DBLOC: Density Based Clustering over LOCation Based Services.

Location Based Services (LBS) have become extremely popular over the past decade. Popular LBS run the entire gamut from mapping services (such as Google Maps) to restaurants reviews (such as Yelp) and real-estate search (such as Zillow). The backend database of these applications can be a rich data source for geospatial and commercial information such as Point-Of-Interest (POI) locations, reviews, ratings, user geo-distributions, etc. However, access to the backend database is often restricted by a public query interface (often web-based) provided by the LBS owners. In most cases the public search interface of these applications can be abstractly modeled as kNN interface, taking a geolocation (i.e., latitude and longitude) as input and returning top-k POI's that are closest to the query point, where k is a small constant such as 50 or 100. Because of this restriction it becomes extremely difficult for third-party users to perform analytics or mining over LBS. We demonstrate DBLOC, a web-based system that enables analytics over the LBS by using nothing but limited access to kNN interface provided by the LBS. Specifically, using DBLOC the users can perform density based clustering over the backend database of LBS. Due to query rate limit constraint - i.e., maximum number of kNN queries a user/IP address can issue over a specific period of time, it is often impossible to access all the tuples in backend database of an LBS. Thus, DBLOC aims to mine from the LBS a cluster assignment function f(.), such that for any tuple t in the database (which may or may not have been accessed), f(.) can produce the cluster assignment of t with high accuracy. We also demonstrate how DBLOC enables the users to further analyze the discovered clusters in order to mine interesting intra/inter cluster information.