how to find distance between two points?

Hai,

I need to find the distance between two points in the figure, which I have plotted. Is there any function in matlab that could find the distance between two points. Looking for your reply.

BSD

Answer 1

[Lucas García]

You can use the pdist function in the Statistics Toolbox:

e.g: distance between points (0,0) and (2,1)

>> X = [0,0;2,1];
>> d = pdist(X,'euclidean')
d =

    2.2361

[manish sharma]

That worked for me. Thanks Lucas :)

[Mohd Aaqib Lone]

Hi Lucas García,

I want to measure distance between one point to other more than ten points, what i mean is like i have ten markers on one line and i want to compute distance from the ist marker with other 9 markers. How can I do it in MATLAB. Please answer.

[zoher badr]

in this case you have to have a nested loop so you gaurantee to reach each point int the list

Answer 2

[MathWorks Support Team]

The distance between two points x and y is the same as the magnitude of the vector that points from one point to the other:

>> x = [0 0];
>> y = [2 1];
>> norm(x-y)

ans =

      2.2361

[Peize Li]

Will i get a column vector of distances if I try norm(x-y), where x and y are two 3 x 2 vectors?

[Advik Solanki]

thanks

Answer 3

[Walter Roberson]

No. You will have to code it yourself.

There are many different possible meanings for "distance". See http://en.wikipedia.org/wiki/Metric_%28mathematics%29#Examples

Answer 4

[Fangjun Jiang]

Pos=[x1 x2;y1 y2]
D=dist(Pos);

[Walter Roberson]

Which "dist" function are you referring to, Fangjun ? The only one I find is in the Neural Networks toolbox, and it returns a matrix of distances rather than a single distance.

http://www.mathworks.com/help/toolbox/nnet/ref/dist.html

[Fangjun Jiang]

@Walter, just the dist() function in MATLAB, not associated to any particular Toolbox. help dist or doc dist will brings it up.

There are many call syntax of dist(). I though the OP wants the Euclidean distance between two points (x1,y1), (x2,y2), which should be sqrt((x1-x2)^2+(y1-y2)^2).

dist() can calculate the Euclidean distance of multiple points at once, it can certainly be used to calculate the distance for two points, although it seems to be an over-kill because the equation sqrt((x1-x2)^2+(y1-y2)^2) can do that too.

Since the OP asked for a MATLAB function, I thought this is the one.

pos=rand(2,5)

D=dist(pos)

[Fangjun Jiang]

Sorry, Walter. You are right, the dist() function is from the Neural Network Toolbox.

[Fangjun Jiang]

I am using my new MATLAB version today. It has a bunch of toolbox. Nice!

Answer 5

[Twinkle Jain]

 X = [0,0;2,1];
 d = pdist(X,'euclidean')

Answer 6

[Sohrab Dorodvand]

if i was to compare one point of a 1d graph and to compare the distances between that point(the reference point) to others on the graph. how can i do that?

Answer 7

[Daksh]

I understand you're experiencing doubts over calculating distance between 2 points in the figure for which you have variable values saved in workspace. You can use one of the following methods for your utility:

1. norm(): distance between two points as the norm of the difference between the vector elements
2. pdist(X): Euclidean distance between pairs of observations in X
3. pdist2(X,Y,Distance): distance between each pair of observations in X and Y using the metric specified by Distance.
4. distance(): distance between two points in Geographic space

Hope this helps!