Colormap a plot based on value of (x,y)

Hello,

I have a table T of dimensions x,y where each point has a value between -100 and 100.

I want to graph this data such that T(1,1) is point 1,1 on the graph and the color of that point is determined by the value of T(1,1)

I included a picture of something similar to what I want my plot to look like, along with some code that generates an example table for graphing

Thanks in advance for any help you can provide.

clear

clc

close all

%This will generate a table with example data.

x=100

y=50

data=zeros(y,x);

data(1,1)=50;

dchartdx=25/x;

dchartdy=25/y;

for ii=1:x

data(1,ii+1)=data(1,ii)+dchartdx;

end

for ii=1:x+1

for ij=1:y

data(ij+1,ii)=data(ij,ii)+dchartdy;

end

end

[DGM]

Try imagesc(). If you want explicit control over the colormap limits, use clim().

imagesc(data) % display the data with the colormap ends corresponding to the data extrema
colorbar % add a colorbar
colormap(jet(256)) % specify a colormap

Answer 1

[Manikanta Aditya]

Hi,

The image you've provided shows a depth vs range plot, likely representing some kind of acoustic or seismic data.

To create a similar plot using MATLAB with your data, you can use the 'imagesc' function as mentioned by @DGM.

Here's the script with the changes:

clear
clc
close all

% Generate example data
x = 100;
y = 50;
data = zeros(y, x);

% Fill the data array (your existing code)
data(1,1) = 50;
dchartdx = 25/x;
dchartdy = 25/y;
for ii = 1:x
    data(1,ii+1) = data(1,ii) + dchartdx;
end
for ii = 1:x+1
    for ij = 1:y
        data(ij+1,ii) = data(ij,ii) + dchartdy;
    end
end

% Create the plot
figure;
imagesc(1:x, 1:y, data); % display the data with the colormap ends corresponding to the data extrema
colormap(flipud(hot)); % specify a colormap
colorbar; % add a colorbar

% Set axis labels and title
xlabel('Range (km)');
ylabel('Depth (m)');
title('Data Visualization');

% Invert the y-axis to have (1,1) at the top-left corner
set(gca, 'YDir', 'reverse');

% Adjust aspect ratio if needed
axis equal tight

I hope this helps!