Using this option, you can manually enter an (X,Y) coordinate of the viewshed origin and calculate the line of sight from that point.
- Select Single Point from the Viewshed Origin drop-down list.
- Type the X and Y positions of the viewshed origin in the X and Y fields respectively.
- Type the height of the viewpoint, for example, a transmission or a fire observation tower, in the View Point Height field.
- Type the height of the object that is being viewed in the Terrain Offset field.
- In the Viewshed Radius field, type the maximum radius around the viewpoint to calculate the viewshed.
- Apply a suitable earth curvature correction to allow the scaling of the earth’s radius to the correct units. Select a correction from the Earth Curvature drop-down list. Refer to Viewshed Dialog Box for more details.
- Select the grid unit from the Units drop-down list.