[GRASSLIST:5916] Shore Normal transect

[John Chesnut]

I need to create shore normal transects from established  sampling 
points at Salton Sea, Ca.

How do I automate this in GRASS ?
The tangent point of a radius around the sample would work for this 
relatively simple coastline.

In ArcView a "join" calculation records a tangent distance between 
features. Is there a similar calculation available in GRASS. or do I 
need to make a looping calculation that increments a radius until a 
tangent solution is reached ?

A more complex coastline would require "smoothing".  The  normal 
vector including  the sample point would  describe the shore normal 
transect.  This approach would require selection and creation of 
seg,ments of the "smoothed" coastline.   How would I automate the 
selection process and store the locally smoothed segments.