How color fill grid squares in plot?

I want to make a with color filled boxes instead of data points. Where instead of plotting specific points against time, the grid box/space is filled with that color for certain Y values. I know how to create the plot with gridlines but I'm not sure how to color-fill the grid squares (see other picture with red scribble for what I mean). Where the red scribble is, I want it completely filled with red. Any tips?

[Adam Danz]

See doc pages for pcolor and imagesc. Is this what you're looking for?

[Robert Daly]

A tip: Depending on your grid resolution, the first time you run pcolor it can come out all black with grid lines.

To see the colours you should use the following command after you run pcolor

shading flat

or

shading interp

Answer 1

[Star Strider]

The patch function would be appropriate here.

Perhaps something like this —

x = 0:5:20;
y = 0:7;

figure
patch([5 10 10 5], [5 5 6 6], 'r', 'EdgeColor','none')
grid
xticks(x)
yticks(y)
xlim([min(x) max(x)])
ylim([min(y) max(y)])

This could of course be generalised (using a for loop) to fill other squares. (I did not draw the diagnoal blue line because I do not know if it is significant. It would be straightforward to add it.)

.