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I am analysing data from a series of flood embankments which run parellel to a river. I have 80 KM of flood embankment and laserscanning data covering the area with 50cm resolution from which I have created a TIF DEM.

For a web-app project I am required to deliver a polyline and point feature class.These will show the highest points along the embankment with a distance of 10 meters between each point as well as a polyline showing the rigdge of the embankment parellel to the course of the river.

I have 3 methods which could work.

  1. digitize the ridge of the embankment per hand using aerial photos and then convert the polyline to points with a distance of 10 meters between each point. Using ArcGIS Spatial Analyst I could then extract height from the DEM and convert to Points.

The only problem with this method is that if I miss the summit of the line, I am not extracting the highest value.

  1. An alternative workflow would be to use the polyline which estimates the ridge of the embankment and convert to points with distance of 10m between each point. Then using ETGeowizards, create "station lines" (ie a perpendicular line with its center on each point. Using Spatial analyst again, I could then extract the highest value along each station line and thus determine the summit value.

  2. The third method would be along the lines of the folowing thread.(How do you identify ridges on an elevation raster?). This defines the ridge using ArcGIS focal-statistics and the raster calculator. My problem here is the fact that the result is not a point file.

Could anyone point to a better solution or advise me on which method to follow using the ArcGIS Platform?

Robert Buckley
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1 Answers1

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Use hillshade image of dem as background.

With few clicks draw draft of levee

Draw perpendiculars of reasonable length at small step along the line

Define highest point on the section

Draw minimum spanning tree of all points

Define shortest path between first and last points, this is your ridge line.

This was a method I used in Python script. It took 3 days for 2 technicians to successfully delineate 100s km of levees in Australia.

FelixIP
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