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Compression method of gps track data based on lzw algorithm

A technology of trajectory data and compression method, applied in geographic information database, structured data retrieval, code conversion, etc., can solve the problem that the file type has no specific requirements.

Active Publication Date: 2022-04-15
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the LZW compression algorithm is often used to compress text files, it does not have specific requirements for file types

Method used

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  • Compression method of gps track data based on lzw algorithm
  • Compression method of gps track data based on lzw algorithm
  • Compression method of gps track data based on lzw algorithm

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Experimental program
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Effect test

Embodiment 1

[0084] 1. Obtain GPS track data

[0085] The original trajectory data (see Table 1 and Table 2) includes the time stamp (time), the latitude and longitude (longitude and latitude) of the position coordinates, and the ID (tid) of the trajectory.

[0086] Table 1 Raw trajectory data format

[0087]

[0088] Table 2 Example of raw trajectory data

[0089]

[0090] 2. Map matching

[0091] The matching road network trajectory is the trajectory data after the original trajectory data is matched to the road network after map matching. We used the method in the paper [11] to map the GPS data to the map to obtain the matching road network trajectory data. The meanings of the fields contained in the matched data (Table 4) are shown in Table 3.

[0092]Table 3 Matching road network trajectory data format

[0093]

[0094]

[0095] Table 4 Example of matching road network trajectory data

[0096]

[0097] 3. Trajectory data decompression

[0098] 3.1 Trajectory data...

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Abstract

The invention relates to a compression algorithm, specifically a method for compressing GPS trajectory data based on the LZW algorithm. This method combines traditional trajectory data with road network information, and converts the original trajectory data into road segment sequence representations by means of map matching. Afterwards, in order to facilitate processing, a coding rule is customized to convert the road segment trajectory data into text-type data, and finally the transformed text-type trajectory data is compressed and decompressed using the LZW compression algorithm. The present invention converts the track data into the form of text data by using processing methods such as map matching, mapping track, and road section number conversion, so that it can be compressed by using the LZW algorithm. Compared with other algorithms, this method ensures the compression ratio while ensuring the operation efficiency.

Description

technical field [0001] The invention relates to a compression algorithm. Background technique [0002] Based on the development of location-acquisition technology, we can obtain a large amount of trajectory information, representing the movement information of pedestrians, vehicles, wild animals, hurricanes and so on. Trajectory data is a kind of spatiotemporal data [1]. A trajectory records the position information of a moving object under a series of sampling times. For example, the movement trajectory of an object is: p 1 >p 2 >…>p n , each point contains the geographic location coordinates and time stamp information of the moving object, such as p=(x,y,t). Trajectory information can help us better understand the behavior characteristics of moving objects, and promote the development of location-based applications, intelligent transmission networks, and smart cities. The popularity of these applications has in turn stimulated the research on trajectory data ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03M7/30G06F16/29
CPCH03M7/3088
Inventor 赵钦佩饶卫雄史扬李江峰
Owner TONGJI UNIV