title: Draw a Graph in C# using zedGraph
body: <p>I need to create a graph that have the following properties:<br>
  The X Axis is for schools names.<br>
  The Y Axis is for classes names.<br>
  In Point (x,y) I need to put a dot that it's color will represent the number of students (darker means more students).<br>
  I'm using ZedGraph (using that sample: <a href="http://zedgraph.org/wiki/index.php?title=Gradient-By-Value_Demo" rel="nofollow noreferrer">http://zedgraph.org/wiki/index.php?title=Gradient-By-Value_Demo</a>), but I don't know how to put the dot (and to determine it's dark-level) in the correct position (compare it to school's name and class's name).<br>
  Also, I don't know how to make the X and Y axis to show the school's name and the class's name.<br>
  How can I do that? (It's NOT have to be in zedGraph).<br>
  many thanks!</p>