Research Of Spatial Retireval Based On Real Objects Model

With the developments of the spatial database technology and geographic information systems, the study on the real objects has rereceived more and more attentions then ever to face the reality of life in a variety of things. Based on the model of the real objects direction relation, and for the purposes of searching spatial objects, all the necessary components on the retieval of spatial objects are studied after depth analysis of the current home and abroad situation in this thesis.Firstly, at the beginning of the direction relation models, the advantages and disadvantages of many kinds of direction relation models are analyzed and discussed. Then, on this basis the direction relation model is extended through a series of definations and theorems, so that it can better adapt the complex characteristics of real objects.Secondly, based on the expansion of real object direction relation model, we analysis the theory of synthesis. For the problems that the theory can't handle the situation when the objects are on the boundaries of the direction relation region and on the cross-point of the direction realtion region and can not applicable the models, which are established by point-type reference and line-type reference, a new synthesis algorithm is proposed. Then to the algorithm, the example analysis and experimental verification are given.Finally, based on above direction relation model, the steps of retrieval on spatial objects are given. To improve the retrieval accuracy of spatial objects, combination of deep direction relation matrix, the R*-tree index structure is improved.Then, against the index structure, the corresponding search algorithm and the evaluation of retrieval precision rates are given. According to precision rate, compared to the traditional R*-tree index structure, the correctionding experiment is conducted.