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 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 miles

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 zones FG1 MG1 BG1

Concern level 2 Calculate Reclassify into zones FG1 MG1 BG1

Concern level 3 Calculate Reclassify into zones FG1 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 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 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 BG2 Not seen

Level 3 Viewsheds Extract Foreground 3 Zone Set up not seen area mask for concern level Mask middle and background zones FG3 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. M c Morran

Step By Step