Thelocationof a displaced person camp may range from a spontaneous settlement over awide area, to an organizedruralsettlement, to a concentration ina verylimitedarea.
While these systems offer a number of advantages for time-critical two-way communications, they are expensive and limited if you need wide-area coverage, especially across a country or continent.
Scanning over a widearea, though, is challenging because of the amount of territory that must be reviewed, the limited field of view of the human eye, and the effects of fatigue.