[GIS] Upslope and downslope distance or area using ArcGIS Desktop

arcgis-desktopnetwork-analystraster-calculatorroadspatial-analyst

Is there a possibility to determine the surface area above the road and the surface of the terrain below the road or between two or more roads? I want to pull the trees down the hill and up the hill to the roads. The price of skidding trees is different so I would like to know what the surface (ha) is above and below the road?

Here is an example, orange is uphill and red is downhill.
I think this is solved with a raster calculator

Here is the method, but I do not know how to solve it in ArcGIS Desktop

Best Answer

In ArcGIS, convert the road to a raster using Polyline to Raster. Using your surface model create a flow direction raster using the Spatial Analyst Hydrology tools. Use the flow direction raster and the rasterized road to generate a watershed using the Watershed tool. The resulting watershed will be all the areas that are uphill of the road.

Related Solutions

[GIS] What does the code RTTYP represent in the USA Tiger road files

I found this metadata file indicating:

C = County
I = Interstate
M = Common Name
O = Other
S = State recognized
U = U.S.

[GIS] Road design using Least cost path by longitudinal slope in ArcGIS Desktop

Connecting 2 points on contours by straight line is not going to work, as seen on your second picture line crosses same contour twice. I also very much doubt that any out of the box tools can help you. You'll need to invest heavily in scripting.

Funny enough people in the past were able to solve this task by tracing footsteps of heavily loaded donkey. Smart and laizy (or other way around) animal is able to pick the most efficient = same gradient = path on it's way home. This is why I called relevant tool DonkeyTheDesigner. I applied it on subset of your contours and after 3 iterations found that 1:33 gradient is the best option to go between 2 points shown:

I am not willing to share the code for free but general workflow is as follows:

define the direction of route by flipping when necessary contours of interest towards higher point. Without this there are infinite number of solutions to reach upper contour from lower, e.g. zig-zag
Connect vertices of contours using triangulation. Remove horizontal connections and flip ones that head downhill.
Assume linear change of elevation between contours along connections
Take the start point of connection nearest to source point and find point on next connection towards destination with matching grade.
Continue untill number of next connections equal zero.

Picture below explains algorithm and also shows line manually drawn by you, - RULE:

Yes, my donkey is climbing ...

Best Answer

Related Solutions

[GIS] What does the code RTTYP represent in the USA Tiger road files

[GIS] Road design using Least cost path by longitudinal slope in ArcGIS Desktop

Related Question