MATLAB: Get distance between adjacent array cells

Question

Hello everyone,

I have a little problem calculating a velocity from a distance matrix. I do have the time array already.

My distance matrix looks as following:

dist=[x_coord1, y_coord1;
      x_coord2, y_coord2;
      ....];

The coordinates are absolute, and I need the relative distance between the current coordinates and the previous one.

So, my vector should look like this:

newdist=[pdist2([x_coord2,y_coord2],[x_coord1,y_coord1]);
         pdist2([x_coord3,y_coord3],[x_coord2,y_coord2])
         ......];

But instead pdist2 gives a vector with the distance of every possible combination of cells.

My questions(in my opinion at least):

1. Are there any functions which give me what I want immediately; or if this is not the case

2. Is there a way to decipher the pdist2 vector and get the correct values?

Thanks for reading this long post and helping 🙂

Kind regards, Dries van Roovert

Answer 1

For anyone interested in the answer:

PairwiseDist=squareform(pdist(dist,'euclidean'));
RelativeDist=diag(PairwiseDist,-1);

You'll get the distance from coord 2 to 1, coord 3 to 2, ... and so on in a vector.

Cheers