Viewshed

Viewshed calculates a 'viewshed' over Grid Items.

Select Analysis > Grids > Viewshed.

A Viewshed is the area that can be seen from a particular 3D location. For example, you could calculate a viewshed to determine how many residents in an area would be able to see a proposed wind generator. SIS Desktop 9.1 can calculate viewsheds for Digital Terrain Models (DTM) or grid items.

To create a viewshed:

  1. Select a DTM or Grid item.
  2. Select Viewshed.
  3. Click the location for the viewpoint in the map window.
  4. Complete the Create Viewshed dialog entries as follows:

    5. Option Description
    Height above ground The height above the snapped point from which to calculate the Viewshed.
    Radius The radius of the viewshed.
    Create as Grid The result of the Viewshed calculation will be one Grid item for each of the source Grid items.
    Create as QZone The result of the Viewshed calculation will be a single QZone item.
    Add origin Point item Check the tickbox to create a Point item at the origin of the Viewshed.
  5. Click OK to create the Viewshed item.