Safety Assessment and Risk Estimation for Unmanned Aerial Vehicles Operating in National Airspace System

Table 2

Percentage of different types of areas and central angles.

Zone No.	Buildings	Trees	Sparse Tree	No Obstacles	Central Angle
Zone 1	17.32%	21.37%	23.74%	37.57%	78.0°
Zone 2	0	58.32%	32.39%	9.29%	26.2°
Zone 3	27.27%	49.69%	5.81%	17.23%	88.7°
Zone 4	0	41.95%	21.10%	36.95%	23.6°
Zone 5	11.14%	46.45%	6.68%	35.73%	87.0°
Zone 6	0	7.69%	62.03%	30.28%	56.5°