Hi Arindam,
I understand that you have data for 180 (15x12) locations, about a trend for 163 years in the form of a 3-D matrix and wish to plot the trend at different locations.
Here are some steps that can be followed to achieve the plot:
- Use “squeeze” function to get the trend values for different years over the different latitude and longitude values.
- Use polynomial fitting using “polyfit” function to calculate the value of trend over the years.
- Create a mesh-grid for latitude and longitude.
- Plot the required trend.
Below is a sample code that performs the above discussed step taking random data to generate a similar plot.
% Assuming you have a 3-D matrix named 'data' with dimensions (lat, lon, time)
% Define the dimensions of the variable
lat = 15;
lon = 12;
time = 163;
% Get the size of the matrix
data = rand(lat, lon, time);
[latSize, lonSize, timeSize] = size(data);
% Preallocate arrays to store the trends and time values
trends = zeros(latSize, lonSize);
timeValues = 1:timeSize;
% Calculate the trend for each timeseries
for lat = 1:latSize
for lon = 1:lonSize
% Extract the timeseries at the current lat and lon
timeseries = squeeze(data(lat, lon, :));
% Calculate the trend using polynomial fitting
p = polyfit(timeValues, timeseries, 1);
% Store the trend value
trends(lat, lon) = p(1);
end
end
% Create a meshgrid for lat and lon
[lonGrid, latGrid] = meshgrid(1:lonSize, 1:latSize);
% Plot the trends
surf(lonGrid, latGrid, trends);
xlabel('Longitude');
ylabel('Latitude');
zlabel('Trend');
Please refer the shared documentation link for more information:
- squeeze: https://www.mathworks.com/help/matlab/ref/squeeze.html
- polyfit: https://www.mathworks.com/help/matlab/ref/polyfit.html
- meshgrid: https://www.mathworks.com/help/matlab/ref/meshgrid.html
- surf: https://www.mathworks.com/help/matlab/ref/surf.html
I hope this helps to plot the required data.
HTH
