Removing negative values of 3d data
5 views (last 30 days)
Show older comments
Hello, I have a diagram where I want to get rid of the lower portion (the points which have negative z value) so I can use scatteredInterpolant on it. How would I do this?
The points are stored in a 3D array with index (1,1,1) being an x-value, (1,1,2) being the corresponding y value and (1,1,3) being the corresponding z value.
Thanks!
Accepted Answer
Chunru
on 18 Apr 2022
Edited: Chunru
on 19 Apr 2022
x = load("ggv.mat");
GGV = x.GGV;
figure
surf(GGV(:,:,2), GGV(:,:,3), GGV(:,:,1), 'EdgeColor', 'none');
xlabel('x'); ylabel('y')
figure
% to demonstrate limit works for X data (Z in the plot)
surf(GGV(:,:,2), GGV(:,:,3), max(GGV(:,:,1), -20), 'EdgeColor', 'none'); % -20 and above
xlabel('x'); ylabel('y')
% The number of points for z<0
sum(GGV(:, :, 3) < 0, 'all')
min(GGV(:, :, 3), [], 'all')
figure
% limit z data here will not make no change since no z is less than 0
surf(GGV(:,:,2), max(GGV(:,:,3), 0), GGV(:,:,1), 'EdgeColor', 'none');
xlabel('x'); ylabel('y')
figure
% limit GGV(:,:,1)
surf(GGV(:,:,2), GGV(:,:,3), max(GGV(:,:,1), 0), 'EdgeColor', 'none');
xlabel('x'); ylabel('y')
zlim([-80 20])
3 Comments
Tim Albertsson
on 16 Feb 2024
Hi! How did you get the GGV points from the start? I'm trying to make my own script for this and I've gotten the max lat and lon accelerations for the different speeds but not the full (GG "elipse").
More Answers (1)
Chunru
on 18 Apr 2022
% Your data
data = randn(357, 177, 3);
% limit to 0
data(:, :, 3) = max(data(:, :, 3), 0); % to limit the surface up to 0
% You may also want to try nan (depending on how you plot the data)
idx = data(:, :, 3) < 0;
data(idx, 3) = nan;
See Also
Categories
Find more on Historical Contests in Help Center and File Exchange
Products
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!