[R-sig-Geo] shortest realistic distance for fish travel

[Jon Loehrke]

Hi,

	I am trying to find an algorithm or thoughts on approach for how to  
compute the shortest realistic distance between two points.  I define  
shortest realistic distance as the shortest distance between two  
points that a fish (which is what I study) could move through.  Hence  
the path must wrap around land, islands, archipelagos, etc.

Point 1

41.15  	N
71.26 	W

Point 2

42.17  	N
70.37 	W

	I'm sure this issue has come up with the geo-statistical community,  
but simply need a starting direction.

Thank much and happy holidays.

Jon Loehrke
Graduate Research Assistant
Department of Fisheries Oceanography
School for Marine Science and Technology
University of Massachusetts
200 Mill Road, Suite 325
Fairhaven, MA 02719
jloehrke at umassd.edu
T 508-910-6393
F 508-910-6396