How to find distance between points in every grid?

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Sevil Cansu Yildirim 2020-1-27

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https://ww2.mathworks.cn/matlabcentral/answers/502103-how-to-find-distance-between-points-in-every-grid

评论： Walter Roberson 2020-1-28

Hello, I defined a grid onto a map that I plotted with MAP library. This grid contains some elements and I know the density of each grid (which one contains what amount of elements). But now I need to find which element belongs to which grid and calculate distance between these points belonging to same grid.

Here is my code, and you can find the data and the figure attached. Thank you from now.

clear all;figure;
addpath('D:\Desktop\BOUN\JOB\Slip_Rates\Slip_Data\MAP');
LAT1=39;LAT2=42;LON1=29.0;LON2=41.0;
sf = 1;
m_proj('albers equal-area','lat',[LAT1 LAT2],'long',[LON1 LON2],'rect','on');m_gshhs_h('color',[.5 .5 .5]);hold on; 
m_grid('linewi',1,'linest','none','tickdir','in','fontsize',10);
all = load('all_velocities.txt');
lon1=all(:,1);lat1=all(:,2);ve1=all(:,3);vn1=all(:,4);
%[lon1,lat1,ve1,vn1,sve1,svn1] = textread('all_velocities.txt','%f %f %f %f %f %f'); % REFERENCE
%density of the grids
dLO = .5*2; dLA = .3636*2;
lon = [LON1:dLO:LON2];  % grid size longitude
lat = [LAT1:dLA:LAT2];  % grid size latitude
for i = 1:length(lat)
    for j = 1:length(lon)
        DENSITY(i,j) = length(find(abs(lat1-lat(i))<dLA/2 & (abs(lon1-lon(j))<dLO/2)));
    end
end
% distance between vectors in every single defined grids
z = 1;
for i = 1:length(lat)
    for j = 1:length(lon)
        ind = find(abs(lat1-lat(i))<dLA/2 & (abs(lon1-lon(j))<dLO/2));
        for k = 1:length(ind)
            points(z,:) = [lat1(ind(k)) lon1(ind(k))];
            DIST = pdist(points, 'euclidean');
            z = z+1;
        end
    end
end
m_pcolor(lon-dLO/2,lat-dLA/2,DENSITY);colormap(jet);colorbar;
m_quiver(lon1,lat1,sf.*ve1,sf.*vn1,1,'w','filled','AutoScale','off','linewidth',1.5);
hold off;