Can I connect the dots ???

[James Darrell McCauley]

Bonnie Weller (weller at osiris.cso.uiuc.edu) writes on 13 September 1995:
>I have several points derived from a gps unit that I would
>like to convert into vector files, with the sites interconnected
>by arcs or lines.
>
>Is there a command that will do this or do I have to do this
>manually using digit ?

if you also have the GPS Time recorded, this would be easy:
 1. sort by time:
    given "x y z t," use 'sort -n +3'
 2. filter through awk to write a GRASS ASCII vector file.
 3. use 'v.in.ascii'

Without time, this may be somewhat more complex, depending
upon that path that the GPS unit traveled (e.g., sharp turns
and intersections). The naive approach would be to define a
starting point, calculate the distances to all other non-connected
points, find the smallest distance, and then connect to it.
This could be very time consuming---Helena and Irina's tree
library (quadtrees) could be used to take a lot of the brute-force
smell away (and significantly reduce computation).

Another approach may be to use the GEOM package (a 4.1 add-on)
and compute delaunay triangulation. This may not give you exactly 
what you want, but then again, it might make editing with v.digit
a lot easier (since you would only have to delete a bunch of lines,
not draw new ones).

So, no, there is no "connect the dots" program (that I am aware of), 
other than v.digit. However, it should not be dificult to write one.

Darrell
-- 
James Darrell McCauley, PhD           http://www.mcs.com/~mccauley/
16W518 Honeysuckle Rose Lane #214     mccauley at mcs.com
Hinsdale, Illinois 60521 USA          tel: 708.655.0643