circle in pcolor map with radius as half of map length

Hello, I want to plot pcolor

pcolor(X)

X=50 * 50 matrix

I wish to plot a circle within pcolor map; with centre as centre of circle; and radius as half of pcolor map.

I hope I am clear. Please help.

[Jan]

What exactly is "half ov pcolor map"? Do you want to draw the pcolor and first an than a circle on top of it? Or do you want the pixels of a circle in a 50x50 raster?

[Bhowmik.U]

I want to draw pcolor first and then a circle on top of it to mask (cover) region outside the circle.

[Jan]

So you actually want to get a binary mask with an excluded disk, no a "circle". The less the readers have to guess, the easier and more likely is a useful answer.

[Star Strider]

I am not certain what result you want.

If you define your pcolor plot in terms of a radius and an angle (rather than x and y), you can then use the pol2cart function to create a circle plot from it. For an example, see Applying shading radially outwards on a circle (link).

[Bhowmik.U]

I am enclosing the diagrammatic representation of my querry....I wish to eliminate the gray part from pcolor plot.

Answer 1

[Walter Roberson]

temp = -24.5:1:24.5;
mask = temp.^2 .' + temp.^2 > 24.5.^2;
Xt = X;
Xt(mask) = nan;
pcolor(Xt);

[Walter Roberson]

temp = -24.5:1:24.5;
mask = temp.^2 .' + temp.^2 <= 24.5.^2;
pcolor(X)
hold on
pcolor(mask)