I have a client in the forestry sector that would like me to run some maps with criteria that I’ve never managed for. These maps will delineate (using polygons) areas of slope (0-20%,20-40%,>40%), distance from road centreline (0-125m, 125-250m, 250-350m, >350m) and “adverse” and “favourable” skids for a given “block area”.

The slope polys and distance buffers are easy enough to produce; I do this all the time.

The challenge for me will be figuring out how to identify the skid conditions. To give more insight on that, a “favourable” skid is defined as an area where harvested wood will be moved “downhill” to a road for decking. An “adverse” skid would be an area where the machine has to skid wood uphill. So this ultimately comes down to the location of the road, the +/- condition of the slope, and the aspect of the slope relative to the road. It’s a fairly complex condition to analyze, but I’m sure it can be done. My client is asking me to replicate another GIS contractor’s version of this product… which I am fairly certain is generated with some sort of model or script.

Has anyone done anything similar, or have any insight on how I could achieve these results?

I am running ArcGIS 10.3 and use anything from 1m-20m DEM and LiDAR datasets, but each block has its own constraints.

  • 1
    Have you looked at the Slope tool? Or are you needing a more specific approach? – Barbarossa Sep 12 '17 at 17:33
  • Hi. Yes the slope tool is what I use to generate a slope raster which I convert in to classified polygons to highlight areas. The question is, from these areas, I need to identify which ones will be positive or negative in relation to their closest road (lets say in a 300m buffer). Obviously all slopes are either positive or negative, but this analysis needs to take lines of force (for lack of a better term) in to consideration. – dufflayer Sep 12 '17 at 18:28
  • Delineate road catchment, or perhaps try road segments subcatchments using hydrology tools. Anything within catchment is good for skid – FelixIP Sep 12 '17 at 19:23
  • Can you elaborate. I am not too familiar with hydrology tools... I`m not trying to identify areas that are good for skid. Instead, I need to identify areas that are either adverse or favourable. – dufflayer Sep 12 '17 at 19:31
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    This has been answered here gis.stackexchange.com/questions/250259/… – GBG Sep 12 '17 at 23:23