Rapid building method of tile pyramid for large-scale raster data set

Abstract

The invention belongs to the field of treatment of geographic information, and relates to a rapid building method of a tile pyramid for a large-scale raster data set. The method comprises the steps that 1, the data set comprising image files is obtained; 2, the image files in the data set are traversed, and a spatial index file is built; 3, the tile pyramid maximum hierarchy and the image file number threshold value are set; the iteration variable k initial value is defined as the tile pyramid maximum hierarchy; 4, the current hierarchy single-tile range retrieved image file number is compared with the threshold value; if the image file number is smaller than or equal to the set threshold value, each tile in the hierarchy is traversed, an xml type character string of each tile is generated to be transferred to a Mapnik drawing engine for drawing and stored into the corresponding hierarchy of the pyramid; if the image file number is larger than the set threshold value, tile data of the existing k+1 hierarchies is called, and resampling is carried out to generate tile data of k hierarchies to be stored into the corresponding hierarchies; 5, 1 is subtracted from the current hierarchy number k, if the result is larger than 0, the step 4 is executed again, and if not, the process is finished.

Description

technical field [0001] The invention belongs to the technical field of geographic information processing, and relates to a method for quickly constructing a tile pyramid of a large-scale raster image data set in a geographic information system. Background technique [0002] With the development of geospatial data acquisition technology, many functional institutions and research groups at home and abroad have been able to obtain higher-resolution image maps more conveniently. In particular, the rapid advancement of UAV aerial photography technology has made it possible to obtain high-resolution image data sets in counties and regions. High-resolution image data is generally stored in a disk file system as a large number of raster data in the same format that is continuous in geographical distribution and discrete in file storage, but the large-scale nature of the data limits its efficient organization and indexing in traditional relational databases Access becomes the effici...

AI Technical Summary

Problems solved by technology

[0006] Judging from the research status, the existing GIS system needs preprocessing processes such as image stitching and pyramid construction to generate a complete tile pyramid to provide map tile services, which increases the overall time for data set visualization

Moreover, in the process of data processing, the idea of ​​parallelization is seldom used, and hardware computing resources cannot be effectively used.

When processing large-scale raster datasets according to this set of traditional processes, it takes a long time for data preprocessing, especially the efficiency of splitting tile pyramids is extremely low, and there are few optimization studies on the construction of tile pyramids

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