CODEWITHSUNDEEP
matlabrandomgraphmatlab-figuredistance
Charles Reed
Charles Reed

Reputation: 33

Over graphing points

I'm trying to randomly create 100 points from 0 - 180, then graph them. Then check the distance between them and if it falls under a certain threshold draw a line between them. I can get the points graphed, and even some lines. But it's not right, some points that are close enough aren't mapped, and some points that are further are mapped.

clc; clear all; format compact;
a = [2 3]
b = [16 50]

array = randi(180,100,1);
array2 = randi(180,100,1);
% x = array(:, 1);
% y = array(:,2);
plot(array,array2, '.')
line (a,b)
% radius is 18, which is given k * given d
for j = 1:100
    for i = 1:100
        d = sqrt((array(j)-array(i))^2+(array2(j)-array2(i))^2);
        if d <= 18
           point1 = [array(j), array2(j)];
           point2 = [array(i), array2(i)];
           line( point1, point2)
        end
    end
end

Sample output:

Sample output

Upvotes: 0

Views: 36

Answers (1)

Cris Luengo
Cris Luengo

Reputation: 60574

I see the issue now. line doesn't draw a line from one point to the next, it draws a line through given x and y coordinates, much like plot. Replace this bit:

point1 = [array(j), array2(j)];
point2 = [array(i), array2(i)];
line( point1, point2)

with this:

x = [array(i), array(j)];
y = [array2(i), array2(j)];
line(x, y);

or equivalently:

line(array([i,j]),array2([i,j]));

Unsolicited advice:

Use more sensical names than array and array2. For example x and y. This bug would have been easy to spot with better names!

Upvotes: 1

Related Questions