The Study Of Sphere Rhombus Grid Recursive Subdivision

In the view of information technology and space technology continue todevelopment，progress and improve,especially in the the fast development of globalpositioning technology and global remote sensing,the scope of the remote sensingdynamic monitoring extended to a global scale. People can acquire multi-resolution,real-time, massive, dynamic observation data of the earth.With these informationpeople can research sustainable development for the human world, resourceenvironment monitoring, national security, disaster early warning and forecast and so on.In this context, the traditional data model plane have been unable to fully meet theglobal spatial information management. It is one of the effective methods to build aglobal, hierarchy,continuity,and dynamic levels of spherical data model to solve theproblem.The new model will fundamentally solve the limitations of traditional model.Inthis paper,the studies are around the spherical discrete global grids model, complete themain work is as follows:1. On the basis of summing up the existing subdivision models,in view of theiradvantages and disadvantages,and weighing the five evaluation,proposed a new globalsubdivision model--recursive subdivision model based on the geographical coordinatesof the Sphere Rhombus Grid.This method of plotting split uses similar rhombus assubdivision units. Rhombus structure is similar to a square grid,with consistentdirectional characteristics,and so on.It does not depend on the mapping method from thepolyhedron surface to the surface of a sphere or ellipsoid and can directly use thealgorithm based on flat quadtree.so operation in space is easier to achieve,especiallyneighboring search.The subdivision process is a combination of latitude andlongitude,so conversion between the split coded with latitude and longitude coordinatesis relatively simple.Combines not only longitude and latitude and but also the thinkingof regular polyhedron’s recursive subdivision. It subdivides the earth directly on thesphere, with no internal polyhedron,no projection and simple operation. The method canachieve a seamless sphere without overlapping, with any resolution adopted subdivision.Proposed the split coding scheme, based on the SRG split model.Proposed linear ranksnumber and Grid ranks number,so as the correspondence and mutual conversionalgorithm between them,and other related content.2. Basing on Sphere Rhombus Grid, a translating algorithm between SRGsubdivision codes and latitude/longitude coordinates is proposed. The algorithm inheritsthe advantages of SRG Subdivision,SRG Subdivision code has a fixed direction, SRGsubdivision does not involve any projection transformation,so does translatingprocess.When calculating, only use addition, subtraction, multiplication and divisionsimple arithmetic, so calculation is faster.And use coordinate system to assist the distinction between rhombus-shaped pieces which are difficult to distinguish.and alsoruduce error rate of the translation, improve accuracy of the translation.3. Based on sphere Rhombus Grid model, proposed a neighboring search algorithm.The algorithm is an application of the SRG split model. overcomes the QTM gridinsufficient. SRG model uses imilar rhombus as subdivision units. The rhombusstructure has many advantages,high similarity,facilitate the clustering and statisticalanalysis,hierarchy, with a radially symmetric and the direction of consistency.Easy toneighboring search and query operation.The algorithm only simple arithmeticoperations,and when searching,9/16of the grid can directly find from the formaccording to the to the outcome,the search more efficient.4.The translating algorithm presented in this paper between SRG subdivision codesand latitude/longitude coordinates is compared with the existing algorithms.Theexperiments and the comparion show the merits. Although the conversion rate of thealgorithm in this paper is a bit slow than" ranks the approximation",but it can ruduceerror rate, improve accuracy of the translation. The neighboring search algorithm thispaper presented, only simple arithmetic operations,and when searching,9/16of the gridcan directly find from the form according to the to the outcome,the search moreefficient.