title: Heatmap R: how to remove dashed lines
body: <p>I'm new to heatmap. I've data which looks like:</p>
  
  <pre><code>Dat       A        B        C        D        E
  A    100       30.3      0       55.71    45.78
  B     12.85   100       72.85    12.64    98.51
  C      0       27.85   100       82.28     3.07
  D     23.71    30.64    40.28   100        6.33
  E     25.25    85       52.36    36.33   100
  </code></pre>
  
  <p>R code:</p>
  
  <pre><code>pdf("hh.pdf")
  library(gplots)
  data = read.table("file.txt", header=T, row.names=1)
  heatmap.2(as.matrix(data))
  dev.off()
  </code></pre>
  
  <p>When I plot heatmap with above data, it is Okay, with those grid lines. But when I get row count as 100 or in that range, plot is barely visible. Plot is covered with dash-dash vertical lines.<br>
  I want to get rid of those annoying lines. 
  I've saved in <code>.png</code> format, but again, I get same lines.</p>
  
  <p>I have checked <a href="https://stackoverflow.com/questions/14305448/heatmap-2-gplots-package-how-to-remove-annoying-lines-in-some-cells">heatmap.2 (gplots package) - how to remove annoying lines in some cells?</a></p>
  
  <p>Using <code>R 3.0.2</code> </p>