Using ModelBuilder Landslide Susceptibility

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Using ModelBuilder Landslide Susceptibility

• Ann Johnson
• TRESTE - 2006

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Modeling Landslides

• What factors influence landslides?
• What data can be used to model landslides
  susceptibility and what are we going to use?
• What analyses can suggest probabilities of
  landslides?
• What is ModelBuilder and how can it be used to
  model landslides
• How can the results be visualized in 3D

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Landslide Susceptibility steep mountain slopes,
faults, climate
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Add Fires
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3D View of burned area
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Factors Influencing Landslide Susceptibility

• Slope steeper more susceptible
• Aspect South facing dry, little vegetation
• Burn Severity least vegetation as severity of
  burn increases and creating hydrophobic soil
• Weigh each outputs affect to determine areas
  with highest susceptability

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Our Analysis Will Use

• Raster
• pixels
• a location and value
• Elevation of study area
• hIllshade of elevation
• DRG of study area
• Vector
• Lines Polygons
• Features
• Roads, Streams, Faults, geology, burn severity

Real world
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Basic Data Sets for Our Model

• Raster
• Elevation data (DEM)
• Continuous data set with each center of a grid
  containing the value for the elevation (10 x 10 m
  grid, Z in meters)
• Digital Raster Graphic of study area
• Vector
• Severity of burn
• Road, streams, faults, geology, historic
  landslides
• Vector to Raster Conversion
• Severity of burn from Vector (polygon) to raster

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Faults Layer
Streams Layer
Landslide Layer
Roads Layer
DEM Layer
Four Vector and One Grid Data Layers
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DEM - Raster
Properties of elevation layer
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Geology Old Slides
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Grids Layers can be Combined - binary
suitability models

• Use for simple problems
• Map Algebra or Boolean And Tools
• Classify layers into good (1) and bad (0)
• Combine with AND, addition or multiplication
• ski snow slope sun
• Advantages
• Easy
• Disadvantages
• No nextbest sites
• All layers have same importance
• All good values have same importance

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Using Tools in ArcToolbox one by one
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Spatial Analyst gt Surface gt Hillshade To shade
and make elevation look 3D
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Spatial Analyst gt Surface gt Slope To determine
slope from elevation
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Spatial Analyst gt Reclass gt Reclassify gt Slope To
determine the Angles of the Slope
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Conversion gt To Raster gt Feature to Raster To
Convert burn Polygon to Raster
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Weighted suitability models

• Use for complex problems
• Overlay tool from Spatial Analysis Toolbox
• Classify layers into suitability 1-9 (9 best)
• Weight and add together
• Ski (snow .5) (slope .3)
  (sun .2)
• Advantages
• All values have relative importance
• All layers have relative importance
• Returns suitability on a scale 1-9
• Disadvantages
• Preference assessment is harder

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Spatial Analyst gt Overlay gt Weighted Overlay To
use relclassified Slope, Aspect, and Burn
Severity datasets and weigh effect of Slope most
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Finals Output Possible Slide Areas
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Automating Analysis ModelBuilder
. . . And Shared
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Landslide ModelBuilder
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3-D Analyst ArcScene
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www.geodata.gov, http//seamless.usgs.gov/
http//www.census.gov/geo/www/tiger/
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Hands On all work together

• Use Handout
• Introduce data and ArcCatalog
• Look at a Landslide data sets
• Use ModelBuilder and build a Model
• Use results and create an ArcScene project and
  create a fly through animation
• If you know GIS and want to go ahead, you can do
  them on your own

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Lets have fun!

• Angela Lee alee_at_esri.com
• Ann Johnson - ajohnson_at_esri.com