The notion of "antimatroid with repetition" was conceived by Bjorner, Lovasz and Shor in 1991 as a multiset extension of the notion of antimatroid . When the underlying set consists of only two elements, such two-dimensional antimatroids correspond to point sets in the plane. In this research we concentrate on efficient representation of antimatroidal point sets. We define a set of corner points that concisely represents a given antimatroidal point set and show how to reconstruct the antimatroidal point set from a proper set of corner points. We also present an algorithm allowing the given set of points to be recognized as a set of corner points of some antimatroidal point set.