Web Service and Geographical Information Integration

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Web Service and Geographical Information
Integration Peking Spatial Applications
Integrating Infrastructure, A Research for
Spatiality-oriented Web Service
Application Lab of Spatial Information
System_at_PKU http//gis.pku.edu.cn lyw_at_pku.edu.cn
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Syllabus

• Introduction of Spatial Application
• Design Intention of Peking Spatial Applications
  Integrating Infrastructure(PAI)
• Web Service-Based Distributed Spatial Information
  Disposition Architecture
• QoS Strategies in Spatial Information Integration
  Disposition
• An Example for PAI-Organized Applications

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Introduction of Spatial Application

• Characteristic of Spatial Information and
  Manipulation Platform
• Spatial information
• Massive
• Long time of data sedimentation
• Multiple spatial data models
• Adhere to certain GIS platform to be accessible
  
• Spatial information manipulation platform
• Data stored in heterogeneous GIS(dominated as
  MapInfo, ArcInfo) platform or inner spatial
  module presented by certain manufacturers(Oracle
  Spatial by Oracle)
• Relevant services, product series based on
  platform self-defined organization
• Single accessible data portal

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Introduction of Spatial Application

• Characteristic of Conventional Spatiality-oriented
  Application
• Direct development of application based on
  platform-critical architecture
• Spatial information visualization, query, and
  edition at the front end based on homogeneous
  data storage at the back end
• Whenever inter-platform integration is needed,
  the writing of application-related adapter
  software for each participating platform is used

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Introduction of Spatial Application

• Challenges imposed by nowadays spatial data
  integration
• Participated by processes running on
  heterogeneous platforms from multiple
  organizations
• Integrating existed spatial application systems
• Implement of dynamic integration accounting for
  on-time subsystem scalability
• Refining of existing services to present QoS
  attributes during integrated service formation
• Semantic level interoperation to obtain
  automatic service communication and assemblage

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Introduction of Spatial Application

• Which we are confronted lies in that
• Prevalent large-scaled spatial
  applications(Digital City, E-Government) call for
  a more flexible, dynamical, semantic integration
  among existing legacy data, system, platform and
  framework.

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Introduction of Spatial Application

• Work of OGC in Improvement of Spatial
  Interoperability
• A common architectural framework for web-based
  geospatial services
• Concentrating on definition of behavior of
  functional components common to all such services
  and extensible for specific services and service
  types
• Specification for distributed computing
  interaction, distributed computing workflow
• Our Emphasis Above-base integration of Web
  Services to obtain dynamic interoperation

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Syllabus

• Introduction of Spatial Application
• Design Intention of Peking Spatial Applications
  Integrating Infrastructure(PAI)
• Web Service-Based Distributed Spatial Information
  Disposition Architecture
• QoS Strategies in Spatial Information Integration
  Disposition
• An Example for PAI-Organized Applications

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Design Intention of PAI

• The main goal of PAI infrastructure is to
  provide open second-time developing platform of
  spatial information application integration
• Provide united sharing mechanism and support
  technologies to access and acquire spatial
  information
• Solve distributing and heterogeneity of spatial
  applications(such as heterogeneity of GIS
  platforms, systems, expression and semantic
  collision)
• Provide interoperation platform for isolated
  spatial applications

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Design Intention of PAI

• Reasons for the construction of PAI based on Web
  Service oriented distributed framework
• Web Service concentrates on fast conformity and
  deployment of legacy systems, which facilitates
  the integration of existing spatial applications
• Web service can separate system implementation
  and function interfaces by function publishing as
  services, which permits flexible function
  replacement in implementation aspect
• Security of sensible data and relevant services
  inside some industries are well protected because
  of the separation between interfaces and
  implementations

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Syllabus

• Introduction of Spatial Application
• Design Intention of Peking Spatial Applications
  Integrating Infrastructure(PAI)
• Web Service-Based Distributed Spatial Information
  Disposition Architecture
• QoS Strategies in Spatial Information Integration
  Disposition
• An Example for PAI-Organized Applications

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Web Service-Based Distributed Spatial Information
disposition Architecture
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Syllabus

• Introduction of Spatial Application
• Design Intention of Peking Spatial Applications
  Integrating Infrastructure(PAI)
• Web Service-Based Distributed Spatial Information
  Disposition Architecture
• QoS Strategies in Spatial Information Integration
  Disposition
• An Example for PAI-Organized Applications

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QoS Strategies in Spatial Information Integration
Disposition

• Problems deserved consideration in current
  integration
• Massive spatial information presented in GML
  format in PAI to ease interaction, while GML is
  pain-text format, which leads to deficiency in
  transmission
• Frequent map retrieval which calls for data
  caches to be maintained both in Adapter Service
  or in Integrating Coordinator(IC) Layer
• Differentiated Services of map to the clients
  which have different network situations and
  application requirements

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QoS Strategies in Spatial Information Integration
Disposition

• Current QoS Strategies in PAI
• GML data compression
• During data transformation client-end
  transmission
• Compression editions maintained in caches of IC
  Layer
• Implementation of cache mechanism flexible to
  multiple spatial data granularities
• Caches by Adapter Service, IC Layer Web
  browsers
• Elaborate selection of content-equivalent data
  providers
• Non-function facets, history records fatal
  parameters of Web services
• Other QoS-related Differentiated Services
• Vector map clipping, On-line map generation

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QoS Strategies in Spatial Information Integration
Disposition
A typical application aided by QoS strategy based
on PAI architecture
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QoS Strategies in Spatial Information Integration
Disposition

• Typical Workflows

Sample API in PAI Toolkits Invoked Web Service Workflow
retrieveMap (MapName) MDS(for layer info adapter service Info) ?Adapter Service(for corresponding GML data of certain layer)
retrieveMapasJPEG (MapName) QoS Consultation Service(for Cache Info) ? (Uncached) MDS ? Adapter Service (Cached) ? Spatial Analysis Service(for on-line JPEG transformation)
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Syllabus

• Introduction of Spatial Application
• Design Intention of Peking Spatial Applications
  Integrating Infrastructure(PAI)
• Web Service-Based Distributed Spatial Information
  Disposition Architecture
• QoS Strategies in Spatial Information Integration
  Disposition
• An Example for PAI-Organized Applications

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Examples for PAI-Organized Applications

• We have implemented the LBS service based on PAI
  framework
• Designed for both mobile terminal and PC
• Provides some location-based services
• finding the nearest service facilities (for
  example banks)
• getting the nearest services facilities
• finding the position of oneself or ones friends
• getting the relevant information about appointed
  position

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Examples for PAI-Organized Applications
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An Example for PAI-Organized Applications
Components of Layers in LBS
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An Example for PAI-Organized Applications
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Another Work in Our Lab
A GML-bases lightweight WebGIS system PKGML
http//map.pku.edu.cn
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Thank You!
Lab of Spatial Information System_at_PKU http//gis.p
ku.edu.cn lyw_at_pku.edu.cn