Need to plot speed heatmap
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I have an excel sheet having data of time, distance(postmile) and speed in three columns
I have to plot 2d high resolution heatmap of speed as follows; time in x-axis, distance(postmile) in y axis and speed in z axis with color. Can anyone help me to provide matlab code for this
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1323475/image.jpeg)
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Answers (1)
Anurag Ojha
on 14 Mar 2023
Hi, Laxmi
To draw a heatmap for 3 variables you can simply turn your data into an image, for example, a 1000x1000 image. Then display the image using “imshow” or “image” and then use “colormap” and “colorbar”.
%Taken 3 variables in your case time,displacement and speed
x = 1:100;
y = 2:102;
z = 50:150;
% Doing this so that any unassigned values
% (like you don't have every single possible x and y value in your data) will be
% set to the mean value of what data you do have.
minx = min(x);
maxx = max(x);
miny = min(y);
maxy = max(y);
meanValue = mean(z);
heatMapImage = meanValue * ones(1000, 1000);
% Here creating the heatmap and storing it in heatMapImage array
for k = 1 : length(x)
column = round( (x(k) - minx) * 100 / (maxx-minx) ) + 1;
row = round( (y(k) - miny) * 100 / (maxy-miny) ) + 1;
heatMapImage(row, column) = z(k);
end
%Convert the array to image using imshow and adding colorbar
imshow(heatMapImage, []);
colormap('hot');
colorbar;
To further explore you can refer to below links:
Hope it helps!
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