A Research On Spatial Keyword Query Method Based On Collective Object

With the rapidly development of localization technology, services based on location has been widely used in mobile users currently. This leads to the incessant appearing of various mobile equipment with localization technology, location-based and text-based searching technologies are furthermore proposed. To meet this explosive searching requirements, many effective spatial keyword searching algorithms have been developed based on the searching conditions. These algorithms fall into three categories: single-objection-oriented,collection-oriented, collection and direction-oriented methods. And each category consists of distinct algorithms which deal with different searching condition or searching environment.The road network is the abstraction of people's living space,which has more practical importance and value. Collection and direction-oriented spatial keyword searching methods have not been proposed on road network problems. In this paper, a road network-based collection and direction-oriented spatial keyword effective searching method is proposed.First, the whole road network is divided into several connected local networks, and a spatial index is constructed based on the hierarchy structure of these local networks. The spatial index aims to rapidly skip the network that do not include these searching keywords and directly step into the next network including these keywords. Then the local networks are found based on the given searching direction and range. Finally, a route is formed to satisfy the limitations which list searching text and spatial location as well as the searching range.The route meets the following conditions: 1) the text of spatial object on the route is able to satisfy the searching text; 2) this rout is the most optimal, that means users can complete all the things that need to do through using this route and the cost of this rout is the least, which can be the distance of the route, the consuming time or the using money.In this paper, main keyword-oriented searching and no main keyword -oriented searching are presented aimed at the collection and direction-oriented spatial keyword searching on the road network. No center-oriented searching starts from the searching point and expands the search in the searchable range. During the center-oriented searching, spatial objects that can meet the main keyword are found in the searchable range firstly. Then the expanding search is conducted in the searchable network, which starts from the spatial object. Finally, experiments about the above two searching methods are conducted and the results show the efficiency of the algorithm.