how to clip a domain data from global data?
5 views (last 30 days)
Show older comments
I am trying to clip South Asia domain (19.25°E-116.25°E,-15.75°S-45.75°N) from a global dataset with 0.5 degree resolution.
Here is the code i am using:
global_data = load('global_data.mat');
% Define the latitude and longitude boundaries
lat_start = -15.75;
lat_end = 45.75;
lon_start = 19.25;
lon_end = 116.25;
% Define the resolution
resolution = 0.5;
% Calculate the indices for cropping
lat_indices = floor((lat_start + 90) / resolution) + 1 : floor((lat_end + 90) / resolution) + 1;
lon_indices = floor((lon_start + 180) / resolution) + 1 : floor((lon_end + 180) / resolution) + 1;
% Crop the global data
cropped_data = global_data(lat_indices, lon_indices, :);
% Display the size of the cropped data
disp(size(cropped_data));
Can someone help me with this?
Thank you.
0 Comments
Answers (2)
Sulaymon Eshkabilov
on 28 Jun 2023
Here are two ways to get it with two small corrections in your code:
Way - 1. Just use load() without variable name assigning, because the variable name is the same:
load('global_data.mat');
% Define the latitude and longitude boundaries
lat_start = -15.75;
lat_end = 45.75;
lon_start = 19.25;
lon_end = 116.25;
% Define the resolution
resolution = 0.5;
% Calculate the indices for cropping
lat_indices = floor((lat_start + 90) / resolution) + 1 : floor((lat_end + 90) / resolution) + 1;
lon_indices = floor((lon_start + 180) / resolution) + 1 : floor((lon_end + 180) / resolution) + 1;
% Crop the global data
cropped_data = global_data(lat_indices, lon_indices, :);
% Display the size of the cropped data
disp(size(cropped_data));
Way - 2. Read data from Stucture variable, e.g.: global_data.global_data
global_data = load('global_data.mat');
global_data = load('global_data.mat');
% Define the latitude and longitude boundaries
lat_start = -15.75;
lat_end = 45.75;
lon_start = 19.25;
lon_end = 116.25;
% Define the resolution
resolution = 0.5;
% Calculate the indices for cropping
lat_indices = floor((lat_start + 90) / resolution) + 1 : floor((lat_end + 90) / resolution) + 1;
lon_indices = floor((lon_start + 180) / resolution) + 1 : floor((lon_end + 180) / resolution) + 1;
% Crop the global data
cropped_data = global_data.global_data(lat_indices, lon_indices, :);
% Display the size of the cropped data
disp(size(cropped_data));
Sulaymon Eshkabilov
on 28 Jun 2023
If understood your question correctly, what you want is to display your cropped data, right?
If so, here is how it can be done:
load('global_data.mat');
% Define the latitude and longitude boundaries
lat_start = -15.75;
lat_end = 45.75;
lon_start = 19.25;
lon_end = 116.25;
% Define the resolution
resolution = 0.5;
% Calculate the indices for cropping
lat_indices = floor((lat_start + 90) / resolution) + 1 : floor((lat_end + 90) / resolution) + 1;
lon_indices = floor((lon_start + 180) / resolution) + 1 : floor((lon_end + 180) / resolution) + 1;
% Crop the global data
cropped_data = global_data(lat_indices, lon_indices, :);
% Display the size of the cropped data
disp(size(cropped_data));
figure
imagesc(cropped_data(:,:,1)) % Cropped data set
figure
imagesc(global_data(:,:,1)) % Whole data set
In order to create the two image as you mentioned, you need to specify the corodinates (indices) as in this cropped one.
See Also
Categories
Find more on Data Import and Analysis in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!