How do I make a pcolor plot use the first row and column of the data for the X and Y axes?

I need to do an interactive image plot of data that are in matrix form. The first row and column are the X and Y values, the rest of the matrix represents the corresponding Z values. A pcolor plot plots all the data in the matrix. How do I make it use the first row and column for the X and Y axes?

Answer 1

[Sean de Wolski]

If I understand you correctly, you need to extract the first row/column and use meshgrid to build the grid for surf (better than pcolor in my opinion).

x = [nan, 1 2 5 10;
  cumprod(1:4).',magic(4)]

[xx,yy] = meshgrid(x(1,2:end),x(2:end,1));
surf(xx,yy,x(2:end,2:end));
view(2)

x looks like this

nan x_index
yindex data

Answer 2

[Image Analyst]

This is false: "A pcolor plot plots all the data in the matrix." Just try it

myMatrix = magic(4); % Make 4x4 array
pcolor(myMatrix); % Displays 3x3 image.

If I were you I'd use imshow() instead, or image() or imagesc().

[Chad Greene]

I made an example file for this and posted it on FEX.