title: get the pixel count between two points in a bitmap
body: <p>I am beginner in C#.NET .I am on a project to process approach maps.this map contains the surrounding area of a runway,where the flight can fly in order to land.
  this map is a bitmap image.it contains longitudes and latitudes on the borders of the image!</p>
  
  <p>now the aim of the project is to get the geological coordinates(lats/long) of points on the map,(when clicked or hovered on that point by mouse,) based on the given geological coordinates on the border of the map.so if we give the input for a point with its lats/long coordinates the other points on the map can be interpolated.</p>
  
  <p>suppose there be X pixels between any two longitudes and Y pixels between any two latitudes.if we set a reference point ,then depending on the distance(number of pixels from the reference point in x and y direction individually) of the pixel that is being hovered or clicked by mouse pointer we can get the lats/longitudes of that point in a small window(may be like tool tip or pop up).</p>
  
  <p>the math surrounding the interpolation can be:</p>
  
  <p>new lat=  ref lat +  [ref lat(only minutes)/Y] *(vertical distance between reference point and new point in pixels)   </p>
  
  <p>new long=  ref long -  [ref long(only minutes)/X] *(horizontal distance between reference point and new point in pixels).</p>
  
  <p>there is a point called mid point on the centre of the run way(at the centre of the graph).i also need to find the angle made by line joining midpoint and new point(where the mouse hovers or clicks) with the verticle of the map.</p>
  
  <p>so any one please give me ideas how to start the project and what are things (tool bar controls,methods) i require to build the gui containing picture window and pop up window(containing information about that point or pixel) where ever i click the mouse .thanks in advance.</p>