The Study Of Integrated Modeling And Parallel Computing Method For Geographic Scene Based On Geometric Algebra

Nowadays, the research of geography is shifting towards the paradigm of systematic and big data, presenting the development characteristics of multi scale integration. As a method and technical support, Geographical Information System (GIS) should achieve the integrated modeling, simulation and analysis of different scale geographic system based on the accurate expression of the real world. However, the existing GIS methods based on Euclidean geometry and computational geometry are highly dependent on the coordinate system. Its operation and expression are lack of parametric and adaptive characteristics, so it's weak in integrated expression of geographic semantic, multi-scale spatial-temporal evolutionary process and element interaction and hard to directly support the expression and analysis demand of spatial-temporal big data. There, there is an urgent need to develop a new research model to integrate the multiple expression of discrete and continuous, concrete and abstract, geometry and algebra in real world. The new research model can be used to support structural parallel processing and realize the expression, modeling and comprehensive analysis of multi scale geographic scene and geographical law.In this paper, aiming at supporting geographic analysis and geographic computing,the geometric algebra theory is introduced to construct the integrated modeling theory and method system in geometric algebra of GIS geographic scene which is based on geographic scene model, characterized by space-time multidimensional fusion and using unified expression of multivector in geometric algebra as the core, seek the organization and storage method of multidimensional geographic data which is suitable for geographical scene computation and construct and optimize the arithmetic operators and algorithms library of multidimensional space computation based on geometric algebra operators. By constructing a unified multidimensional geometric algebra calculation space and separating, reorganizing and optimizing code of model layer, code layer, and operation layer, the calculation model of geometric algebra and spatial calculation template for different spatial computation are set up to realize the parallel computation of GIS spatial computation in geographic scene, so the applicability and computational efficiency of the existing space computation can be increased substantially. The main research results and contents are as follows:(1) The concept model of scene representation based on geometric algebra is constructed, and the concept and connotation of geographical scene are introduced, and the diversity of expression is expounded, and the six basic elements of the expression are summarized. The Characteristic subspace of typical Euclidean, homogeneous f conformal space and its connotation are concluded,and the spatial multidimensional hierarchical structure based on geometric algebra and multi element composite structure which fusing the information of geometry, semantics, relation and attribute are constructed. The spatial expression theory based on geometric algebra is discussed,and the theoretical basis of geometric algebra which contains concept of inner product,outer product and geometric product and its expression support for the geography scene are introduced, and on this basis the expression method of geography scene of geometric algebra is proposed. Under the support of above theoretical structure, the expression and analysis requirements of scene GIS are analyzed, and the related key technologies are summarized, and the overall structure of the GIS data model of scene GIS based on geometric algebra is constructed, and the multidimensional fusion expression feature based on multivector structure is expounded, and the multi element scene model based on geometric algebra is designed.(2) The realization and modeling method of scene model based on geometric algebra is designed, and the scene organization hierarchy mode of element expression,object expression and scene expression is constructed, and the geometric algebra expression method of vector, network and spatial-temporal field data is discussed, and the embedding method of event and state in the scene is designed from the object-oriented view. The multivector tree structure based on MVTree is designed, and the data traversal and operation method of MVTree is constructed, and the calculation of laying scene spatial relation is realized. The data structure and table structure of the scene data model are designed, and the scene data modeling and updating strategy is constructed, and the scene modeling case is designed to realize the direct modeling of common geographic data.(3) The requirements of GIS space expression and analysis are analyzed, and a spatial analysis template based on the parameters and operators is constructed. The flow structure and operation characteristics of the common space computation in the geometric algebra framework are studied, and the related geometric algebra expression and operator algorithm are analyzed. Combined with the GIS spatial expression and calculation model, the GIS spatial expression parameter system based on GA and the operator Library of spatial computation is defined. The typical spatial analysis model of the process of segmentation and structural separation are used to inherit, rewrite and construct the operation mode which based on Geometric Algebra for geo spatial computing model. Three kinds of typical spatial templates are constructed, and a demonstration case is given to realize the construction of spatial analysis algorithm based on GA spatial analysis template.(4) The spatial expression structure and operation based on geometric algebra are analyzed. According to the characteristics of geometric algebra, the structure optimization strategy and method of constructing spatial computation geometry algebra expression is constructed according to the requirement of space computation. Based on the geometric algebra vector coding based on bit operation, the algorithm optimization based on the pre multiplication table and the piecewise parallel optimization of multiple vectors, it is designed to optimize the efficiency of the algorithm and the parallel strategy. The common vector and raster algorithm analysis process based on geometric algebra are discussed. By utilizing the independence and unity of the operation flow of geometric algebra, and the particle size segmentation and process decomposition of the configuration and operation of space computing model based on geometric algebra expression are set up, and the parallel computing architecture of the common geometric algebra operators is established, and on the basis of this, the structure of GIS parallel computing algorithm based on geometric algebra is established. The GIS computing engine for parallel optimization is designed, and the development method of the script is introduced, and the dynamic binding of the runtime code by the combination of the geometric algebra layer and the platform layer are realized. The parallel case is designed and the effect of the algorithm is verified.(5) Based on the above theoretical results, a case study is designed for modeling and analysis of multi temporal geographic data. Multi temporal and multi temporal scenario models are established by using the ocean land ice sheet coupling data of 8 million years from the Antarctic. On this basis, an integrated spatial and temporal analysis tool are designed to support the analysis of the geographical phenomenon of this kind of spatial and temporal change. The modeling and visualization of multi dimension data in different dimensions are implemented. The non-intersect sphere tree index is established, which can effectively check the surface and the inner region of any layer at any time. At last, the calculation operator of the basic measurement and morphological characteristics of the scene are designed to obtain the characteristics of the Antarctic space in different phases. Change detection model is used to extract the main features of the structure with the change of time. And the parallel optimization algorithm of scene analysis are discussed.(6) The modeling and analysis of dynamic scenes are designed, and the evacuation routes in the urban scene under the conditions of pollutant constraints are simulated. A template based scenario analysis process is designed, and three basic template structures are used to construct the scene state interpolation, the state update and the relationship calculation template, which can realize the dynamic calculation and update of the path data. At last, the dynamic optimal path finding algorithm with constraints is designed, which can solve the evacuation route in dynamic scene.The research of this paper shows that the GIS scene model based on geometric algebra can meet the requirements of multi dimension, multi factor and dynamic scene analysis. Its design of the data model and template data analysis method to achieve the unity of the scene data organization and scene analysis algorithm for the consistency of the design and solution. It proposed GA based GIS algorithm optimization and parallelization method effectively improve the efficiency of the algorithm. It has a broad prospect in the analysis of large-scale and complex scenes. It designs a case study of multi temporal and multi temporal geographic scene modeling and dynamic constraint modeling, which proposed a new idea for modeling and analyzing and integrating dynamic scene simulation. The integrated modeling and parallel computing method based on geometric algebra is proposed in this paper. This paper hopes to put forward a complete set of modeling and analysis framework for the whole element geo spatial modeling.