  This paper presents an alternate choice of computing the convex hulls (CHs)
for planar point sets. We firstly discard the interior points and then sort the
remaining vertices by x- / y- coordinates separately, and later create a group
ofquadrilaterals (e-Quads) recursively according to the sequences ofthe sorted
lists of points. Finally, the desired CH is built based on a simple polygon
derived from all e-Quads. Besides the preprocessing for original planar point
sets, this algorithm has another mechanism of discarding interior point when
form e-Quads and assemble the simple polygon. Compared with three popular CH
algorithms, the proposed algorithm can generate CHs faster thanthe three but
has a penalty in space cost.
