1. Distributed GIS Technology, Components, Applications and Future April 11 2005 Yang Han

2. Agenda Impact of the Internet on GIS Impact of the Internet on GIS GIS Technology: From Centralized to Distributed GIS Technology: From Centralized to Distributed What is Distributed GIS What is Distributed GIS Why do we Need Distributed GIS Why do we Need Distributed GIS Basic Components of Distributed GIS Basic Components of Distributed GIS The Standards for Distributed GIS The Standards for Distributed GIS Applications of Distributed GIS Applications of Distributed GIS Future of Distributed GIS Future of Distributed GIS

3. Impact of the Internet on GIS Change our lives

4. Impact of the Internet on GIS The Internet is a modern information system that connects thousands of telecommunication networks and creates an “internetworking” framework. The dramatic success of the Internet and the popular adoption of TCP/IP pushed the development of telecommunication into a new age.

5. Impact of the Internet on GIS The GIS community also began to utilize the Internet to develop distributed GIS. The GIS community also began to utilize the Internet to develop distributed GIS. Distributed GIS is a research and application area that utilize the Internet and other internetworking systems to facilitate the access, processing, and dissemination of geographic information and spatial analysis knowledge. Distributed GIS is a research and application area that utilize the Internet and other internetworking systems to facilitate the access, processing, and dissemination of geographic information and spatial analysis knowledge. The Internet is affecting GIS in three major areas: The Internet is affecting GIS in three major areas:  GIS data access  Spatial information dissemination  GIS modeling/processing

6. Impact of the Internet on GIS The Internet provides GIS users easy access to acquire GIS data from different data providers. GIS data warehouse and digital libraries are two common forms of Internet data access systems. The Internet provides GIS users easy access to acquire GIS data from different data providers. GIS data warehouse and digital libraries are two common forms of Internet data access systems.  U.S. Geospatial Data Clearinghouse Activities under the Federal Geographic Data Committee (FGDC) has been working to build a distributed archive of information for universal access (http://www.fgdc.gov) http://www.fgdc.gov  Alexandria Digital Library Project funded by the US National Science Foundation established the first distributed library service for spatially referenced data in 1994 (http://www.alexandria.ucsb.edu/ ) http://www.alexandria.ucsb.edu/

7. Impact of the Internet on GIS The Internet also enables the dissemination of GIS analysis results and spatial information to a much wider audience than does traditional GIS. The Internet also enables the dissemination of GIS analysis results and spatial information to a much wider audience than does traditional GIS. Furthermore, the Internet is becoming a means to conduct GIS processing. It enhances the accessibility and reusability of GIS analysis tools by dynamically downloading or uploading GIS processing components. Furthermore, the Internet is becoming a means to conduct GIS processing. It enhances the accessibility and reusability of GIS analysis tools by dynamically downloading or uploading GIS processing components.

8. Impact of the Internet on GIS The rapid expansion of low-cost bandwidth on the Internet The rapid expansion of low-cost bandwidth on the Internet A new generation of Web-enabled desktop computers and mobile devices. A new generation of Web-enabled desktop computers and mobile devices.

9. GIS Technology: From Centralized to Distributed Mainframe GIS Desktop GIS Distributed GIS Mobile GIS Internet GIS

10. GIS Technology: From Centralized to Distributed Mainframe GIS adopted the monolithic computing model; that is, all programs were in the same mainframe computers. User access to GIS data and analysis functions on the mainframe server were through dumb terminals. Mainframe GIS adopted the monolithic computing model; that is, all programs were in the same mainframe computers. User access to GIS data and analysis functions on the mainframe server were through dumb terminals.

11. GIS Technology: From Centralized to Distributed Desktop GIS relies on GIS programs on the desktop computers. It has two categories. Desktop GIS relies on GIS programs on the desktop computers. It has two categories.  The stand-alone desktop GIS has all the GIS functions, user interface, and data in one stand-alone computer.  The LAN-based desktop GIS usually adopts the two-tier client/server model.

12. GIS Technology: From Centralized to Distributed Distributed GIS represents a dramatic departure from the traditional two-tier client/server model. Rather than relying on desktop GIS programs, distributed GIS, when fully implemented, does not necessarily require the user to install GIS programs on the user’s desktop. It relies on the Internet and wireless networks for data from anywhere with Internet access. Distributed GIS represents a dramatic departure from the traditional two-tier client/server model. Rather than relying on desktop GIS programs, distributed GIS, when fully implemented, does not necessarily require the user to install GIS programs on the user’s desktop. It relies on the Internet and wireless networks for data from anywhere with Internet access.  Internet GIS  Mobile GIS

13. GIS Technology: From Centralized to Distributed

14. The mainframe GIS and desktop GIS are traditionally referred to as GISystems, and distributed GIS is referred to as GIServices. The term service here refers to component services; that is, components with certain functions can be downloaded and reassembled together to build larger, more comprehensive services to perform certain tasks. The mainframe GIS and desktop GIS are traditionally referred to as GISystems, and distributed GIS is referred to as GIServices. The term service here refers to component services; that is, components with certain functions can be downloaded and reassembled together to build larger, more comprehensive services to perform certain tasks.

15. GIS Technology: From Centralized to Distributed Traditional GISystems: Traditional GISystems:  Closed, centralized systems that incorporate interfaces, programs, and data.  System is platform dependent and application dependent.  Migrating traditional GISystems into different operating systems or platforms is difficult.  Different GIS applications may require different GIS packages and architecture design.  Every element is embedded inside traditional GISystems and cannot be separated from the rest of the architecture.  Traditional GISystems include mainframe GIS and stand- alone desktop GIS.

16. GIS Technology: From Centralized to Distributed Client/server GISystems or current desktop GIS are based on generic client/server architecture in network design. Client/server GISystems or current desktop GIS are based on generic client/server architecture in network design.  The client-side components are separated from server-side components.  Client/server architecture allows distributed clients to access a server remotely by using distributed computing techniques or database connectivity techniques.  The client-side components are usually platform dependent. Each client component can access only one specific server at one time.  Different geographic information servers come with different client/server connection frameworks, which can not be shared.

17. GIS Technology: From Centralized to Distributed Distributed GIServices Distributed GIServices  The most significant difference is the adoption of distributed- component technology, which can connect to and interact with multiple and heterogeneous systems and platforms and without the constraints of traditional client/server relationship.  Under a distributed GIServices architecture, there is no difference between a client and a server. Each GIS node embeds GIS programs and geodata and can become a client or a server based on the task at hand.  A client is defined as the requester of a service in a network, and a server provides a service.  A distributed GIServices architecture permits dynamic combinations and linkages of data and GIS programs via networking.

18. GIS Technology: From Centralized to Distributed Application Characteristics Mainframe GISDesktop GISDistributed GIS Architectural models MonolithicEthernet era client/server (two-tier) Web client/server (three-tier or n-tier) ClientDumb terminalsDesktop computersWeb client Client Interface-----Fat Graphic User Interface (GUI) clients Web browsers, JavaBeans, ActiveX controls NetworksLocal area networksLANs or WANsThe Internet ServerMainframeData serversWeb servers, application server, GIS server, and data servers Number of accessible servers OneOne or limited fewThousands or more

19. What is Distributed GIS? Internet GIS Internet GIS Distributed GIS Distributed GIS Web-based GIS Web-based GIS Web GIS Web GIS

20. What is Distributed GIS? The Internet is any network composed of multiple, geographically dispersed networks through communication devices and a common set of communication protocols. The Internet is any network composed of multiple, geographically dispersed networks through communication devices and a common set of communication protocols. The World Wide Web is a networking application supporting a HTTP that runs on top of the Internet. The Internet is not synonymous with the World Wide Web. The World Wide Web is a networking application supporting a HTTP that runs on top of the Internet. The Internet is not synonymous with the World Wide Web. The Internet refers to the network infrastructure, while the Web refers to one of many applications that run on top of the Internet. The Internet refers to the network infrastructure, while the Web refers to one of many applications that run on top of the Internet.

21. What is Distributed GIS? Internet GIS Web-based GIS The Internet WWW

22. What is Distributed GIS? Distributed GIS is defined as a network-centric GIS tool that uses the Internet or a wireless net- information, disseminating spatial information and conducting GIS analysis. Distributed GIS is defined as a network-centric GIS tool that uses the Internet or a wireless net- information, disseminating spatial information and conducting GIS analysis.  The client devices could be desktop computers, laptop computers, PDAs, or mobile phones.  The servers could be distributed in multiple locations.  Protocols could be HTTP, WAP, FTP, Common Object Request Broker Architecture (CORBA) protocols, and ODBC libraries.

23. What is Distributed GIS? Distributed GIS Wireless GIS Internet GIS Web-based GIS Other Internet GIS

24. What is Distributed GIS? Distributed GIS is an Integrated Client/Server Computing System Distributed GIS is an Integrated Client/Server Computing System Distributed GIS is a Web-Based Interactive System Distributed GIS is a Web-Based Interactive System Distributed GIS is a Distributed and Dynamic System Distributed GIS is a Distributed and Dynamic System Distributed GIS is Cross-Platform and Interoperable Distributed GIS is Cross-Platform and Interoperable

25. What is Distributed GIS? Distributed GIS is an Integrated Client/Server Computing System Distributed GIS is an Integrated Client/Server Computing System  Distributed GIS applies the dynamic client/server concept on performing GIS data sharing and analysis tasks.  The connections between the client and server are established according to a communication protocol, mainly TCP/IP.  Depending on the amount of processes performed on the client side, the client could be “thick” or “thin”.  In addition, the concepts of client and server are relative; any computer could be both a server if it provides services to other computers and a client if it requests services from other computers.

26. What is Distributed GIS? Distributed GIS is a Web-Based Interactive System Distributed GIS is a Web-Based Interactive System  The distributed GIS relies on the WWW and its add-ons to provide interactively between the user and the distributed GIS programs.  In addition to the interactivity provided by HTML, XML, or WAP, distributed GIS can also handle vector-based GIS data. It enables users to manipulate GIS data and maps interactively over the Internet or wireless networks.  Users can perform GIS functions such as map rendering, spatial queries, and spatial analysis using a Web browser or other Internet-based client programs.

27. What is Distributed GIS? Distributed GIS is a Distributed and Dynamic System Distributed GIS is a Distributed and Dynamic System  Geospatial data are usually distributed across different departments within an organization and among organizations, either on intranets or on the Internet. Distributed GIS can potentially query and extract these distributed databases rather than simply downloading the data directly into the end users’ local machines to combine with local data.  Distributed GIS clients should be able to search, download, and assemble analysis tools on demand. The clients have control over the functions required for a particular task.

28. What is Distributed GIS? Distributed GIS is Cross-Platform and Interoperable Distributed GIS is Cross-Platform and Interoperable  Distributed GIS can be accessed across platforms regardless of what operating system the user is running. The clients of distributed GIS tend to be able to run in a variety of computing environments and platforms.  To be able to access and share remote GIS data and functions, distributed GIS programs require high interoperability. The Open Geodata Interoperability Specification and Geography Markup Language (GML) by the OpenGIS Consortium (OGC) are attempting to lay the ground rules for GIS interoperability.

29. Why do we Need Distributed GIS Uniqueness of Geographic Information on the Internet Uniqueness of Geographic Information on the Internet  Heterogeneous Format, resolutions, scales, times, and domains Format, resolutions, scales, times, and domains  The power of GIS operations/functions The value of geographic information will increase dramatically by providing GIS users with the capability of GIS operations. The value of geographic information will increase dramatically by providing GIS users with the capability of GIS operations.

30. Why do we Need Distributed GIS The disadvantage of the traditional GIS The disadvantage of the traditional GIS  The high price of GIS software package.  Inaccessibility to the Desktop GIS from locations other than the computer on which the desktop GIS software is installed.  Difficult to customize.  Proprietary technology and the lack of interoperability.

31. Why do we Need Distributed GIS Management Perspective Management Perspective  Globalization of geographic information access and distribution.  Decentralization of geographic information management and update

32. Why do we Need Distributed GIS User Perspective User Perspective  The need of distributed GIS processing to cope with increasing size and variety of geospatial data sets  The need for customizable GIS modules for software package specialization  The demand for location-based information from the general public due to the popularity of the Internet and mobile devices

33. Why do we Need Distributed GIS Implementation Implementation  Installation is not necessary

34. Basic Components of Distributed GIS Client Web Server with Application Server Map ServerData Server

35. Basic Components of Distributed GIS The Client The Client  HTML HTML-based client has very limited user interactivity. It is particularly inadequate for users to interface with maps and spatial objects. HTML-based client has very limited user interactivity. It is particularly inadequate for users to interface with maps and spatial objects.

36. Basic Components of Distributed GIS The Client The Client  DHTML Uses client-side scripting like JavaScript or VBScript to make the plain HTML dynamic Uses client-side scripting like JavaScript or VBScript to make the plain HTML dynamic  ActiveX controls General component ware that can plug into any application that supports Microsoft’s Object Linking and Embedding (OLE) standard. General component ware that can plug into any application that supports Microsoft’s Object Linking and Embedding (OLE) standard.  Java Applets Reside at the Web server and are downloaded from the server and executed on the client at runtime. They allow the user to interact directly with the spatial features on the map. Reside at the Web server and are downloaded from the server and executed on the client at runtime. They allow the user to interact directly with the spatial features on the map.  Plug-ins Software executables that run on the browser to extend the capabilities of Web browsers. Software executables that run on the browser to extend the capabilities of Web browsers.

37. Basic Components of Distributed GIS Web Server and Application Server Web Server and Application Server  Web Server (HTTP Server) Respond requests from clients  Sending existing HTML document or ready-made map images to the client  Sending Java applets or ActiveX controls to the Web client  Passing requests to other programs and invoking other programs such as CGI that could process the queries

38. Basic Components of Distributed GIS Web Server and Application Server Web Server and Application Server  Application Server Translator or connector between the Web server and the map server  Establishing, maintaining, and terminating the connection between the Web server and the map server  Interpreting client requests and passing them to the map server  Managing the concurrent requests and balancing loads among map servers and data servers  Managing the state, transaction, and security

39. Basic Components of Distributed GIS Map Server (GIS Server, spatial server) Map Server (GIS Server, spatial server) A major workhorse component that fulfills spatial queries, conducts spatial analysis, and generates, and delivers maps to the client based on the user’s request. A major workhorse component that fulfills spatial queries, conducts spatial analysis, and generates, and delivers maps to the client based on the user’s request.  Filtered feature data that are sent to the client program for user manipulating  A simple map image in a graphic format, such as GIF or JPEG, or a graphic element map that is composed of discernible map elements with predefined colors, styles, legends, and so on.

40. Basic Components of Distributed GIS Data Server Data Server  Serves data, spatial and nonspatial, in a relational or nonrelational database structure.  A client application such as a Web client or a map server gains access to the database through the SQL. Therefore, a database server is often referred to as a SQL server.  Database middleware is often used to access different databases. There are three major database middleware: ODBC, Java Database Connectivity (JDBC), and Object Linking and Embedded Database (OLE DB) ActiveX Data Object (ADO). Through SQL, ODBC, or JDBC drive, the client application can query, retrieve, and even modify database records in the database server

41. Basic Components of Distributed GIS Client Web Server with Application Server Map ServerData Server

42. Basic Components of Distributed GIS thin client architecture thin client architecture VS. thick client architecture

43. Basic Components of Distributed GIS Major advantages of this model are: 1. Central control 2. Easy for data managing 4. Generally cheaper 5. Integration possibilities Disadvantages are: 1. Response time low 2. Less interactive 3. Vector data does not appear in client side Thin

44. Basic Components of Distributed GIS Thick Major advantages of this model are: 1. Images are not restricted to GIS and JPEG 2. Vector data can be used 3. More functions are available on the client side And disadvantages to this architecture are: 1. Platform and browsers are incompatible 2. Users are required to install additional software

45. The Standards for Distributed GIS Open GIS by Open GIS Consortium (OGC) Open GIS by Open GIS Consortium (OGC) ISO/TC 211 by Technical Committee tasked by the International Organization for Standardization (ISO) ISO/TC 211 by Technical Committee tasked by the International Organization for Standardization (ISO)

46. The Standards for Distributed GIS The main goals of OGC are the full integration of geospatial data and geoprocessing resources in mainstream computing and the widespread use of interoperable geoprocessing software and geodata products throughout the information infrastructure. The main goals of OGC are the full integration of geospatial data and geoprocessing resources in mainstream computing and the widespread use of interoperable geoprocessing software and geodata products throughout the information infrastructure. ISO/TC 211 emphasizes a service-oriented view of geoprocessing technology and a balanced concern for information, application, and system. ISO/TC 211 emphasizes a service-oriented view of geoprocessing technology and a balanced concern for information, application, and system.

47. The Standards for Distributed GIS The OGC, a broad-based alliance of government agencies, research organizations, software developers, and systems integrators, is engaged in a multi-year effort to define open GIS and to develop a set of requirements, standards, and specifications which support it. The OGC, a broad-based alliance of government agencies, research organizations, software developers, and systems integrators, is engaged in a multi-year effort to define open GIS and to develop a set of requirements, standards, and specifications which support it. The overall goal is to encourage software developers and integrators to adhere to these requirements, and through time create tools, databases, and communications systems that maximize the utility of systems and resources and take advantage of technological advances. The overall goal is to encourage software developers and integrators to adhere to these requirements, and through time create tools, databases, and communications systems that maximize the utility of systems and resources and take advantage of technological advances. OGC

48. The Standards for Distributed GIS Major areas of research and development within OGIS include defining a geodata type hierarchy that comprises simple and complex features, maps and coverages, images, and field datasets (and specifying the relevant interfaces); developing a consistent approach to metadata to support data collections and browsing; enabling the concept of ‘‘information communities’’ which share common definitions, information semantics, and data dictionaries/thesauri; and defining the basic data structures required for implementation. Major areas of research and development within OGIS include defining a geodata type hierarchy that comprises simple and complex features, maps and coverages, images, and field datasets (and specifying the relevant interfaces); developing a consistent approach to metadata to support data collections and browsing; enabling the concept of ‘‘information communities’’ which share common definitions, information semantics, and data dictionaries/thesauri; and defining the basic data structures required for implementation. OGC

49. The Standards for Distributed GIS The three broad requirements for Open GIS The three broad requirements for Open GIS  Interoperable applications  Shared data space  Heterogeneous resource browser An open GIS architecture must provide robust methods for accessing multiple forms of data using multiple software environments. An open GIS architecture must provide robust methods for accessing multiple forms of data using multiple software environments. OGC

50. The Standards for Distributed GIS Open GeoData Interoperability Specification (OGIS) Open GeoData Interoperability Specification (OGIS)  initiated by the Open Systems Foundation  a comprehensive object based framework to support distributed access to geodata and geoprocessing resources  The OGC was set up to oversee the development of the OGIS OGC

51. The Standards for Distributed GIS Geography Markup Language (GML)   GML is an XML encoding for the modeling, transport and storage of geographic information including both the spatial and non- spatial properties of geographic features.   The key concepts used by GML to model the world are drawn from the OGC Abstract Specification OGC

52. The Standards for Distributed GIS OGC

53. Applications of Distributed GIS Data Sharing Data Sharing  Put the raw data in the original format along with the metadata in their own Web site.  Join a data clearinghouse network or a GIS data portal and list your data using the same standard or protocol of that data clearinghouse network or GIS data portal.  Put data in a standard format like GML and make it available on the Web.

54. Applications of Distributed GIS Geospatial Information Disseminations Geospatial Information Disseminations  Easier to disseminate information such as land use plans, zoning information, environmental information, and traffic information.  Foster information sharing and exchange among different departments within an agency or across agencies

55. Applications of Distributed GIS Online Data Processing Online Data Processing  Move analysis tools from desktop to online  User-friendly Web browsers interface makes the GIS analysis tools easier to use  Component-based distributed GIS architecture allows the development of interoperable geospatial analysis tools as individual and sellable geoprocessing components

56. Applications of Distributed GIS Location-Based Services (LBSs) Location-Based Services (LBSs)  real-time information  Mobile GIS + GPS

57. Future of Distributed GIS Future Impact Future Impact  Future Impact on the GIS Industry  Distributed GIServices will exploit the reusability and compatibility of GIS software and data objects  Design of distributed GIServices can help the GIS industry migrate gradually from legacy systems and adopt new technologies  Distributed GIServices will change the development strategies of GIS software vendors and will transform the current monopolized GIS market into an open, competitive environment

58. Future of Distributed GIS Future Impact Future Impact  Future Impact on Geographers  Geographers and spatial scientists can build more realistic model to solve their research problems by combine the GIS components and models in distributed GIServices  Distributed GIServices will help scientists and geographers focus on the domain of problems rather than the mechanism of system implementation  The flexible data approach and the operational metadata scheme in distributed GIServices will help geographers utilize on-line information more efficiently and facilitate the reusability of geospatial data for geographic research

59. Future of Distributed GIS Future Impact Future Impact  Future Impact on the Public  Provide transparent, ubiquitous GIServices in daily life  Deliver real-time, integrated services for emergency events

60. Future of Distributed GIS Other research topics Other research topics  Geoportals  Interoperability  Web Service technology

61. Interoperability Interoperability is the ability of a system, or components of a system, to provide information portability and inter-application cooperative process control. Two geographical databases X and Y can interoperate if X can send requests for services R to Y on a mutual understanding of R by X and Y, and Y can return responses S to X based on a mutual understanding of S as responses to R by X and Y Standard

62. Geoportal A technical definition of the word ‘‘portal’’ is ‘‘a web site considered to be an entry point to other web locations’’ Append the term ‘‘geo,’’ and the result might be as follows. Geoportal: a web site that presents an entry point to geographic content on the web or, more simply, a web site where geographic content can be discovered. Metadata Metadata

63. Geoportal The US Federal Geographic Data Committees (FGDC) Clearinghouse web sites represent one of the earliest spatial data infrastructure (SDI) web portal initiatives. The FGDC portals were driven by the first US presidential requirement to support the sharing of geographic information, the National Spatial Data Infrastructure or NSDI

64. Questions?