  A filament is a high density, connected region in a point cloud. There are
several methods for estimating filaments but these methods do not provide any
measure of uncertainty. We give a definition for the uncertainty of estimated
filaments and we study statistical properties of the estimated filaments. We
show how to estimate the uncertainty measures and we construct confidence sets
based on a bootstrapping technique. We apply our methods to astronomy data and
earthquake data.

Methodology;Computational Geometry