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HPSIN: a new hybrid P2P spatial indexing network

The Journal of China Universities of Posts and Telecommunications 2010年第3期17卷 66-72页

作者： WU Jia-gao JIANG Nan ZOU Zhi-qiang HU Bin HUANG Lin FENG Jia-li Institute of Computer Technology Nanjing University of Posts & Telecommunications Nanjing 210003 China Key Laboratory of Virtual Geographic Environment Ministry of Education Nanjing Normal University Nanjing 210046 China School of Geographic and Oceanographic Sciences Nanjing University Nanjing 210093 China

Geographic information system （GIS） is increasingly managing very large sets of data, hence a centralized data index may not always provide the most scalable solution. Recently, the peer to peer （P2P） networks have become very popular for sharing information in a totally decentralized manner. In this paper, a new hybrid P2P spatial indexing network （HPSIN） is proposed, which combines distributed quad-tree with distributed Hash table （DHT） based Chord network to maintain both query efficiency and system load balance. In addition, a simple theoretical model based on opened queueing network for HPSIN is established. Assuming each peer as M/M/1 queueing processor in the model, fundamental characteristics of the system is captured, and expression of average query delay is obtained in close form. The theoretical analysis and numerical computing results show that there exists an optimum point of tradeoff between efficiency and load balance. By setting a proper value of start index level ls for different network scale and query rate, HPSIN will achieve the minimum overall query delay, therefore, can adapt to different P2P application environments.

关键词： GIS P2P networks spatial indexing queueing network theory

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Area and shape distortions in open-source discrete global grid systems

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Big Earth Data 2022年第3期6卷 256-275页

作者： Alexander Kmoch Ivan Vasilyev Holger Virro Evelyn Uuemaa Department of Geography Institute of Ecology and Earth SciencesUniversity of TartuTartuEstonia

A Discrete Global Grid System(DGGS)is a type of spatial reference system that tessellates the globe into many individual,evenly spaced,and well-aligned cells to encode location and,thus,can serve as a basis for data cube *** facilitates integration and aggregation of multi-resolution data from various sources to rapidly calculate spatial *** calculated normalized area and compactness for cell geometries from 5 open-source DGGS implementations-Uber H3,Google S2,RiskAware OpenEAGGR,rHEALPix by Landcare Research New Zealand,and DGGRID by Southern Oregon University-to evaluate their suitability for a global-level statistical data *** conclude that the rHEALPix and OpenEAGGR and DGGRID ISEA-based DGGS definitions are most suitable for global statistics because they have the strongest guarantee of equal area preservation-where each cell covers almost exactly the same area on the *** H3 has the smallest shape distortions,but Uber H3 and Google S2 have the largest variations in cell ***,they provide more mature software library *** provides excellent functionality to construct grids with desired geometric properties but as the only implementation does not provide functions for traversal and navigation within a grid after its construction.

关键词： Coordinate reference systems spatial indexing big spatial data analytics data cube DGGS

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Kd-tree and quad-tree decompositions for declustering of 2D range queries over uncertain space

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Frontiers of Information Technology & Electronic Engineering 2015年第2期16卷 98-108页

作者： Ahmet SAYAR Suleyman EKEN Okan OZTURK Department of Computer Engineering Kocaeli University Kocaeli 41380 Turkey

We present a study to show the possibility of using two well-known space partitioning and indexing techniques, kd trees and quad trees, in declustering applications to increase input/output （I/O） paraUelization and reduce spatial data processing times. This parallelization enables time-consuming computational geometry algorithms to be applied efficiently to big spatial data rendering and querying. The key challenge is how to balance the spatial processing load across a large number of worker nodes, given significant performance heterogeneity in nodes and processing skews in the workload.

关键词： Kd tree Quad tree Space partitioning spatial indexing Range queries Query optimization

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