How can I cover up areas of a plot?

Basically I'm plotting contours on a grid, but I want to cover part of the plot area up.

The contours are defined on a grid with x and y vectors:

contour(x,y,C)

I want to be able to cover sections of the plot with a filled area determined by whether a grid point is included in the area or not. So for example, for the given points on an 8x6 grid:

mask = [1 1 1 1 0 0 0 0
        1 1 1 1 0 0 1 1
        0 0 0 0 0 0 1 1
        0 0 0 0 1 0 0 0
        0 0 0 1 1 0 0 0
        0 0 0 0 0 0 0 0];

I want to superimpose my contour plot with a rectangle, a square, and a triangle, at the corresponding positions in the grid. Does anybody have any idea how to go about doing this? I'm at a complete loss. I still need the underlying contour plot to be visible at those points marked '0', I just want to fill in the squares/triangles on the grid bounded by '1's.

I can plot the points that bound the areas just with

plot(x,meshgrid(x,y).*mask)

but I want to fill in the areas in between, not just have points.

Answer 1

[Image Analyst]

Try patch() or fill().

[John]

Hi,

I had a look in the help but I'm really not sure how I'd go about converting the mask I have into something useful for either of those functions. Could be you a bit more specific?

[Image Analyst]

Well you have to get the vertex coordinates. Alternatively you could follow Steve's suggestion: http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/