Range query method and device based on Trie

A query method and range of technology, applied in special data processing applications, instruments, electrical digital data processing, etc., can solve problems such as large space overhead, and achieve the effect of reducing space overhead and high query efficiency

Active Publication Date: 2018-03-13
KUNMING UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The method of using Trie to store geohash codes, such as: STCode, GeoTrie, MP-Trie, etc., but the above

Method used

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  • Range query method and device based on Trie
  • Range query method and device based on Trie
  • Range query method and device based on Trie

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Example 1: as Figure 1-7 shown, a Trie-based range query method, including

[0042] Data preprocessing steps:

[0043] Step 111. According to the geohash precision table (such as figure 2 shown), set the geohash encoding length n to 8, then the longitude and latitude bit strings are 20 bits respectively;

[0044] Step 112: Convert the position point in D into a string of length 8 through the geohash algorithm. The implementation method is as follows:

[0045] Example: (19.596412 -99.219501)

[0046] First, the latitude range (-90,90) is divided into two intervals (-90,0) and (0,90). If the target latitude is in the previous interval, it is coded as 0, otherwise it is coded as 1. Because 19.596412 belongs to the interval (0,90), it is coded as 1; then (0,90) is divided into two intervals (0,45) and (45,90), because 19.596412 belongs to the interval (0,45), so The encoding is 0; and so on, until the bit string length is 20. The final encoding of 19.596412 is 10011...

Embodiment 2

[0093] Embodiment 2: as Figure 1-7 As shown, a Trie-based range query method includes:

[0094] The data preprocessing step is to encode all the position points in the data set into a string of length n, sort the position points in the data set according to the lexicographical order according to the string suffix and number the ID;

[0095] The spatial index building step is to construct a Trie spatial index structure according to the sorted string prefix;

[0096] In the range query step, the location points in the query domain are obtained from the index structure, the candidate set is obtained by filtering, and all the location points in the query range are returned after the candidate set is verified.

[0097] Further, the data preprocessing step may be set, specifically including the following steps:

[0098] Step 110: Given a data set D consisting of a series of location points, the location points in D are encoded into a string s of length n by geohash algorithm; whe...

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Abstract

The invention relates to a range query method and device based on Trie. The method comprises the following steps that: data preprocessing: coding all position points in a dataset into a character string of which the length is n, and sorting the position points in the dataset according to a character string suffix and a lexicographical order, and numbering ID (Identity); spatial index establishment: according to a sorted character string prefix, constructing a Trie spatial index structure; and range query: on the index structure, obtaining the position points in a query domain, filtering to obtain a candidate set, and verifying and returning all position points in the query range to the candidate set. By use of the method, on the basis of the character string prefix, parts of Trie index structure are constructed, query efficiency is high while space overhead is lowered, a geohas spatial index method is adopted to effectively support the query of any range.

Description

technical field [0001] The invention relates to a Trie-based range query method and device, and belongs to the fields of spatial database (SpatialDatabase), spatial keyword query, geographic information system (Geographic Information System, GIS) and other fields. Background technique [0002] With the popularization of mobile devices, the rapid development of positioning technology, and the rapid development of location-based services (Location-Based Service, LBS), etc., the amount of spatial data is increasing rapidly. [0003] Massive spatial data requires efficient spatial indexing technology. Spatial index is used to filter and exclude a large number of geographical objects irrelevant to specific spatial operations, thereby reducing the scope of spatial operations. The performance of spatial indexes directly affects the availability and scalability of spatial databases. From the point of view of spatial database, the spatial index structure can be divided into two cate...

Claims

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Application Information

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IPC IPC(8): G06F17/30
CPCG06F16/29G06F16/90344G06F16/9537
Inventor 沈兵林贾连印丁家满游进国李晓武陈文焰章露露吕晓伟
Owner KUNMING UNIV OF SCI & TECH
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