topic Re: Classify roads by slope in Transportation Questions

Classify roads by slope

ArthurVrechi — Tue, 11 Dec 2012 14:50:31 GMT

Hi everybody,

I have a road network database and I need to classify it by slope in classes (ie. 0-3%, 3-6%, >6%).
In order to do that, I have the contours (lines), the mass point for altimetry and I can generate a DEM or slope raster with this data.

But, as the slope value for each segment depends on the angle that the road segment will cross the terrain, it doesn't look like having a simple solution.

It could be possible if there is a way to assign, for each segment, the values of initial and end altittude, based on the contours (like when the roads cross the contours)....but I have no idea how to do that.

Any idea?

Thanks!

Arthur Vrechi

Re: Classify roads by slope

AndrewMoffitt — Tue, 11 Dec 2012 18:35:10 GMT

Hi everybody,

I have a road network database and I need to classify it by slope in classes (ie. 0-3%, 3-6%, >6%).
In order to do that, I have the contours (lines), the mass point for altimetry and I can generate a DEM or slope raster with this data.

But, as the slope value for each segment depends on the angle that the road segment will cross the terrain, it doesn't look like having a simple solution.

It could be possible if there is a way to assign, for each segment, the values of initial and end altittude, based on the contours (like when the roads cross the contours)....but I have no idea how to do that.

Any idea?

Thanks!

Arthur Vrechi

The way I envision this being solved is by using said generated DEM, buffering roads by either a real value or false approximate value, running zonal statistics (mean) with the roadID being the zone ID and joining the output table back to the road linear feature by the roadID. The grouping can be accomplished either via a manual select by attributes and then a field that holds the value or more automated in Model builder with a field calculation. Hope this rambling makes sense.

Re: Classify roads by slope

ArthurVrechi — Thu, 13 Dec 2012 11:26:20 GMT

Thanks Andrew!

It worked very well.

Now, I need to find a way to define if the slope is negative or positive dependig on my traffic direction, I guess I'll use two fields (one for each direction) for that.

Arthur