title: What is the width of a pixel in Google Maps for given zoom level and view?
body: <p>I would like to know the height and width of a given pixel given the zoom level of a Google Map.</p>
  
  <p>I can see that different zoom levels affect the scale: <a href="http://maps.google.com/maps?q=10.0,0.0&amp;z=2" rel="nofollow">http://maps.google.com/maps?q=10.0,0.0&amp;z=2</a> and <a href="http://maps.google.com/maps?q=10.0,0.0&amp;z=3" rel="nofollow">http://maps.google.com/maps?q=10.0,0.0&amp;z=3</a> have different sized Niger, for example.</p>
  
  <p>Also, I can see that the latitude matters: On <a href="http://maps.google.com/maps?q=50.0,0.0&amp;z=3" rel="nofollow">http://maps.google.com/maps?q=50.0,0.0&amp;z=3</a>, Spain and Iceland appear to be the same width but Spain is actually about twice as wide.</p>
  
  <p>Map bounds seem not to matter because resizing the window or dragging the view around doesn't affect the size of countries.  (The scale legend is affected, however, but I don't care about it.)</p>
  
  <p>It seems that the answer should depend on some combination of zoom level and latitude of pixel in question.  It seems that both width and height are affected.  Longitude seems to have no effect.  An numerical solution would be best.</p>
  
  <p>(I want this so that I can pre-process a list of coordinates to remove coordinates that would appear in the same pixel.)</p>