title: gnuplot - eps with a large number of points
body: <p>I have a datafile with many columns, data are not arranged in a grid, and would like to plot heat maps.
  My problem is that the number of points is very large, and since there is no structures grid, I do not know how to treat it without producing humongous files.</p>
  <p>I unsuccessfully tried to turn it into a grid via <code>dgrid3d</code> and then <code>splot</code> it, or to <code>p ... with image</code> it, while plotting it into a png picture poses me the problem of consistently set the size of the picture, as well as the scale of the font, with the rest of the document.</p>
  <p>How do you usually solve this problem?</p>