How to plot magnitude and directions between 2 points?

Hi,

I have a set of stations coordinates in a text file. The stations coordinates consist of positions of 2 points (X1, Y1) and (X2, Y2) at 50 stations. How do I plot/visualize the magnitude and direction of the stations coordinate to see the the changes in distance and direction?

Basically I want the plot to look like this [x1, y1]--------->[x2, y2] (with correct magnitude and direction) but for 50 stations.

I have tried the function quiver, but still cannot plot all the 50 stations.

Can somebody show me how to plot the magnitude and direction for 50 stations?

Thank you.

[darova]

Can you attach your attempts? And how do you want magnitude and direction to look like?

[Adilla Zulkifli]

Attached is the input file in text file format. I would like to have Point 1A (X2, Y2) with magnitude and direction towards Point 1B (X1, Y1) which looks like an arrow. But the total of points I have are 50. So basically, the plot is supposed to have 50 arrows with magnitude and direction.

I have already tried using this coding but it doesn't work ;

data = load ('Input.txt');

[row, col] = size (data);

Y2 = data (:,1);

X2 = data (:,2);

Y1 = data (:,3);

X1 = data (:,4);

format long

delta_X = X2 - X1;

delta_Y = Y2 - Y1;

magnitude = sqrt(((delta_X).^2)+((delta_Y).^2));

format short

direction = wrapTo360(radtodeg(atan2(delta_X,delta_Y)));

P1 = [X2 Y2];

P2 = [X1 Y1] ;

DP = P2-P1;

figure(1)

quiver(P1(1),P1(2),DP(1),DP(2),0)

grid

Answer 1

[darova]

try this (not tested)

data = load ('Input.txt');
[row, col] = size (data);
Y2 = data (:,1);
X2 = data (:,2);
Y1 = data (:,3);
X1 = data (:,4);
delta_X = X2 - X1;
delta_Y = Y2 - Y1;  
magnitude = sqrt(((delta_X).^2)+((delta_Y).^2));
cm = jet(50);                    % create colormap
ind = 1 + round(magnitude/max(magnitude)*49);    % convert magnitude to index
plot(0,0)
hold on
for i = 1:length(X1)
    quiver(X1(i),Y(i),delta_X(i),delta_Y(i),'color',cm(ind(i)))
end
hold off

[Adilla Zulkifli]

Thank you for the suggestion. I have tried the coding but an error using quiver appeared stating that 'Color value must be a 3 element vector'. The error in in this line;

quiver(X2(i),Y2(i),delta_X(i),delta_Y(i),'color',cm(ind(i)))

[darova]

Should be

quiver(X1(i),Y(i),delta_X(i),delta_Y(i),'color',cm(ind(i),:))

[Adilla Zulkifli]

The error is no longer persists. I only need to scale the delta_X and delta_Y. Due to small displacement, the arrow can't really be seen. Thank you for your help.

[darova]

Look HERE

[Adilla Zulkifli]

Yes. I already did that. Thank you again :)