Extract elevation of ridge crest of a mountain range

DavidWampler

I'm trying to find the best way to do this.

I started by just placing points 1km apart on the highest point of the DEM for the mountain range, using an aspect map to easily see where the slope shifts. It worked pretty well for much of the range since the highest point is easy to determine. My plans were to then link up these points into a series of 1km polylines to analyze.

It wasn't a perfect solution, but because much of the mountain range is very simple, it was workable. However, part of the mountain range has no clear single crest, and instead has a series of peaks. How to "draw" the crest between peaks isn't obvious.

What I would like to do is draw a rough line parallel to the general trend of the mountain range, and then grab the highest DEM value orthogonal to each point of the line. This would easily give me something I would can feel confident calling the "ridge crest" of the mountain range, with less opportunity for human error than my current plan.

Is there a way to do this? A tool to look orthogonally from a line I draw, grab the highest value from a DEM in that direction, and attribute it to the line (or a new layer)? I haven't found any direct or indirect ways to do this from my searches.

Thanks a ton!

RobertBorchert

You could convert the dem to points.  it would give the points the value of each raster cell.  the end result would be the highest number indicates the highest point and so on. 


You could also play with the colors for the DEM.

If you open the layer properties and go to the symbology tab.

For example I have a DEM of the Black Hills near Custer.  The low end is 4095 and the high is 6031

select Classified and give it say 20 classifications.   It will break it so that each group contains roughly 5% of the total number of values.  In the Black Hills DEM the top group has a range of 293 feet.  The bottom one has 163  another in the middle has only 75 feet of elevation change.

If you hit the classify button you can then lengthen or narrow the range that would represent the ridge.  You can give it  distinct red color to really make it pop out. 

You then draw your line along the ridge.

I'm trying to find the best way to do this.

I started by just placing points 1km apart on the highest point of the DEM for the mountain range, using an aspect map to easily see where the slope shifts. It worked pretty well for much of the range since the highest point is easy to determine. My plans were to then link up these points into a series of 1km polylines to analyze.

It wasn't a perfect solution, but because much of the mountain range is very simple, it was workable. However, part of the mountain range has no clear single crest, and instead has a series of peaks. How to "draw" the crest between peaks isn't obvious.

What I would like to do is draw a rough line parallel to the general trend of the mountain range, and then grab the highest DEM value orthogonal to each point of the line. This would easily give me something I would can feel confident calling the "ridge crest" of the mountain range, with less opportunity for human error than my current plan.

Is there a way to do this? A tool to look orthogonally from a line I draw, grab the highest value from a DEM in that direction, and attribute it to the line (or a new layer)? I haven't found any direct or indirect ways to do this from my searches.

Thanks a ton!