Department of Geography and Urban Studies, Temple University GUS 0265/0465 Applications in GIS/Geographic Data Analysis

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Department of Geography and Urban Studies, Temple
UniversityGUS 0265/0465Applications in
GIS/Geographic Data Analysis
Lecture 5 Terrain Analysis
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• Terrain Operations
• slope
• aspect (orientation)
• hillshade
• intervisibility

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• Digital Elevation Model (DEM)

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• Percent Slope Calculation

slopee
where
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slopee
10 m resolution
(7 2(5) 2) (3 2(2) 1)
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(7 2(5) 3) (2 2(1) 1)
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80
80
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slopee
10 m res


0.23

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• Aspect (orientation)

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• Aspect (orientation)

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• Hillshade

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• Intervisibility

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• Intervisibility

observer
DEM
Visibility
0
1
Elevation in meters resolution 100 meters
Is there a higher elevation between observer and
each cell?
0 not visible 1 visible
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• Hydrologic Modeling
• Fill Sinks
• Eliminate pits in the DEM
• Flow Direction
• cell value indicates the direction of flow from a
  given cell
• Flow Accumulation
• cell value indicates the number of cells flowing
  into a given cell
• Stream Delineation
• cell value indicates whether a cell is a stream
• Watershed Delineation
• cell value indicates whether a cell is within an
  upslope contributing area of a given cell

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• Fill Sinks

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• Flow Direction

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• Flow Accumulation

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• Stream Delineation
• Selects cells above a certain threshold flow
  accumulation value

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• Basin Delineation

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• Watershed Delineation