Left panel: interval probability function, ipf, φ(A) = ProbA/c ≤ area < Ac, c² = 1.5, found with the RGO database for all groups observed on any day (snapshot distribution), for maximal observed areas of all groups (max1), and for those whose maximal area is observed at longitudes l_E ∈ [60,120] in coordinates associated with Earth observers (max2). Right panel: enlargement of the rectangular window in left part of the figure ( μH are millionths of a solar hemisphere).