How to consider the direction in calculating distances

Discussion created by gislearner1 on May 16, 2014
Latest reply on May 19, 2014 by gislearner1

As part of a research project that requires mapping of relevant landscape elements with respect to water flow of nitrogen from agricultural sources (ANR ESCAPE project), I try to build a layer of distance to relevant landscape elements in the studied watershed. To be relevant, a landscape element must be downstream with respect to the runoff direction.

Clearly, I want to assign to each point belonging to a regularly spaced points layer,  the distance to the nearest LANDSCAPE ELEMENT which is in the direction of the slope.

To do so, I have :
A polygon shapefile of «*LANDSCAPE ELEMENTS*» which are polygons of hedgerows, and forests (that are not distinguished).
A Digital Elevation Layer 25 m (from IGN France)
A shapefile of a regular point grid (50 mx 50 m, a total of 500 000 points )

For now, I have managed to calculate a layer of distances from the nearest LANDSCAPE ELEMENT without taking into account the direction.

Could anyone tell me how should I proceed to consider the direction in calculating distances ?

I???m using ArcGIS 10.1 with Spatial Analyst

Thank you in advance