Calculating the slope of a hiking trail

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03-09-2012 11:09 AM
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TimothyHales
Esri Notable Contributor
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Trail hiking can be a fun and exciting activity when you properly prepare for the hike.  An important step for preparation is knowing the trail.  Some key factors include: length, minimum elevation, maximum elevation, and slope.  If you do not have a trail information guide, you can easily calculate this information with ArcGIS for Desktop.First you must gather a polyline file for the trail and an elevation raster for the area of interest.Add-Surface-Information-MXD.jpg

3DToolbox.jpgThen use the Add Surface Information Tool which is found in the 3D Analyst Toolbox.

This tool takes the input surface and interpolates the heights for the features by converting them to 3D in the background.  It then calculates the 3D properties for these features and writes the property values as attributes to the input feature class.

From the Add Surface Information tool dialog input these required parameters:
  • Input Feature Class: Hiking Trail Polyline Layer
  • Input Surface: Elevation Raster
  • Output Property: Select desired properties to be calculated
AddSurfaceInformationTool.jpg

Once the Add Surface Information tool completes the calculation process, the selected Output Properties are appended to the input feature table.ProcessedTable1.jpg

With this information you are now able to properly plan your hiking trip.  In addition to this hiking example, there are a several other applications for this concept such as for use with bike paths, pipelines, streets, and drainage areas.Timothy H. – Raster/3D Support Analyst
4 Comments
MaxwellSeebeck
New Contributor

Timothy,

I am getting some really high slope average values (Table attached). I have a pretty high resolution DEM and a polyline feature that was converted from a KML. Any idea on why I am getting an average slope of 9999 - 10000? Projection maybe?

MaxwellSeebeck
New Contributor

Figured it out. Wasn't projected

GiovanniVanore1
New Contributor II

Yes, the documentation says that the slope values for line features are calculated as a percent, or grade, for each line segment, but how can I understand if the values that I'm seeing in the table are percent or grade?

YujiaZhang
New Contributor

@MaxwellSeebeck @TimothyHales  Did you guys know how to fix the problem that @MaxwellSeebeck mentioned? This happens to me too, the slop value is between 9999-10000. I wonder id this has something to do with the unit settings of add surface information?

About the Author
Timothy Hales is a Senior Education Specialist for Esri Training Services developing instructor-led and web courses. Before developing training content for Training Services, he was the Enterprise Community Manager for Esri Community (GeoNet).