Problem with PlotRange as an option to ContourPlot

Questions
1

Please help me solve a “clipping” issue arising in a Plot I am working on.

Compare these two commands: Definition for the surface surf is at the end on the post.

ContourPlot[surf[y, x], {x, 0, 1024}, {y, 0, 256},
 ColorFunction -> "DarkRainbow",
 PlotRange -> All]

ContourPlot[surf[y, x], {x, 0, 1024}, {y, 0, 256},
 ColorFunction -> "DarkRainbow",
 PlotRange -> {{0, 1024}, {0, 256}}]

90302plots.png
90302plots.png1094×556 45.5 KB

The first one looks fine, you can see all the contours.

But for the second one, some of the contours disappear and the colors turn to white at the center of the plot.

Beside that, plot #1 is not Framed, whereas plot #2 is.

Why is that?

Definition for surf:

A = 800000;
a = 80;
b = 0.0007;
surf = Function[{x, y}, 
  A (Exp[-b (x - 90)^2] + Exp[-b (x - 90 - 70)^2])/((y - 512)^2 + a^2) ]
2

For ContourPlot, PlotRange has a 3rd argument for the “height” of the contour plot. Try

PlotRange -> {{0, 1024}, {0, 256}, All}

The default is

{Full, Full, Automatic}
3

Perfect! I should have thought about it myself.

Thanks a lot.