title: matlab, measure of spatial spread
body: <p>Having data points in a 3D neighbourhood (see attached picture), I would like to define a measure of spatial spread to accept or reject the data set as a candidate for further analysis. One measure could be how many of the cells in the 3D subvolume (the bounding box) are occupied by the neighbourhood. Another would be how the data stretches along each of the axis. Are there other and better criteria for measuring the spatial spread ?
  Thanks
  <img src="https://i.stack.imgur.com/Tq9pj.png" alt="enter image description here"></p>