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1 Local Spatial Data Infrastrutures Based on a Service-Oriented Architecture Clodoveu Davis Leonardo Lacerda Alves PUC Minas.

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Presentation on theme: "1 Local Spatial Data Infrastrutures Based on a Service-Oriented Architecture Clodoveu Davis Leonardo Lacerda Alves PUC Minas."— Presentation transcript:

1 1 Local Spatial Data Infrastrutures Based on a Service-Oriented Architecture Clodoveu Davis Leonardo Lacerda Alves PUC Minas

2 2 Introduction Sharing large volumes of spatial data is an important task GIS are no longer simple departmental tools Corporate tools Governmental tools Society-oriented applications

3 3 Introduction There is demand for GIS in large computational environments, with a large number of users, spread over numerous locations, and high volumes of data Factors: The fast development of networking technology and the Internet The success of Web-based GIS The wide applicability of mobile and ubiquitous computing

4 4 Introduction GIS has always carried the promise of acting as a common denominator between various data sources Research on interoperability Research on semantics and ontologies This makes much more sense in a widespread and heterogeneous computational environment

5 5 Introduction Many challenges arise when someone tries to share (geographic) information: Data format/data structure issues Data quality issues Content issues Semantics

6 6 Introduction Early solutions included Data translation tools Offline data replication Negotiated semantics through (poor) metadata This led to intensive data redundancy and numerous updating/synchronization problems

7 7 Introduction Data sharing and exchange among several organizations is hard to achieve It involves at least A lot of political negotiation Agreements on standards Agreements on costs and cost sharing Agreements on maintenance....

8 8 Introduction The impact of such data exchange and sharing efforts is very positive We need technology that can make such efforts pay off Easier data access Semantics Less maintenance and synchronization issues Semantics Data usage directly from the source, without translation or replication More applications Free access to base maps Public services Value-added services

9 9 Our proposal Extension of the concept of Spatial Data Infrastructures (SDI) to local data and applications Definition of the architecture and creation of a local, intra-organizational, service-oriented local SDI Most SDIs are national or regional in scope Service-oriented architectures help with interoperability issues

10 10 A Brief History of GeoData Sharing Spatial data transfer standards Spatial data clearinghouses Spatial data infrastructures Geoportals

11 11 Early GIS Dataset creation was really expensive and complex Redundant efforts were commonplace Potential data providers were late adopters of GIS technology Incipient market of data conversion services

12 12 Spatial Data Transfer Standards Only helpful with syntactic problems Data sharing requires An offline semantics agreement, plus Select-export-copy-translate-import, plus Some luck There are a number of proposed standards, but none has achieved widespread acceptance

13 13 Spatial Data Clearinghouses SD Clearinghouses have been described as sites through which a number of services related to spatial data can be accessed The emphasis on services is recent: this concept has been initially implemented as a means to obtain off-the-shelf data

14 14 Spatial Data Clearinghouses The first SD clearinghouse has been created by the FGDC (NSDC) in 1994 Examples include: GIgateway (UK) Nationaal Clearinghouse Geo-Informatie (The Netherlands) Australian Spatial Data Directory In Brazil, the closest we got was the GeoMinas Web Site

15 15 Spatial Data Clearinghouses A 2004 study on national SDCs showed that there is a growing dissatisfaction from users as to the functional capabilities available The study indicates that the focus should be user- or application-oriented, instead of data-oriented

16 16 Spatial Data Infrastructures Evolution from the clearinghouse perspective Infrastructure implies that there should be some sort of coordination for policy formulation and implementation US definition (NSDI): technologies, policies, and people necessary to promote sharing of geospatial data through all levels of government, the private and non-profit sectors, and the academic community

17 17 Spatial Data Infrastructures SDI objectives are similar to the ones pertaining to other kinds of infrastructure Fostering economic development by means of a range of publicly-available, multiple-use goods or services This does not mean that the services are free of charge: do not confuse publicly- available with government-supported

18 18 Spatial Data Infrastructures SDIs should Provide standardized access to data Have multiple participants, in the role of information services providers and/or users Have a broad thematic scope Facilitate data sharing

19 19 Spatial Data Infrastructures Examples National SDI (U.S.) Australian SDI Canadian Geospatial Data Infrastructure Infraestructura de Datos Espaciales de España Sistema Nacional de Informação Geográfica (Portugal)

20 20 Spatial Data Infrastructures Widespread adoption of Internet-based tools allowed the creation of Web portals to multiple geographic information sources Geoportals

21 21 Geoportals Geoportal Web site that presents an entry point to geographic content on the Web Includes tools for The discovery of information sources and content Online access to Web-based applications

22 22 Geoportals Examples Geospatial one-stop (U.S.) National Geospatial Data Framework (UK) EU-Geoportal (INSPIRE project) (E.U.)

23 23 SDI vs. Geoportal SDI Confluence of several different geodata providers Access through specific Web services Requires a repository or catalog of available services Metadata Usage by applications Geoportal An SDI encapsulated by a human-computer interface Should be considered a component of an SDI

24 24

25 25 SDI vs Geoportal The distinction between first- and second-generation SDIs is the emphasis on Web services to grant access to data Encapsulating data from multiple sources using Web services is a wider IS strategy SDI = Service-Driven Infrastructure (Bernard and Craglia 2005)

26 26 Service-based Distributed Systems Architecture Service-oriented architecture (SOA) Involves service providers, service aggegators and service users Users may be human or software clients Available services are listed in directories by providers Aggregators design compositions of rules based on primary services

27 27 SOA

28 28 OWS vs WS There is currently some confusion between OGC Web services (OWS) and W3C Web services (WS) OWS do not necessarily use the usual W3C standards, including SOAP and WSDL Instead of UDDI, OWS propose the use of catalog services OWS have a particular interface for binding OWS use GML, and not plain XML

29 29 OWS vs WS The OGC has specified a range of basic Web services Web Feature Service Web Coverage Service Web Map Service Web Gazetteer Service Web Registry Service/OpenGIS Catalog Service Web Coordinate Transformation Service Web Terrain Service

30 30 Local SDI Most SDI development efforts focus on the usual activities of national mapping agencies, as the usual providers of basic mapping data The richness of local GIS applications indicates that SDIs focused on local data can also be important

31 31 Local SDI Motivation The large number of actors involved in spatial activities in urban areas The wide variety and high detail level of information classes involved in urban applications The potential for fostering new applications on commercially interesting subjects Location-based services Personal routing Convenience shopping...

32 32 Local SDI A local SDI and an urban GIS are very different SDI: widely-available, general-use data, accessible through services GIS: organizational tool, built and operated around a definite set of goals

33 33 Local SDI An urban GIS (maintained by the local government) may or may not become an SDI, depending on how freely the government distributes its information, and on how well other urban data providers are integrated in the maintenance effort

34 34

35 35 Services of Interest for a Local SDI Basemap Personal location Geocoding/address recognition and location Routing service Public transportation system Public services Private services Emergency services

36 36 Services of Interest for a Local SDI The proposed services are rather different from the ones specified for NSDIs It should be possible to chain these services to generate more complete or integrated services Value-added commercial services based on public data Public information of commercial interest available through a fee Coordination of efforts during emergencies and natural disasters

37 37 Conclusions and Future Work This is a work in progress We are currently working to create a prototyping environment for Web services and SOA An undergoing project on geocoding is being reconfigured to work under Web services

38 38 Conclusions and Future Work Our goals include Develop a better understanding of the SDI approach Including performance, privacy, and security concerns Develop a method for the design and implementation of WS/OWS for the SDI Design means to publish metadata on services Study the architectural possibilities for chained Web services Mobile GIS applications

39 39

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