In the visualization, 

Macopt-gorilla
Brown squares are the coverage disks at expected coverage maximizers
Yellow points [0,1,2] are the locations of highest uncertainty, where the agents go there for density observations
Black lines are constraints, but they are not active since it is an unconstrained environment for MacOpt

SafeMac-obstacles.mp4, SafeMac-gorilla.mp4
Black dots denote the pessimistic set, 
Yellow dots represent the optimistic set, 
Brown circles are the agent's location, 
Brown squares are the set coverage disks at expected coverage maximizers,
The red stars denote the locations of collected samples
Black lines are the obstacles constraints and the cloud constraints, respectively, for both the videos
The disks change shape in visualization since we plot it on the safe region only, and 
near the edge, when it is unsafe, agents do not cover, and the coverable area (disks) shrinks in the visuals

