c# - OxyPlot Contour Series -

i want make contour plot live x-y coordinate data (using oxyplot).

i've seen example given using contourseries, , i'm having trouble understanding how achieve contours.

here example code:

namespace examplelibrary { using system;  using oxyplot; using oxyplot.axes; using oxyplot.series;  [examples("contourseries"), tags("series")] public class contourseriesexamples {     private static func<double, double, double> peaks = (x, y) =>            3 * (1 - x) * (1 - x) * math.exp(-(x * x) - (y + 1) * (y + 1))            - 10 * (x / 5 - x * x * x - y * y * y * y * y) * math.exp(-x * x - y * y)            - 1.0 / 3 * math.exp(-(x + 1) * (x + 1) - y * y);      [example("peaks")]     public static plotmodel peaks()     {         var model = new plotmodel { title = "peaks" };         var cs = new contourseries             {                 columncoordinates = arraybuilder.createvector(-3, 3, 0.05),                 rowcoordinates = arraybuilder.createvector(-3.1, 3.1, 0.05)             };         cs.data = arraybuilder.evaluate(peaks, cs.columncoordinates, cs.rowcoordinates);         model.subtitle = cs.data.getlength(0) + "×" + cs.data.getlength(1);         model.series.add(cs);         return model;     } } 

some of things don't understand 'peaks' math equation (what's purpose, how derived?) , other thing don't understand how contour derived.

to understand "peaks", need familiar general delegate func<t, tresult>. in example, generate delegate "peaks" has 2 double inputs, , 1 output result double also. inputs assumingly x , y. output function after lambda "=>".

regarding second question; how contour derived? can imagine contours 3d object drawn on plain xy cartesian, @ each x,y there value of z on same plain.