plot 2D matrix data

I have a numeric matrix array, with column 1 containing the x coordinate, column 2 containing the y coordinate, and column 3 containing the value at that xy position. How can I create a reliable 2d pcolor plot from this matrix?

Answer 1

[Star Strider]

The pcolor function requires a matrix argument, and the data provided here are a (5000 x 3) matrix with ‘X’, ‘Y’ and ‘Z’ columns. Creating a matrix from this is necessary if you want to use image, pcolor, or other such functions.

I would skip that and just use scatter3 and then rotate it using the view function:

LD = load('data.mat');
data25um = LD.data25um;

figure
scatter3(data25um(:,1), data25um(:,2), data25um(:,3), [], data25um(:,3), 's', 'filled')
grid on
xlabel('X')
ylabel('Y')
view(0,90)
axis('tight')

producing:

.

.

Answer 2

[darova]

Use griddata to create matrices

[Sam Hurrell]

How can I use griddata for the data in its current form? The examples I've looked at seem to give values based on defined calculations rather from a data array?