How to Create Plot of Weights at Spatial Locations (Connectivity Map)

I am wondering what tools in Matlab are available to create a plot of "connectivities" between different spatial locations. Basically, I have locations of data (I and P) as well as weights (f_IP) indicating the strength of the connection between each I and P, pointing from I to P. The plot I desire to create looks like the below:

Again, there are P weights pointing from each I toward each P. Larger weights are of larger size on the plot. Looking around, I have found Matlab functions that do similar things, but nothing quite like what I am looking for. Any guidance/recommendations would be appreciated.

Answer 1

[Kelly Kearney]

There aren't any pre-packaged functions to do this, but it should be pretty straightforward to create a function the calculates the vertices of each triangle shape given the coordinates of a P/I pair and the weight connecting them. You can then plot it as a multi-faceted patch. Example to come if I get some free time tomorrow...

[Corey Hoydic]

Hello Kelly - thank you for this. I will attempt implementation on my end in the meantime.

[Kelly Kearney]

An example... adjust as needed:

% Coordinates of I and P points

Ixy = [...
     0 20
    20 20
    10 10
     0  0
    20  0];
Pxy = [...
    10 20
     0 10
    20 10
    10  0];

% Weights connecting I (rows) to P (columns)

w = [...
    2 2 1 1
    2 1 2 1
    2 2 2 2
    1 2 1 2
    1 1 2 2]*2;

% Calculate angles between each I/P pair

[xi, xp] = ndgrid(Ixy(:,1), Pxy(:,1));
[yi, yp] = ndgrid(Ixy(:,2), Pxy(:,2));
dx = xp - xi;
dy = yp - yi;

ang = atan2(dy,dx);

% Calculate coordinates of triangles

dang = pi/30;

xpatch = [xi(:) xi(:)+w(:).*cos(ang(:)+dang) xi(:)+w(:).*cos(ang(:)-dang)]';
ypatch = [yi(:) yi(:)+w(:).*sin(ang(:)+dang) yi(:)+w(:).*sin(ang(:)-dang)]';

% Plot

patch(xpatch, ypatch, 'g');
axis equal;

text(Ixy(:,1), Ixy(:,2), compose('I%d', 1:size(Ixy,1)), 'horiz', 'center');
text(Pxy(:,1), Pxy(:,2), compose('P%d', 1:size(Pxy,1)), 'horiz', 'center');