   Create contour map
  hello all , i've implemented the marching squares algorithm in order to produce a single contour line from a heightmap (in a form of a CSV file containing height grid).what i want to do is create a contour map (topographic map) this brought up two problems:1. When i produce several contour lines (with a constant height difference) the lines might intersect.how can i solve this problem?2. I want to fill the contours with color. (and i don't really know where i start looking in order to do that)3. I must add , the reason i'm doing it myself is that i couldn't find any decent implementation with source code for this task , if anybody knows where i can find one i would appreciate it.thanks in advance , yoserian   