  Constructing partitions of colored points is a well-studied problem in
discrete and computational geometry. We study the problem of creating a
minimum-cardinality partition into monochromatic islands. Our input is a set
$S$ of $n$ points in the plane where each point has one of $k \geq 2$ colors. A
set of points is monochromatic if it contains points of only one color. An
island $I$ is a subset of $S$ such that $\mathcal{CH}(I) \cap S = I$, where
$\mathcal{CH}(I)$ denotes the convex hull of $I$. We identify an island with
its convex hull; therefore, a partition into islands has the additional
requirement that the convex hulls of the islands are pairwise-disjoint. We
present three greedy algorithms for constructing island partitions and analyze
their approximation ratios.
