A trie-based range query method and device

A query method and scope technology, which can be applied to other database queries, instruments, geographic information databases, etc., can solve problems such as large space overhead, and achieve the effect of reducing space overhead and improving query efficiency.

Active Publication Date: 2021-06-18
KUNMING UNIV OF SCI & TECH
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  • Summary
  • 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 methods usually build a Trie index structure based on complete strings, so the space overhead is large

Method used

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  • A trie-based range query method and device
  • A trie-based range query method and device
  • A trie-based range query method and device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Embodiment 1: as Figure 1-7 As 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, and the longitude and latitude bit strings are 20 bits respectively;

[0044] Step 112, convert the position point in D into a character string with a length of 8 through the geohash algorithm, and the implementation method is as follows:

[0045] Example: (19.596412 -99.219501)

[0046] First divide the latitude range (-90,90) 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 encoded 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 Coded as 0; and so on until the length of the bit string is 20. The final encoding...

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 Trie-based range query method and device. The method of the invention includes: a data preprocessing step, encoding all position points in a data set into a character string with a length of n, and lexicographically ordering the data in the data set according to the string suffix The location points are sorted and numbered ID; the spatial index building step is to construct a Trie spatial index structure according to the sorted string prefix; the range query step is to obtain the location points in the query domain on the index structure, obtain the candidate set after filtering, and compare the candidate set Validate returns all location points within the query range. The present invention adopts a partial Trie index structure constructed based on string prefixes, and has high query efficiency while reducing space overhead; and adopts a geohash spatial index method to effectively support any range query.

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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Patent Type & Authority Patents(China)
IPC IPC(8): G06F16/29G06F16/9537G06F16/903
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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