For a given local neighborhood with center location s c and size k, we place a bonus or penalty^i0h(1 Á 2d i /r) on each location s i , where d i is that location's distance from the center, r is the neighborhood radius and h is a constant representing the strength of the compactness constraint. Each^i can be interpreted as the prior log-odds that s i will be affected, and thus the center location (d i 00,^i 0h) is e h times as likely as its (k ( 1)th nearest neighbor (d i 0r,^i0(h). We demonstrate that the penalized score function F'(S) 0F(S)'Ss i # S^i can be efficiently maximized over all subsets S for each neighborhood.