title: R color the map with contour
body: <p>I want to draw the sst(sea surface temperature) with R,but there is still with some error in the line ,as a new ,please tell me where the problem is </p>
  
  <p>the rr.txt is formated like this</p>
  
  <pre><code>  89 rows  180 cols means 2*2 grid data
  
  ee&lt;-read.table("C:\\Users\\topmad\\Desktop\\New folder\\rr.txt")
  ee
  dim(ee)
  long&lt;-seq(0,360,2)
  lati&lt;-seq(0,180,2)
  m&lt;-c(91:180, 1:90)
  m
  length(m)
  
  require(maps)
  maps::map(database="world", fill=TRUE, col="light blue")
  maps::map.axes()
  contour(long,lati,ee[,m], add=TRUE)
  par(ask=TRUE)
  </code></pre>