# Cost Path Analysis of Skid Trails Using GIS

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```					Cost Path Analysis of Skid
Trails Using GIS

Laura Heath
December 14, 2006
FOR 557
Outline
   Purpose
   Location
   Analysis Approach and Obstacles
   Results
Purpose
   Cost Distance Analysis
   Raster analysis that calculates the cost of traveling
from one cell to the next based on assumptions
specified by the user.
   Goal:
   Determine least cost paths for skid trails in logging
operations.
Best Management Practices
   Limit the crossing of streams
   No cutting within a 50 ft. buffer around streams and
bodies of water
   Skid trail distances from water:
   50 ft with slope <10%
   100 ft with slope >10% and <30%
   150 ft with slope > 30%
   Landings should be flat and well-drained
   Use existing roads/trails as much as possible
Approach
   Obtain necessary information:
   Roads
   Tax parcels
   DEMs
   Hydrography
   Edit data to match with orthophotos

Vector           Raster
Data             Data

Vector            Raster        Cost      Cost      Cost
Data              Data        Surface   Distance   Path

Vector            Raster
Data              Data
Location        Sexsmith Lake in
Davenport, NY

®

Delaware                          trails
roads
County                           lake
river
harvest blocks
Step 1: Find location of landing

   Slope ≤ 3%
   Within 100 meters of road
   Intersecting the road
   Not within 50 meters of a
body of water
   Located within the harvest
stands
Step 2: Erase
Hydrography Buffers from   Step 3: Convert DEM to
Harvest Stands         Percent Slope Classes

blue: >30%      pink: 10-30%
purple: 5-10%   green: <5%
Step 4: Create Concentric Polygons Within
Harvested Stands
Step 4: Create Concentric Polygons Within
Harvested Stands
Step 5: Convert to Raster

   Spatial Analyst Toolbar → Convert → Features to Raster
 Slope (%)

 Concentric polygons (distance from edge)
 Roads (ID of 1)
Step 6: Reclassify
   Change values of cells to reflect cost of travel
   Concentric polygons:
   -300 → 1
   -250 → 2
   -200 → 3
   -150 → 4
   -100 → 5
   -50 → 6
   NoData → 7

   Slope:
   0-5% → 1
   5-10% → 2
   10-30 → 5
   >30% → 10
   Road:
   ID 1 → 1
   NoData → 50
Step 7: Overlay Rasters to Create the Cost
Surface
   GIS Help says to use
Weighted Overlay Tool

   I used the Raster Calculator in
Spatial Analyst

[concentric polygon] + [slope] + [roads]
Cost Surface

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Step 8: Create Cost Distance Raster

   The cost raster was created using the cost
distance tool
Cost Distance Raster
Step 9: Cost Path

   Calculates most efficient pathway given a destination, cost
distance raster and cost backlink raster.
Results
Questions?

```
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