Table of Content

31 December 2016, Volume 45 Issue S1

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Overview of the Research Progress in the Earth Tessellation Grid

ZHAO Xuesheng, BEN Jin, SUN Wenbin, TONG Xiaochong

2016, 45(S1):  1-14.  doi:10.11947/j.AGCS.2016.F001

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By analyzing the related literatures on the earth tessellation grid (ETG) in recent 10 years, the research achievements in this field are systematic reviewed in four aspects, i.e. the earth subdivision modeling (include quadrangle subdivision, equal-area subdivision and 3D subdivision), encoding computation (include hierarchical encoding computation, filling curve encoding computation and integer coordinate encoding computation), grid quality assessment (include evaluation criteria, evaluation factors, and propagation trend in diffferent levels) and typical applications (include government agency applications,business software applications and industry applications). The structural characteristics, applicable models and their shortcomings in the different grid models are given in details. Finally, some advanced academic problems in the ETG are given based on the completeness of basic theory, the efficiency of grid computing, and the reliability of grid quality.

The Historical Evolution and Reflection of Geospatial Information Grid

WAN Gang, CAO Xuefeng

2016, 45(S1):  15-22.  doi:10.11947/j.AGCS.2016.F002

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With the development of science and practices, the grid concept continues to evolve, and there are differences and relations between different industries about understanding of its connotation. First, the theoretic characteristics of Geospatial Grid are analyzed and its broad and narrow concept is put forward. Then the history of Geospatial Grid development is reviewed and analyzed, and Geospatial Grid is considered as one kind human spatial cognition theory, and it developed into Geospatial Information Grid under the condition of information. At the end, this paper argues that the research object of Geospatial Information Grid is the informational earth system and it is based on the model theory, the service and standards system will be constructed, and the service range extends from human to intelligent platforms at that time which leading to a bright future.

Coding Model and Mapping Method of Spherical Diamond Discrete Grids Based on Icosahedron

LIN Bingxian, XU Depeng, SHENG Yehua, LÜ Guonian, ZHOU Liangchen

2016, 45(S1):  23-31.  doi:10.11947/j.AGCS.2016.F003

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Discrete Global Grid(DGG) provides a fundamental environment for global-scale spatial data's organization and management. DGG's encoding scheme, which blocks coordinate transformation between different coordination reference frames and reduces the complexity of spatial analysis, contributes a lot to the multi-scale expression and unified modeling of spatial data. Compared with other kinds of DGGs, Diamond Discrete Global Grid(DDGG) based on icosahedron is beneficial to the spherical spatial data's integration and expression for much better geometric properties. However, its structure seems more complicated than DDGG on octahedron due to its initial diamond's edges cannot fit meridian and parallel. New challenges are posed when it comes to the construction of hierarchical encoding system and mapping relationship with geographic coordinates. On this issue, this paper presents a DDGG's coding system based on the Hilbert curve and designs conversion methods between codes and geographical coordinates. The study results indicate that this encoding system based on the Hilbert curve can express space scale and location information implicitly with the similarity between DDG and planar grid put into practice, and balances efficiency and accuracy of conversion between codes and geographical coordinates in order to support global massive spatial data's modeling, integrated management and all kinds of spatial analysis.

Degenerate Quadtree Latitude/Longitude Grid Based on WGS-84 Ellipsoidal Facet

HU Bailin, WANG Chunbo, ZHAO Xuesheng, CUI Majun

2016, 45(S1):  32-39.  doi:10.11947/j.AGCS.2016.F004

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For the needs of digital earth development and solving many global problems, a new discrete global grid system-DQLLG (degenerate quadtree latitude/longitude grid) was put forward, which was based on WGS-84 ellipsoidal facet. The hierarchical subdivision method, characteristics and grid column/row coordinate system were detailed. The Latitude/Longitude coordinate, area and side length of multi-resolution meshes on different subdivision levels were calculated. Then the changes of mesh areas and side lengths were analyzed and compared that with spherical DQLLG. The research indicates that the DQLLG had many excellent features:uniformity, hierarchy, consistency of direction, extensive data compatibility and so on. It has certain practicality for Global GIS in the future.

The Framework of Earth System Cellular Automata Based on SDOG-ESSG and Its Preliminary Experiment

YU Jieqing, SHI Zhen, WU Lixin, XING Songwei, JIA Yongji

2016, 45(S1):  40-47.  doi:10.11947/j.AGCS.2016.F005

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Cellular Automata (CA) has been widely adopted in atmosphere, hydrodynamics, geophysics and geoscience for its simple structure and capability of simulating complex system. Existing CAs in geoscience ignore the restraints of gravity, and do earth system processes simulation under the constraints of Euclidean, which is not in accord with the tendency of state delivery from one cell to cell, and will produce some distortions on the results. This paper is to propose an Earth System Cellular Automata (ESCA) based on the restraint of gravity. The framework, including cell representation and construction, and neighbor model based on SDOG-ESSG, was proposed in the paper. As evolution rules are highly depended on actual problems, the problem of heat conduction in the Crust was taken as an example to design an evolution rule for the ESCA by imposing a discretization on thermodynamics law. Finally, a preliminary experiment and a comparison with numerical simulation in local scale were carried out. Results showed that, ESCA is reliable to some extent with its relative error limited to 27% comparing with numerical simulation. ESCA can be a new way of simulation for earth system process.

Analysis and Research on Several Global Subdivision Grids

SONG Shuhua, DONG Fang, WAN Yuanwei, ZHAO Jinling, LI Shizhong, XI Fubiao, CHEN Kai, ZHANG Le, CHEN Dong

2016, 45(S1):  48-55.  doi:10.11947/j.AGCS.2016.F006

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In order to solve the problem that lacking of an unified organization frame about global remote sensing satellite image data, this paper introduces serval global subdivision grids as the unified organization frame for remote sensing image. Based on the characteristics of remote sensing image data, this paper analyzes and summarizes the design principles and difficulties of the organization frame. Based on analysis and comparison with these grids, GeoSOT is more suitable as the unified organization frame for remote sensing image. To provide a reference for the global remote sensing image organization.

Some Metric Problems on the Global Grid Systems

HU Hai, YOU Lian, SONG Lili, HU Peng

2016, 45(S1):  56-65.  doi:10.11947/j.AGCS.2016.F007

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The Discrete Global Grid Systems (or the global position location framework) is a kind of scientific and concise spatial reference system, which is the discretization, accurate and systematic representation of the earth information data. In recent years, with the development of GPS and Beidou satellite system and the process of globalization, the global metric and accuracy of spatial analysis should be pay more attention by people. In this paper, first, for the progress and insufficiency over recent years of the earth grid research, the author discusses several quantity issues include:the integrity of meshing, logical consistency, and some related problems. Then regarding the questions of position and metric, the author points out that the Earth is the target object of meshing its characteristics of metric space. The revolutionary demand of "3D structure and centimeter level accuracy" will have a significant impact on global GIS system. Next, the 3D meshing approaches to the ellipsoid of the earth are stressed, and the author also introduces the corresponding experiments and theoretical approach in map algebra on the 3D earth meshing. Finally, this paper reaffirms that the 3 sets of (B, L, H) orthogonal surface should be the most appropriate way on metric for the Earth meshing.

An Efficient Integer Coding and Computing Method for Multiscale Time Segment

TONG Xiaochong, WANG Rong, WANG Lin, LAI Guangling, DING Lu

2016, 45(S1):  66-76.  doi:10.11947/j.AGCS.2016.F008

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This article focus on the exist problem and status of current time segment coding, proposed a new set of approach about time segment coding: multi-scale time segment integer coding (MTSIC). This approach utilized the tree structure and the sort by size formed among integer, it reflected the relationship among the multi-scale time segments: order, include/contained, intersection, etc., and finally achieved an unity integer coding processing for multi-scale time. On this foundation, this research also studied the computing method for calculating the time relationships of MTSIC, to support an efficient calculation and query based on the time segment, and preliminary discussed the application method and prospect of MTSIC. The test indicated that, the implement of MTSIC is convenient and reliable, and the transformation between it and the traditional method is convenient, it has the very high efficiency in query and calculating.

Hilbert Curve Hierarchical Evolution Relationship

CAO Xuefeng, WAN Gang, ZHANG Zongpei

2016, 45(S1):  77-84.  doi:10.11947/j.AGCS.2016.F009

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Grid code algebra is the difficult of current global spatial grid research, and it is the theoretic basis for the development from data organization framework to the new generation of spatial analysis model. Hilbert curve has been an important tool in the global spatial grid code design. In this paper, the octree grid code is based on Hilbert curve, then Hilbert curve hierarchical evolution relationship table is presented, which is used to design some grid code algebra operator. This work provides a reference for the construction of global spatial grid analysis theory and methods.

Geo-spatial Cognition on Human's Social Activity Space Based on Multi-scale Grids

ZHAI Weixin, DUAN Jiexiong, TONG Xiaochong, CHENG Chengqi, SONG Shuhua, LI Shuang

2016, 45(S1):  85-89.  doi:10.11947/j.AGCS.2016.F011

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Widely applied location aware devices, including mobile phones and GPS receivers, have provided great convenience for collecting large volume individuals' geographical information. The researches on the human's society behavior space has attracts an increasingly number of researchers. In our research, based on location-based Flickr data From 2004 to May, 2014 in China, we choose five levels of spatial grids to form the multi-scale frame for investigate the correlation between the scale and the geo-spatial cognition on human's social activity space. The HT-index is selected as the fractal inspired by Alexander to estimate the maturity of the society activity on different scales. The results indicate that that the scale characteristics are related to the spatial cognition to a certain extent. It is favorable to use the spatial grid as a tool to control scales for geo-spatial cognition on human's social activity space.

Compact Hilbert Curve Index Algorithm Based on Gray Code

CAO Xuefeng, WAN Gang, ZHANG Zongpei

2016, 45(S1):  90-98.  doi:10.11947/j.AGCS.2016.F010

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Hilbert curve has best clustering in various kinds of space filling curves, and has been used as an important tools in discrete global grid spatial index design field. But there are lots of redundancies in the standard Hilbert curve index when the data set has large differences between dimensions. In this paper, the construction features of Hilbert curve is analyzed based on Gray code, and then the compact Hilbert curve index algorithm is put forward, in which the redundancy problem has been avoided while Hilbert curve clustering preserved. Finally, experiment results shows that the compact Hilbert curve index outperforms the standard Hilbert index, their 1 computational complexity is nearly equivalent, but the real data set test shows the coding time and storage space decrease 40%, the speedup ratio of sorting speed is nearly 4.3.

Research on Real Estate Unit Unified Identifier Model Based on GeoSOT Code

SONG Shuhua, DONG Fang, CHEN Dong, ZHAO Jinling, LI Bin, ZHANG Le, WANG Xiying, LI Shizhong, ZHAI Weixing, SUN Zhongqiu

2016, 45(S1):  99-105.  doi:10.11947/j.AGCS.2016.F012

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It is a spatial uncertainty for existing real estate unit identifier. So, in order to reflect the spatial position based on real estate unit identifier directly, it proposes a real estate unit code model based on GeoSOT code, encoding method, and the spatial location information transformation scheme between this model and spatial location, after we study the existing real estate unit identifier model. The test shows that it is very useful and direct to show the spatial location with the real estate unit identifier based on GeoSOT code.

A Study on Data Storage and Management for Massive Remote Sensing Data Based on Multi-level Grid Model

LI Shuang, CHENG Chengqi, TONG Xiaochong, CHEN Bo, ZHAI Weixin

2016, 45(S1):  106-114.  doi:10.11947/j.AGCS.2016.F013

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With the rapid development of remote sensing technology, spatial information is exploding. For current remote sensing data storage management system, their data volume, rich data sources, query retrieves slow and other issues are problems to be solved. This paper then proposed a remote sensing data organization scheme based on GeoSOT. By firstly adding a GeoSOT code column which is array format in relational database, spatial information in the metadata can be stored and logically subdivided, in order to achieve unified storage and retrieval of image data space area. We compare our method with Oracle platform by simulating worldwide image data. Experimental results show that the retrieval efficiency of this article has obvious advantages and can effectively improve the integration of remote sensing data, retrieval efficiency. Our approach also offers a more effective storage management program for existing storage center or management system.

Geospatial Information Service System Based on GeoSOT Grid & Encoding

LI Shizhong, CHENG Chengqi, WANG Dong, PU Guoliang, CHEN Bo

2016, 45(S1):  115-120.  doi:10.11947/j.AGCS.2016.F014

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With the rapid development of the space and earth observation technology, it is important to establish a multi-source, multi-scale and unified cross-platform reference for global data. In practice, the production and maintenance of geospatial data are scattered in different units, and the standard of the data grid varies between departments and systems. All these bring out the disunity of standards among different historical periods or orgnizations. Aiming at geospatial information security library for the national high resolution earth observation, there are some demands for global display, associated retrieval and template applications and other integrated services for geospatial data. Based on GeoSOT grid and encoding theory system, "geospatial information security library information of globally unified grid encoding management" data subdivision organization solutions have been proposed; system-level analyses, researches and designs have been carried out. The experimental results show that the data organization and management method based on GeoSOT can significantly improve the overall efficiency of the geospatial information security service system.

Police Spatial Big Data Location Code and Its Application Prospect

HU Xiaoguang, GAO Shuhui, TONG Xiaochong, CHENG Chengqi, CAI Nengbin

2016, 45(S1):  121-126.  doi:10.11947/j.AGCS.2016.F015

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The rich decision-making basis are provided for police work by police spatial big data. But some challenges are also brought by it, such as:large data integration complex, multi scale information related difficulties, the location identification is not unique. Thus, how to make the data better service to the police work reform and development is a problem need to be study. In this paper, we propose location identification method to solve the existing problems. Based on subdivision grid, we design the location encoding method of police spatial big data, and choose domicile location identification as a case. Finally, the prospect of its application is presented. So, a new idea is proposed to solve the problem existing in the police spatial data organization and application.

A Method of Vector Map Multi-scale Representation Considering User Interest on Subdivision Gird

YU Tong, DENG Shujun, QIAN Haizhong, YANG Qingli

2016, 45(S1):  127-134.  doi:10.11947/j.AGCS.2016.F016

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Compared with the traditional spatial data model and method, global subdivision grid show a great advantage in the organization and expression of massive spatial data. In view of this, a method of vector map multi-scale representation considering user interest on subdivision gird is proposed. First, the spatial interest field is built using a large number POI data to describe the spatial distribution of the user interest in geographic information. Second, spatial factor is classified and graded, and its representation scale range can be determined. Finally, different levels of subdivision surfaces are divided based on GeoSOT subdivision theory, and the corresponding relation of subdivision level and scale is established. According to the user interest of subdivision surfaces, the spatial feature can be expressed in different degree of detail. It can realize multi-scale representation of spatial data based on user interest. The experimental results show that this method can not only satisfy general-to-detail and important-to-secondary space cognitive demands of users, but also achieve better multi-scale representation effect.

An Optimization Method for Virtual Globe Ocean Surface Dynamic Visualization

HUANG Wumeng, CHEN Jing

2016, 45(S1):  135-143.  doi:10.11947/j.AGCS.2016.F017

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The existing visualization method in the virtual globe mainly uses the projection grid to organize the ocean grid. This special grid organization has the defects in reflecting the difference characteristics of different ocean areas. The method of global ocean visualization based on global discrete grid can make up the defect of the projection grid method by matching with the discrete space of the virtual globe, so it is more suitable for the virtual ocean surface simulation application.But the available global discrete grids method has many problems which limiting its application such as the low efficiency of rendering and loading, the need of repairing grid crevices. To this point, we propose an optimization for the global discrete grids method. At first, a GPU-oriented multi-scale grid model of ocean surface which develops on the foundation of global discrete grids was designed to organize and manage the ocean surface grids. Then, in order to achieve the wind-drive wave dynamic rendering, this paper proposes a dynamic wave rendering method based on the multi-scale ocean surface grid model to support real-time wind field updating. At the same time, considering the effect of repairing grid crevices on the system efficiency, this paper presents an efficient method for repairing ocean surface grid crevices based on the characteristics of ocean grid and GPU technology. At last, the feasibility and validity of the method are verified by the comparison experiment. The experimental results show that the proposed method is efficient, stable and fast, and can compensate for the lack of function of the existing methods, so the application range is more extensive.

Research on the Method of Urban Waterlogging Flood Routing Based on Hexagonal Grid

LAI Guangling, TONG Xiaochong, ZHANG Yong, DING Lu, LI Kai, FAN Shuaibo

2016, 45(S1):  144-151.  doi:10.11947/j.AGCS.2016.F018

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An evolution of the urban waterlogging flood routing was studied in this paper based on the method of hexagonal grid modeling. Using the method of discrete grid, established an urban geometry model on account of the regular multi-scale discrete grid. With the fusion of 3D topographic survey data and 2D building vector data, formed a regular network model of surface. This model took multi special block into account, such as urban terrain and buildings. On this basis, a method of reverse flow deduction was proposed, which was an inverse computation from the state of flood to the evolution process. That is, based on the water depth of flood, made use of the connectivity with the outfall to calculate the range of water logging, and then implemented the urban waterlogging flood simulation deduction. The test indicated that, this method can implement the evolution of urban waterlogging scenario deduction effectively. And the correlational research could provide scientific basis for urban disaster prevention and emergency decision-making.

Terrain Quantization Model Based on Global Subdivision Grid

MENG Li, CHENG Chengqi, CHEN Dong, YANG Weiming

2016, 45(S1):  152-158.  doi:10.11947/j.AGCS.2016.F019

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To solve the current problems in terrain quantization, such as the limitation of grid levels, the difficulties in data organization and management, and other issues, a quadrilateral terrain quantization model based on global subdivision grid is proposed. The model adopts GeoSOT as the spatial reference, and realize the correlation and retrieval of quantization data among different layers based on GeoSOT location identification code, which provides methods of the the quantization procession, the organization and storage, the data aggregation of the vector data and regular grid data.