||contiguous, starting from '0'
||Sample 0, representing the soma,
has parent -1.
Tree root sample have parent 0.
'y', 'z' are spatial co-ordinates, given in micrometers.
'length' is the scalar distance between this point and its parent.
'diameter' is dendrite thickness, also given in micrometers.
In the case of the first point,it repesent a cylinder of dimensions length x diameter.