Raster data rapid vectorization method combining run-length coding and edge tracking

Abstract

A raster data rapid vectorization method combining run-length coding and edge tracking comprises two steps of run-length coding and edge tracking, and edge tracking comprises the steps of determininga tracking entrance and an initial direction, determining a tracking rule, marking a run length, and judging and processing an inner ring and an outer ring. The step of determining the tracking rule comprises generating a 4-connected region and an 8-connected region. The run length marking step comprises marking related run length codes in the tracking process, the inner and outer ring judgment and processing step comprises judgment of an inner ring and an outer ring and association of the inner ring and the outer ring, and the whole algorithm process is divided into six steps. According to the method, the occupied memory space is greatly reduced, 4-connected polygons and 8-connected polygons can be generated, the search efficiency is improved, the middle process of generating arc sectionsby node points is omitted, and the closed boundary generation efficiency is improved. For the polygon with the inner ring, the inner boundary quickly corresponds to the outer boundary, so that the generation efficiency of the polygon with the inner ring is improved, and the vectorization efficiency is further improved.

Description

technical field [0001] The invention relates to the field of vectorization method of large-scale remote sensing classification grid data in remote sensing science and technology and geographic information system, in particular to a fast vectorization method of grid data combining run-length coding and edge tracking. Background technique [0002] In the processing of surveying and mapping information in geography, natural resources, ecological environment, agriculture and other departments, the conversion between raster data and vector data is often involved. Raster data and vector data are two important data storage formats. Raster data has the characteristics of large storage capacity and a large amount of data redundancy; vector data only stores node information and has the characteristics of occupying a small storage space, so usually Store data in a vector format. Remote sensing classification data is essentially a form of raster data, which takes up a lot of storage sp...

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Problems solved by technology

[0005] In order to overcome the disadvantages of low efficiency of the existing raster vectorization technology, the present invention solves the problem of large memory space occupied by traditional methods through run-length coding, and realizes fast mapping of the inner ring and outer ring by setting certain tracking marks, and the vector In the process of transformation, the outer ring is first generated, the index value of the outer ring is recorded, and the related run-length code is numbered; when the inner ring is generated, the index corresponding to the outer ring can be quickly found through the number value corresponding to the run-length code. Directly bind the inner ring and the corresponding outer ring together, eliminating the need to include the process of judging the topological relationship, thereby improving the efficiency of vectorization, a fast vectorization method for raster data that combines run-length coding and edge tracking

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