A Visual Corridor Analysis for Coastal British Columbia

Visual impact assessment is mainly concerned with the direct effect of development upon views of the landscape through intrusion or obstruction and the reactions of viewers who may be affected. The Ministry of Agriculture and Lands created a visual corridor analysis to assess the landscape that can be viewed from coastal ferry routes. Also used by the cruise ship industry, these routes were turned into observation points spaced every two kilometers. ArcGIS Spatial Analyst was used to run the viewshed based on these points. To create a viewshed for the entire route, four smaller viewshed grids were created and merged back together to create one seamless grid.

The 3D models on the map were created in ArcScene using a 1:20,000 scale DEM that was resampled from 25-meter to 100-meter grids. ArcGIS Spatial Analyst was used to run a viewshed using only one observation point. The resultant viewshed (colored red) was draped over a hillshade to create the scene. Approaching the observation point at water level, the landscape turns red as everything becomes visible. In the next two scenes the model is tilted to show where the landscape has to be protected to maintain a pristine coastline.

Courtesy of Doug Fetherston and the Province of British Columbia.