Assume that a set of imprecise points is given, where each point is specified
by a region in which the point may lie. We study the problem of computing the
smallest and largest possible convex hulls, measured by length and by area. Generally
we assume the imprecision region to be a square, but we discuss the case where
it is a segment or circle as well. We give polynomial time algorithms for several
variants of this problem, ranging in running time from O(nlog n) to O(n13), and
prove NP-hardness for some other variants.