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Step By Step. Step 1 Building Base Data. Concern. Determine Concern 3 levels, based on number of viewers and area attributes. Route system usually provides the base. Concern Level 1. State and Federal Highways Wild/Scenic Rivers - PowerPoint PPT Presentation
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Step By Step
Step 1Building Base Data
Concern• Determine
Concern• 3 levels, based
on number of viewers and area attributes.
• Route system usually provides the base.
Concern Level 1
• State and Federal Highways
• Wild/Scenic Rivers• Forest Highways,
Scenic Byways and major recreation sites & access
Concern Level 2
• County Roads• Wilderness and
wilderness access trails
• Other scenic routes
Concern Level 3
• Other Forest Roads
Prepare Concern• Buffer Project
Area• Clip Concern
Layer• Separate
Concern by levels
12 m
iles
Build Surface
• Clip Elevation• Calculate
roughness to use as impedance
Step 2
Build View Zones
Distance Zones
Adding Topography
Cost Distance• Using the
impedance raster compute the cost distance for each of the concern layers.
Concern level 1• Calculate• Reclassify into
zonesFG1
MG1
BG1
Concern level 2• Calculate• Reclassify into
zones
FG1
MG1BG1
Concern level 3• Calculate• Reclassify into
zonesFG1
MG1
BG1
Step 3
Build View Points
Create Fishnet• Create 1 km
Fishnet using XTools
Build Level 1 points• Combine fishnet
with concern 1 routes using ‘Feature to Line’ tool.
• Delete Fishnet (concern = 0)
• Convert segments to points with ‘Feature to Point’ tool
Repeat for level 2• Combine fishnet
with concern 2 routes using ‘Feature to Line’ tool.
• Delete Fishnet (concern = 0)
• Convert segments to points with ‘Feature to Point’ tool
And again for level 3• Combine fishnet
with concern 2 routes using ‘Feature to Line’ tool.
• Delete Fishnet (concern = 0)
• Convert segments to points with ‘Feature to Point’ tool
Group for Processing• Subdivide
viewpoints into groups of 200-300 points.
• Use buffered clips of elevation, based on the zones.
Viewsheds: Level 1• Calculate
viewsheds for each zone.
Viewsheds: Level 2• Repeat modeling
for Concern Level 2 points, by each zone
Viewsheds: Level 3• And again,
model viewsheds for the concern level 3 points, by zone.
Combine Viewsheds• Combine
viewsheds for each concern level using MAXIMUM method
Step 4
Combine view zones with viewsheds.
• Use Viewshed to mask Zones
• Unmask Foreground
• Redraw Zones
Masking Viewsheds
Level 1 Viewsheds• Extract
Foreground Zone• Set up not seen
area mask for concern level
• Mask middle and background zones
FG1
MG1
MG1
BG1
BG1
Not seen
Level 2 Viewsheds• Extract
Foreground 2 Zone
• Set up not seen area mask for concern level
• Mask middle and background zones
FG2
MG2
MG2
BG2Not seen
Level 3 Viewsheds• Extract
Foreground 3 Zone
• Set up not seen area mask for concern level
• Mask middle and background zones
FG3
MG3
MG3
BG3
Not seen
Putting it together• Combine the
resulting rasters
Final Processing• Convert to
polygons• Classify grid
values and dissolve
• Eliminate zones less than 100 acres
• Clip to boundary
A Closer Look
References• Landscape
Aesthetics- Agriculture Handbook 701
• ESRI Spatial Analyst Help Files
USFS-2010 David C. McMorran
•Step By Step