The meaning of spatial index

Spatial index refers to a data structure arranged in a certain order based on the position and shape of spatial objects or a certain spatial relationship between spatial objects. It contains summary information of spatial objects, such as object identification and circumscribed rectangles. and pointers to spatial object entities.

Spatial data query, that is, spatial index, is a description of the location information of data stored on the medium. It is used to improve the efficiency of data acquisition by the system, and also Called the spatial access method (Spatial Access Method SAM). It refers to a data structure arranged in a certain order based on the position and shape of spatial objects or a certain spatial relationship between spatial objects. It contains summary information of spatial objects such as the object's identification circumscribed rectangle and pointers to the spatial object entities. (Recommended learning: PHP video tutorial)

Meaning

##As an auxiliary spatial data structure, spatial index is between space Between the operation algorithm and the spatial object, it filters out a large number of spatial objects that are irrelevant to the specific spatial operation, thereby improving the speed and efficiency of the spatial operation.

Common spatial index types include BSP trees, K-D-B trees, R trees, R trees and CELL trees. The superior performance of spatial indexes directly affects spatial databases and geographic information systems. overall performance. Grid spatial indexes with relatively simple structures are widely used in various GIS software and systems (such as ArcGIS).

Fractal theory is a new branch of modern mathematics. Fractal geometry is a geometry that takes irregular geometric forms as its research object. Through in-depth research on fractal theory, some properties of Peano curves have been proved, especially Hilbert space filling, which provides necessary theoretical knowledge for the study of spatial indexes.

Spatial data is one of the core research contents in the field of spatial information. With the rapid development of spatial information infrastructure construction and spatial data acquisition technology, the scale of spatial data is getting larger and larger, and the requirements for spatial data sharing are increasing. At the same time, spatial data warehouse, spatial data mining and other system performance have put forward growing demands. As it becomes increasingly difficult to rely on hardware to improve the performance of database systems, improving spatial data sharing capabilities and enhancing the indexing efficiency of spatial data have become a hot research frontier.

Based on fractal theory, spatial data is effectively and reasonably divided by generating Hilbert curves, and combined with the widely used R-tree space in the current spatial index system, it becomes a new spatial index algorithm and system. It well solves the problems of spatial index speed and index accuracy, and improves the spatial index efficiency of distributed massive spatial data. The details are as follows: an in-depth study of the coding theory of fractal graphics, the method of drawing fractal graphics by L system and iterative function system, a generation scheme for Hilbert space filling curves, and a scanning matrix algorithm were designed.

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