title: Openlayers 3 - What does resolution represent as a style function parameter?
body: <p>I am trying to use resolution passed into the StyleFunction to work out the size of my image Icons.  Using tests, at a zoom where the scale line is 100m the resolution reported to the styling function is 2.3886.  </p>
  
  <p>I've take screenshots of the scale line and measured its length in pixels.  A 100m scaleline is 68 pixels, or 1.4705 metres per pixel.</p>
  
  <p>1.4705 !== 2.3886, so what is the resolution unit?  The API documentation does not explain it and says it is just a number, but without an idea of units it is difficult to work out.</p>
  
  <p>This is to accurately scale the icon to real world length BTW.</p>
  
  <p>Using this jsfiddle.net/dz9gL0g0/ I find that 200m scaleline reports the 2.38, but 100m returns less (1.19).  Is the resolution I'm getting from the previous zoomlevel?  If I use the resolution passed in OR call the getResolution function directly, 100m scaleline always returns 2.83 for me, not the 1.19 I think it should, although 1.19 * 84 is mostly correct (scale line is bigger in example than my app, which gives me a 68 pixel scale line for 100m).</p>
  
  <p>Moving the window alters the resolution - resize the jsfiddle and the resolution unit changes.  My 100m scaleline still fits the geographical feature I use to test, but now reports 2.38.</p>