Return number of elements in coordinate trace.
l=length(t)
When applied to an imat_ctrace object, the LENGTH function returns the length of the coordinate trace (i.e., the number of coordinates).
>> t=imat_ctrace('1x','2x','3x','4x')
t =
'1X+'
'2X+'
'3X+'
'4X+'
>> length(t)
ans =
4
>>