I have a set of points and I'd like to be able to find the nearest point from another layer. The problem is that I need to find the closest point without crossing an obstacle (such as a river, highway, etc). Any idea how to do this?
The solution to this will depend on whether you want to work with vector data and have access to the Network Analyst extension or raster data and have access to the Spatial Analyst extension.
If you use Network Analyst and its Shortest Path then just put Barriers on any river/highway crossings.
If you use Spatial Analyst and its least-cost path then put a high cost on crossing rivers/highways.