How can I incorporate the angle of orientation in my colourmap?

Hi,

I am currently producing colourmaps for my degree of orientation data. This data varies between 0-180 degrees. Producing colormaps works nicely, however, I am thinking there might be a better way to demonstrate angle.

Is it possible for each data point to be a line, which represents the angle at said data point? i.e. at 180 degrees, it is a vertical line.

This is my current code for my colormap:

%Import the data in from excel
num = xlsread('ExampleData')

% Reshape the intensity vector into a matrix
[xUnq,~,xIdx] = unique(num(:,1)); 
[yUnq,~,yIdx] = unique(num(:,2)); 
zMat = nan(numel(yUnq),numel(xUnq)); 
zIdx = sub2ind(size(zMat),yIdx,xIdx);
zMat(zIdx) = num(:,3);
% Plot contour
contourf(xUnq,yUnq,zMat)
pcolor(xUnq,yUnq,zMat)
shading interp
colorbar
% Label colour bar
c = colorbar;
c.Label.String = ('Degree of Orientation (\theta)');
ylabel('\mu m')
xlabel( '\mu m')
title('title')

I have attached some example data I have been playing with:

Answer 1

[Turlough Hughes]

To represent the orientations with arrows, you could a quiver plot as follows:

%Import the data
data = readmatrix('https://uk.mathworks.com/matlabcentral/answers/uploaded_files/880780/ExampleData.xlsx');

figure()
theta = data(:,3);
quiver(data(:,1),data(:,2),cosd(theta),sind(theta),'LineWidth',2, ...
    'AutoScaleFactor', 0.6)

ylabel([char(181) 'm']) % char(181) is just a preference
xlabel([char(181) 'm'])
title('Orientation Map')

axis padded
set(gca,'FontSize',14)

[Sam]

Thank you so much, I wasn't aware of quiver plots - this looks great!

[Turlough Hughes]

You can scale the third and fourth inputs to quiver as follows:

data = readmatrix('https://uk.mathworks.com/matlabcentral/answers/uploaded_files/880780/ExampleData.xlsx');
figure()
theta = data(:,3);

s = 0.4;
quiver(data(:,1),data(:,2),s*cosd(theta),s*sind(theta),'LineWidth',2, ...
    'AutoScale', 'off', 'MaxHeadSize', 0.1)
axis equal

ylabel([char(181) 'm']) % char(181) is just a preference
xlabel([char(181) 'm'])
title('Orientation Map')
axis padded
set(gca,'FontSize',14)