how to plot 4D figure to describe changing in ocean ?

Hi,

I have the oceanographic data ( Longitude , Latitude , Density ,Depth)

I want to plot the change of density with depth such as the picture

I try to plot with surf but give me the surface changing

Also I try slice but did’t work because my data is 2D

Longitude =300*400,

Latitude =300*400 ,

Density =300*400,

Depth =300*400

Answer 1

[Voss]

"I try to plot with surf but give me the surface changing"

How did you use surf, and what was wrong with the result?

Have you tried the following?

surf(Longitude,Latitude,Depth,Density)

[Amal MM]

yes I did it give this plot

I want plot somting similar like this

[Voss]

colormap(jet())

Answer 2

[Umar]

Hi @Amal MM ,

After reading through your comments, it seems that your task involves visualizing oceanographic data, specifically the relationship between density and depth across a grid defined by longitude and latitude. The data is structured in a 2D format, but your goal is to create a plot that effectively represents the changes in density with depth. Now, the challenge arises from the need to represent this data in a way that is both informative and visually appealing, while also addressing the limitations of the surf and slice functions in MATLAB.

So, to visualize the oceanographic data effectively, you can utilize MATLAB's scatter3 function to create a 3D scatter plot, where you a represent density as color and depth as the z-axis. This approach will allows you to convey the fourth dimension (density) through color coding, while maintaining a clear representation of the spatial dimensions (longitude and latitude) and depth. Since you mentioned that your data is structured as 300x400 matrices for longitude, latitude, density, and depth, we will create synthetic data for demonstration purposes. Convert the 2D matrices into vectors to facilitate plotting. Use scatter3 to plot the data, where the x-axis represents longitude, the y-axis represents latitude, the z-axis represents depth, and the color represents density. Add labels, a color bar, and a title to make the plot more informative. Here is a complete MATLAB code snippet that implements the above steps:

_% Generate Sample Data_
longitude = linspace(-180, 180, 400); % Longitude from -180 to 180
latitude = linspace(-90, 90, 300);    % Latitude from -90 to 90
[lon, lat] = meshgrid(longitude, latitude); % Create a grid of longitude and   
latitude

_% Create synthetic depth and density data_
depth = rand(size(lon)) * 5000; % Depth values between 0 and 5000 meters
density = 1025 + (depth / 5000) * 5; % Density values, increasing with depth

_% Reshape the Data_
lon_vector = lon(:);
lat_vector = lat(:);
depth_vector = depth(:);
density_vector = density(:);

_% Create the 3D Scatter Plot_
figure;
scatter3(lon_vector, lat_vector, depth_vector, 36, density_vector, 'filled');
view(3); % Set the view to 3D
grid on;

For more information on scatter3 function, please refer to

https://www.mathworks.com/help/matlab/ref/scatter3.html

_% Enhance Visualization_
xlabel('Longitude (degrees)');
ylabel('Latitude (degrees)');
zlabel('Depth (meters)');
title('Density Variation with Depth in Oceanographic Data');
colorbar; % Add a color bar to indicate density values
colormap(jet); % Use a colormap for better visualization

For more information on colormap(jet) function, please refer to

https://www.mathworks.com/help/matlab/ref/jet.html?s_tid=doc_ta

Please see attached.

Feel free to adjust the synthetic data generation to match your actual oceanographic data for more accurate visualizations.

Please let me know if you have any further questions.

[Amal MM]

Thanx for your time I really appreciate but it not work I want to plot as polyhedron

[Umar]

Hi @Amal MM ,

The modified code below meets your requirements for creating a 4D plot that describes changes in oceanographic conditions by synthesizing relevant data and employing advanced visualization techniques based on explanation of code provided below.

% Define the number of data points
numPoints = 500;

% Generate synthetic Longitude and Latitude data
Longitude = -180 + (180 + 180) * rand(numPoints, 1); % Range: -180 to 180
Latitude = -90 + (90 + 90) * rand(numPoints, 1); % Range: -90 to 90

% Generate synthetic Depth data (in meters)
Depth = -1000 * rand(numPoints, 1); % Depth values between 0 and -1000   
meters

% Generate synthetic Temperature data (in degrees Celsius)
% Assuming a linear relationship with depth for simplicity
Temperature = 20 + (Depth / -1000) * 15; % Temperature decreases with depth

% Create the VPSA table
VPSA = table(Longitude, Latitude, Depth, Temperature);

% Extract data from the VPSA table
X = VPSA.Longitude; % Longitude
Y = VPSA.Latitude; % Latitude
Z = VPSA.Depth; % Depth
C = VPSA.Temperature; % Temperature

% Create a grid for interpolation
xi = linspace(min(X), max(X), 1000); % Longitude grid
yi = linspace(min(Y), max(Y), 1000); % Latitude grid
[Xi, Yi] = meshgrid(xi, yi); % Create a mesh grid

% Interpolate Depth and Temperature
Zi = griddata(X, Y, Z, Xi, Yi); % Interpolated Depth
Ci = griddata(X, Y, C, Xi, Yi); % Interpolated Temperature

% Create the surface plot
figure;
surf(Xi, Yi, -Zi, Ci); % Use -Zi to invert the depth for visualization
shading interp; % Interpolated shading for a smoother appearance
colorbar; % Add a color bar to indicate temperature values
colormap(jet); % Use the 'jet' colormap for better visualization

% Enhance Visualization
xlabel('Longitude (degrees)');
ylabel('Latitude (degrees)');
zlabel('Depth (meters)');
title('Oceanographic Data: Temperature Variation with Depth');
view(3); % Set the view to 3D
grid on; % Enable grid for better visibility

Please see attached.

Data Generation

The code generates synthetic data for Longitude, Latitude, Depth, and Temperature. This is important as it allows for a realistic simulation of ocean conditions without requiring actual data.

Longitude and Latitude: Randomly generated within their respective global ranges (-180 to 180 degrees for Longitude and -90 to 90 degrees for Latitude).

Depth: Synthesized to represent depths ranging from 0 to -1000 meters, simulating typical ocean depths.

Temperature: Assumed to have a linear relationship with depth, indicating that temperature decreases as depth increases. This is a simplification of real oceanographic conditions but serves well for illustrative purposes.

Data Structuring

A table VPSA is created to organize the generated data efficiently. This structure aids in managing multiple dimensions of data simultaneously.

Interpolation

The use of griddata allows for interpolation of Depth and Temperature across a grid defined by the generated Longitude and Latitude values. Interpolation is critical in oceanography as it helps visualize data over continuous surfaces rather than discrete points.

Creating a mesh grid (Xi, Yi) enables smoother transitions between points, enhancing visual clarity.

Visualization

The code employs surf to create a surface plot, which effectively represents three-dimensional data (Longitude, Latitude, Depth) while using color (Temperature) to add a fourth dimension.

The use of -Zi in the plot command ensures that depth is represented correctly (with deeper areas shown lower on the graph).

Additional enhancements like color mapping (colormap(jet)) and shading (shading interp) improve the visual output by providing clear distinctions between temperature variations.

Final Touches

Labels for axes and a title provide context to the viewer about what the plot represents.

The view(3) command sets up a three-dimensional view, allowing users to appreciate depth in the visualization.

Please let me know if you have any further questions.

[Umar]

Hi @Amal MM,

Please let me know if you still require further assistance or need help.

[Amal MM]

thanx

[Umar]

Hi @Amal MM,

Thank you for your response. I appreciate your acknowledgment. If there’s anything specific you would like to discuss further or if you have additional thoughts, please feel free to share.