Qualitative Analysis Of Three-dimensional Spatial Relations

At present, more and more users have not resigned to the completion of a simple graphical query, graphics and other functions. More projects require powerful GIS analysis ability so that the developed systems will provide accurate and timely decision-support for managers. However, the existing GIS study is only the spatial information and attribute data for a simple operation. It's lack of analytical reasoning and effective access for spatial relations and so on; GIS industry widely recognized that the lack of analysis and modeling capabilities is currently a major flaw of space systems. Spatial analysis and spatial modeling technique can make up for GIS deficiencies currently to complete the important functions for decision- support. Support complex spatial analysis technology is the core objective of the GIS, but also one of the characteristics which is different from the other of information systems.GIS deal with the data related to the Earth, known as spatial data. Essentially, it's three-dimensional continuous distribution. At present, the GIS software available on the market mostly based on two-dimension or two and a half dimension (that is, three-dimensional surface) that they can not establish the spatial entities three-dimensional space relation, so the true three-dimensional operation is difficult to achieve.Spatial relations include topological relations, direction relations, distance relations. According to the content of the study, spatial analysis generally includes the characterization of spatial relations and qualitative reasoning. In the past ,the characterization of spatial relations and reasoning research mainly focused on two-dimensional spatial relations. It refers to the study of three-dimensional spatial relations rarely. This paper carries out the study of qualitative analysis theory of three-dimensional spatial relations. Therefore, this paper carried out the study for three-dimensional analysis of the relationship and modeling.What this paper has done as follows:1) The Cobb topological description is extended to three-dimensional space, putting forward using the characterization of triple-D topological relationship, and making a detailed study to three-dimensional topological relations qualitative reasoning.2) The three-dimensional space zoning model is introduced, raising that using a three-dimensional qualitative to describe three-dimensional orientation of triple relations; The three-dimensional direction of inference is divided into one-way and several ways relationship reasoning. Making a detailed study for one-way relationship reasoning and analyzing the links between one-way relationship reasoning and several ways relationship reasoning.3) The topological relations and orientation relations are two aspects of the relationship between spatial objects we described. There exists both topological relations and direction relationship between objectives and such two kinds of relations are not fully independent. The direction relationship implies a certain topological relationship and topological relations restricts the direction relations also. This paper made a detailed study to the derivation between topological relations and direction relations.4) Using the Euclidean distance between two spatial objects mass as a measure between two spatial objects, depending on the target object and reference object distance, the space segment is divided into five intervals and they were very close, close, intermediate, far, far away, with the logo q0 , q1 , q2 , q3 ,q4 , as described the characterized distance between two spatial objects . According to the three constraints of the distance, exporting the general formula of the qualitative reasoning results of the qualitative distance between orientation relationship and the anti-orientation relationships. For any direction of qualitative distance reasoning, it will introduce the combination of reasoning between the relationship between the direction relationship and distance relationship .5) The topological relations is only used to study the topological properties of space objects ,and is not conducive to identifying relationship between the target object and point of reference position . However, when the relationship between the target object and point of reference is known, it greatly enhanced ability to place a description of the direction relationship. This chapter describes of the direction relationship between the target and the orientation together with topological relations and location relations .it referred to as an integrated topology. Topological relations Comprehensive description refers to the methods to using topological relations and location relationship to describe co-location together between the objects . This paper describe the topological relationship between the objects with a dual group (t op , dir )( top∈( disjo int, meet , overlap ,cov er , contain, cov eredby , inside, equal). The dual Group has the advantage of describing the form of an intuitive response to topological relations and orientation relations between two spatial objects with a common description of the relationship between the location, but it is not suitable for qualitative reasoning. The paper choose the Allen interval which is suitable for qualitative reasoning to describe the intermediate form as described in the form of qualitative reasoning; it deeply study Allen interval about the description to topological relationship t, and discussed in detail about the Swap operations in Allen interval's description form and the dual group description form . On this basis, it studied deeply about qualitative reasoning of the topological direction relationship.6) In three-dimensional space, using the projection direction which have established the position relationship to describe model. Using a dual group ( dis , dirab),dis∈{q0,q1,q2,q3,q4},dir_ab= (dirab_x,dirab_y,dirab_z),dir_{ab x}∈{west,between, east},dir_{ab y}∈{s outh, between, north}, dir_{ab z}∈{d own , between, up}describe the location relationship between the target B and the reference A. Depending on the location relationship between the target object B and the reference A and location relationship between target C and the reference B, the location relationship between C and reference A is derived.Qualitative analysis of the three-dimensional space relationship research is a cornerstone of intelligent three-dimensional GIS, and it will directly affect the structural organization of GIS spatial data, spatial query, spatial reasoning and the integrity and validity of spatial analysis so that the application of GIS is more efficient and convenient.