Space Object Aggregation Based On Mixed Spherical Degenerated Grid

With the development of earth observation technology, the range of spatial data’sapplication and management is gradually extended from local to global. A model of theoperation and management of the Global Spatial Data is badly in need. This paper makes a studyof utilizing hybrid spherical degradation model based on the regular octahedron compatible withthe existing grid subdivision model and the aggregation of spatial objects to carry out research.The main work and innovations of this paper are summarized as follows:1. This paper makes a detailed description of the study and application of global geographicgrid subdivision and an analysis of the significance in the work of aggregating vector objectsand grid object of different types or different split method. Some key technologies such as thecoding pattern of the grid, the aggregation of different grid objects, and the grid aggregation ofvector objects were also discussed.2. According to the degraded thinking (from QTM to DQG), with further degradation,Mixed Spherical Degenerated Grid (MSDG) is brought forward and realized the expression inthe latitude and longitude coordinates. And an evaluation of the important indicator of thedivided grid is made. Facilitating the conversion between code and coordinates (range), thepresented fixed-length binary encoding method is fit for the coordinate computation and objectaggregation. Through analysis of the subdivision methods and coding rules, the conversionformulas between MSDG grid coding and the latitude and longitude coordinates (range) areestablished.3. After an analysis of the division method, coding rules of geographic grid and the nationalstandard map, mutual aggregation and expression means of different grid object are put forward,with the aggregation accuracy verified. The characteristics of the MSDG grid subdivision getfurther analysis.4. On the basis of triangulation MSDG subdivision, principle and model of MSDG gridaggregation as well as the aggregation method of focus and polygon are presented. Realized theaggregation of the linear object making use of the intersection of the linear object and the line ofMSDG subdivision, realized the aggregation of the area object through judgment method for therelation of the point with polygon, and realized the multi-scale aggregation of the area objectbasis of the principle of decreasing the number of aggregation unit and keeping the precision ofaggregation.Based on the coherence of topology relationship, a new multi-scale aggregationmethod of space object is proposed and implemented.