Step By Step

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