Simple problem with plotting

I have a 4X40 matrix of intensity values 'mat' that I am plotting using figure;imagesc(mat). However, when I do plot this, the first is row is plotted on .5 on the y-axis. As a result, each row is represented in multiples of .5 instead of 1 on the y-axis. My y-axis spans from .5 to 4.5 which is incorrect - it should be 1 to 4. Please help.

Thank you!

Answer 1

[cocopuffs]

I changed my code to figure;imagesc(1,1,mat) to get the answer I was looking for

Answer 2

[Adam]

This is due to the fact that the centre of the first pixel is placed at 1, but it spans from 0.5 to 1.5, the second pixel from 1.5 to 2.5, etc because pixels have a width of 1.

If your axes started at 1 then your final pixel would start at 4 and actually finish at 5 so your range would be 1 to 5 on the axes.