Calculating distance between two point layers through a polygon layer

Discussion created by tj_lawson on Sep 10, 2013
Latest reply on Sep 17, 2013 by xander_bakker

I have two point layers, one representing river mouths and the other representing beach sites. I also have a water polygon layer. I am trying to calculate the shortest distance from my beach site layer to the nearest river mouth but it has to be through the water layer. The proximity tools wont work as they calculate the shortest distance but in areas where there i have a beach site on one side of a headland and a river mouth on the other it will take the path across land but i need it to go through the water. I also can't use the outline of the coast as a network along which to travel as in areas like the Gulf, the shortest distance will be straight across not via the coastline. Any suggestions?