this fips code exists!  (http://en.wikipedia.org/wiki/Cibola_County,_New_Mexico 
  <a href="http://en.wikipedia.org/wiki/List_of_counties_in_New_Mexico" rel="nofollow">http://en.wikipedia.org/wiki/List_of_counties_in_New_Mexico</a> )</p>
  
  <p>Anyone know how I can make my full plot?  All I could find on this was listed here: <a href="http://grokbase.com/t/r/r-sig-geo/0964515wmd/missing-county-in-maps" rel="nofollow">http://grokbase.com/t/r/r-sig-geo/0964515wmd/missing-county-in-maps</a></p>
  
  <p>Thanks for your help!!</p>