how to specity axis using imagesc

Hi. I have a matrix A of size 200*40. I have to generate image for every 200 time steps for which i am using imagesc(A). By default matlab takes the x and y axis as the size of the matrix. But I want to force both the axis between 0 and 1. Any suggestions ?

Answer 1

[Honglei Chen]

You can just do

imagesc(linspace(0,1,40),linspace(0,1,200),A)

HTH

[Real User]

Thank you. Indeed: imagesc plots the matrix "in the matrix order".

That is, y-axis top-to-bottom = rows of A from 1 to 200, and x-axis left-to-right = columns of A from 1 to 40.

In particular, A(1) = top left, A(200) = bottom left, etc. Axis values have first x, then y (i.e., first "column values", then "row values"). Therefore, indeed, linspace(0,1,40) must be first, although it is a 200x40 matrix.

imagesc(xAxisValues,yAxisValues,reshape(B,nY,nX))

when B is to have nY rows (y-axis top-to-bottom in imagesc) and nX columns (x-axis). Otherwise, it is hard to remember that we have xAxisValues before yAxisValues but nY before nX.