1. A computer-implemented method of determining semantic place data, the method comprising: receiving, by a computing system and from a plurality of different mobile computing devices, a plurality of location sensor time series; partitioning, by the computing system, the plurality of location sensor time series into a plurality of localized segments, each localized segment of the plurality of localized segments corresponding to a time when a mobile device of the plurality of different mobile devices stayed within a given localized area; characterizing, by the computing system, each localized segment of the plurality of localized segments as belonging to one or more geographic region buckets of a plurality of different geographic region buckets; identifying, by the computing system, a plurality of clustering canopies, wherein identifying the plurality of clustering canopies comprises identifying, for each geographic region bucket of the plurality of different geographic region buckets, one or more clustering canopies; determining, by the computing system, a set of overlap scores, wherein determining the set of overlap scores comprises determining, for each group of localized segments of the plurality of localized segments that shares at least one clustering canopy of the plurality of clustering canopies an overlap score that correlates with an overlap among geographic regions covered by movement of one or more mobile computing devices of the plurality of different mobile computing devices associated with one or more localized segments of the plurality of localized segments in the group; generating, by the computing system and based on the set of overlap scores, a data structure that provides a hierarchical clustering of one or more localized segments of the plurality of localized segments in each geographic region bucket of the plurality of different geographic region buckets; and determining, by the computing system and based on the data structure, semantic place data for one or more localized segments of the plurality of localized segments.