how do i plot a coordinate field with values for each specified coordinate?

the coordinate field:

y = 1:0.5:31;

x = -13:1:13;

[X,Y] = meshgrid (z,y);

But from here i have no clue which command to use to give each coordinate a value and plot with colormap afterwards.

I already have a .txt file with every value organized. So data (1,1) should become mesh (-13,1) and data (1,2) should be mesh (-12,1)

thanks in advance!

Answer 1

[Soumya]

Hi @jop schilder,

I understand that you have a coordinate field defined by some given ‘x’ and ‘y’ values, where each point on this grid should correspond to a value from a ‘.txt’ file. To solve this, you should load your ‘.txt’ file as a matrix, matching the grid size, then use MATLAB’s plotting functions such as ‘imagesc’ for a 2D heatmap, ‘surf’ for a 3D surface, or ‘contourf’ for filled contour plots visualization to map and display the values with a colormap.

Kindly refer to the given steps to achieve the same:

• Create the mesh grid and load your data from the “.txt” file:

[X, Y] = meshgrid(x, y); 
data = load('file.txt'); 

• You can visualize the data as a 2D heatmap using a colormap, where each matrix value is automatically mapped to its corresponding (x, y) coordinate:

imagesc(X,Y, data); 
axis xy; 
colormap jet; 
colorbar; 

• You can also visualize the data as a 3D surface plot, which helps illustrate value variations across three dimensions with smooth color interpolation:

surf(X, Y, data) 
shading interp 
colormap jet 
colorbar 
xlabel('X'); ylabel('Y'); zlabel('Value') 

The above code generates the following output:

Please refer to the following documentations to get more information on the related functions: 

• surf: https://www.mathworks.com/help/matlab/ref/surf.html
• imagesc: https://www.mathworks.com/help/matlab/ref/imagesc.html
• colormap: https://www.mathworks.com/help/matlab/ref/colormap.html
• colorbar: https://www.mathworks.com/help/matlab/ref/colorbar.html

I hope this helps!