I am trying to calculate the shortest distance from a large number of points (created using 'genvecgrid' in Geospatial Modelling Environment) to both a single point (representing the breeding beach) and a line (representing the coastal shelf drop-off). The overall goal here is to find for every point the distance from the beach and coastal shelf to each grid point which will let me analyse at-sea resource selection of the penguins being studied.
The problematic part is that the distances need to travel around the coast, so they are representative of the shortest distance a penguin could travel by sea between the points. The breeding site (beach) is on the outside of a peninsula, and the coastline is very uneven.
What would be the best way to calculate the distances for all these grid points?