# Viewshed

## Types

## Properties

The horizontal angle of the observer's field of vision. Visible and non-visible areas are determined for an area defined by an observer location, horizontal and vertical view angles, and a minimum/maximum distance range. These properties define a frustum (3D solid) inside of which visibility is calculated. The horizontal angle must be greater than zero to define a valid frustum and is constrained to a maximum of 360 degrees.

The minimum distance from the observer at which visibility will be evaluated. The minimum distance allows you to exclude obstacles close to the observer (the corner of a building, for example). Since terrain and other obstacles between the observer and the specified minimum distance are completely excluded from the analysis, this value should be relatively small.

The vertical angle of the observer's field of vision. Visible and non-visible areas are determined for an area defined by an observer location, horizontal and vertical view angles, and a minimum/maximum distance range. These properties define a frustum (3D solid) inside of which visibility is calculated. The vertical angle must be greater than zero to define a valid frustum and is constrained to a maximum of 360 degrees.