Proceedings, XXth congress: Proceedings, XXth congress

Altan, M. Orhan

Bibliographic data

Multivolume work

Persistent identifier:: 1663674213

Title:: Proceedings, XXth congress

Sub title:: Istanbul, 12 - 23 July 2004

Year of publication:: 2004

Place of publication:: Istanbul

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 1663674213

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist aus dem Copyrightjahr ermittelt.; Auch bezeichnet als XXth International Congress for Photogrammetry and Remote Sensing

Editor:: Altan, M. Orhan

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Document type:: Multivolume work

Volume

Persistent identifier:: 166368779X

Title:: Proceedings, XXth congress

Scope:: IV, 226 Seiten

Year of publication:: 2004

Place of publication:: Istanbul

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 166368779X

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(35,B8)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist aus dem Copyrightjahr ermittelt.

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Altan, M. Orhan

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: DESIGN SPATIAL CACHE FOR WEBGIS LUO Yingwei, WANG Xiaolin and XU Zhuoqun

Document type:: Multivolume work

Structure type:: Chapter

il 2004 es in ) and essed p the s the ighest Also have been sitive ectral 1995 lation lation 0 soil lation high ble to | with cover NSES, 4. In tance tly to forest R. S. . and t TM on of . No. TM+ atural and t and tional T. les of thesis Isides mbia, m of ige of ial of nding with 23-13 DESIGN SPATIAL CACHE FOR WEBGIS LUO Yingwei *, WANG Xiaolin and XU Zhuoqun Dept. of Computer Science and Technology, Peking University, Beijing, P.R.China, 100871 — lyw@pku.edu.cn KEY WORDS: Component, WebGIS, Geo-Union, Spatial Cache Framework ABSTRACT: À spatial cache framework is designed and adopted in a component based WebGIS system Geo-Union to improve its performance in network environment. The spatial cache framework includes three typical cache modes: database cache, network cache and cache server (data proxy server). 1. INTRODUCTION: GEO-UNION Geo-Union is a GIS platform developed by spatial information lab in dept. of computer science and technology, Peking University. Geo-Union has a multi-level Client/Server architecture, which is implemented by principle of ORDB and component techniques. Geo-Union provides an object-oriented, extensible GIS component library for further GIS application developers. Geo-Union can be used in both stand-alone environment and network environment. Component model is a primary approach to deepen the functions of WebGIS (Bin Li, 2001). To make the system more clear, Geo-Union can be divided into four layers: Geo-Union application layer, Geo-Union component layer, Geo-Union service layer and Geo-Union storage layer, where service layer has different units to provide both client services and server services. Figurel shows the architecture (Dept. of Computer Science and Technology, Peking University, 2002). Hierarchical spatial component object model can distribute GIS functions in network reasonably and make the system reusable, as well as provide efficiency approach for further development and integration with other Systems. Geo- Union Application Layer | A Geo-Union Th 7 Client Siete AT ENS 1 - Geo- Union / AN B Component Las Layer CONCERN. NS ; 1i Y fm Netw ork Geo-Union Service Layer NS: eu 1 f —— Abu savent T | - Geo- Union Geo-Union | deu Server Storage Layer Figure 1 The Architecture of Geo-Union (1) Storage layer is the ground of Geo-Union. Storage layer is responsible for storage and management of both spatial data and non-spatial data based on ORDB. The main problems solved at this layer are how to represent and store spatial data, and how to maintain relationships among spatial data. (2) Service layer is in charge of spatial data access and process, which can be divided into another two parts: Geo-Union client provides data access and process services to component layer, * Corresponding author: LUO Yingwei, lyw@pku.edu.cn. 201 and Geo-Union server provides data access and process services to Geo-Union client through interacting with storage layer. Geo-Union server can manage different spatial data resources, and also can reply to different spatial data requests from different clients. Geo-Union client and Geo-Union server are two independent parts but have close relationship with each other. Geo-Union server provides the services of data access, spatial index, basic spatial query, transaction process, data share and so on. Geo-Union client provides different GIS tools and further development functions to component layer based on the services from Geo-Union server. Cache is an important unit of Geo-Union client, which is imported to reduce network load and improve response speed of the system. Using Geo-Union client, we can develop a simulation server, which can reduce network load and improve response speed through its cache. (3) Component layer provides a rich set of services (components) to develop domain-oriented GIS application systems for further developers. Component layer provides interface of GIS functions to users, but the implementation details are completed in service layer. Component layer exists as a component library, and servers as a bridge between users and service layer. Component layer provides function-explicit and reusable interface components for users according to the functions of service layer. (4) The work in application layer is to exploit application systems for different special domains by assembling and integrating Geo-Union components. These application systems can be running both in desktop and network environment. 2. SPATIAL CACHE FOR GEO-UNION Cache is an important technique for improving the performance of system. In Geo-Union, there are two aspects affecting the efficiency of data access: one is the access to database, especially when storing spatial data in ORDB; the other is the transmission of spatial data in network. We take different spatial cache modes to solve these two problems in Geo-Union. 2.1 Spatial Cache Framework Figure 2 is the spatial cache framework in Geo-Union. The spatial cache framework includes three es cache modes: database cache, network cache and cache server (data proxy server).

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