  Compared with the traditional spherical harmonics, the spherical needlets are
a new generation of spherical wavelets that possess several attractive
properties. Their double localization in both spatial and frequency domains
empowers them to easily and sparsely represent functions with small spatial
scale features. This paper is divided into two parts. First, it reviews the
spherical harmonics and discusses their limitations in representing functions
with small spatial scale features. To overcome the limitations, it introduces
the spherical needlets and their attractive properties. In the second part of
the paper, a Matlab package for the spherical needlets is presented. The
properties of the spherical needlets are demonstrated by several examples using
the package.
