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Generalization Web Services

Generalization Web Services. University of Zurich. Moritz Neun. Motivation. Motivation 1.

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Generalization Web Services

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  1. Generalization Web Services University of Zurich Moritz Neun

  2. Motivation

  3. Motivation 1 • Much progress of web cartography through OGC standards. WMS and WFS allow automated access and presentation of cartographic data Pre-calculation and usage of MRDB can support these services only partially • New requirements on delivering and generating on-demand and on-the-fly maps, containing more specific and tailor-made information • OGC (2002) has proposed Feature Generalisation Services, but no further developments yet Generalization Web Services – Moritz Neun – 19. November 2007

  4. Motivation 2 • A large number of generalisation algorithms, auxiliary data structures, cartographic constraints and measures is developed and published Integrated within closed monolithic systems (Clarity, ArcGIS, Genesys, ….) Isolated prototypes implemented with different programming languages Generalization Web Services – Moritz Neun – 19. November 2007

  5. Motivation 2 • Consequences: • Benchmarks and comparison of algorithms difficult • No reuse of available generalisation functionality and support data structures - researchers have to start from scratch • Following that, rarely addressed “advanced questions” on the generalisation process such as combination of several operators, orchestration, … Interoperable (research) platform for sharing of (generalization) functionalities needed Generalization Web Services – Moritz Neun – 19. November 2007

  6. History

  7. History • Open architectures based on distributed platforms have attracted significant interest in the generalisation community • Lehto and Kilpeläinen (2000, 2001) • Edwardes et. al (2003) • Badard and Braun (2003) • Harrie and Johansson (2003) • Sester et. al (2004), Sarjakoski et. al (2005) • Burghardt et. al (2005), Neun et. al (2006, 2007) • Regnauld (2006, 2007) • Harrower and Bloch (2006) • Lemmens et al. (2006), Forster and Stoter (2006, 2007) • XSLT techniques are combined with Java programming for real-time generalisation • Examples show two results of different XSLT processes with different generalisation functionality (selection and simplification) Generalization Web Services – Moritz Neun – 19. November 2007

  8. History • Open architectures based on distributed platforms have attracted significant interest in the generalisation community • Lehto and Kilpeläinen (2000, 2001) • Edwardes et. al (2003) • Badard and Braun (2003) • Harrie and Johansson (2003) • Sester et. al (2004), Sarjakoski et. al (2005) • Burghardt et. al (2005), Neun et. al (2006, 2007) • Regnauld (2006, 2007) • Harrower and Bloch (2006) • Lemmens et al. (2006), Forster and Stoter (2006, 2007) • Need for a common research platform in the domain of map generalisation was expressed • Requirements for an open generalisation system • Related OGC developments were presented(WMS, SLD, SVG, WFS, GML, FES, SOAP, WSDL, …) Generalization Web Services – Moritz Neun – 19. November 2007

  9. History • Open architectures based on distributed platforms have attracted significant interest in the generalisation community • Lehto and Kilpeläinen (2000, 2001) • Edwardes et. al (2003) • Badard and Braun (2003) • Harrie and Johansson (2003) • Sester et. al (2004), Sarjakoski et. al (2005) • Burghardt et. al (2005), Neun et. al (2006, 2007) • Regnauld (2006, 2007) • Harrower and Bloch (2006) • Lemmens et al. (2006), Forster and Stoter (2006, 2007) • OXYGENE platform developed at the COGIT laboratory of IGN • Based on Java technology and different open source components • Open source release in 2005 Generalization Web Services – Moritz Neun – 19. November 2007

  10. History • Open architectures based on distributed platforms have attracted significant interest in the generalisation community • Lehto and Kilpeläinen (2000, 2001) • Edwardes et. al (2003) • Badard and Braun (2003) • Harrie and Johansson (2003)Sester et. al (2004), Sarjakoski et. al (2005) • Burghardt et. al (2005), Neun et. al (2006, 2007) • Regnauld (2006, 2007) • Harrower and Bloch (2006) • Lemmens et al. (2006), Forster and Stoter (2006, 2007) • GiMoDig services based on layer architecture • Layers encapsulating data integration, data transformation into GML, data processing (generalisation) and device dependent styling (portal layer) • Further development of the approach from Lehto and Kilpeläinen with XSLT processing Generalization Web Services – Moritz Neun – 19. November 2007

  11. History • Open architectures based on distributed platforms have attracted significant interest in the generalisation community • Lehto and Kilpeläinen (2000, 2001) • Edwardes et. al (2003) • Badard and Braun (2003) • Harrie and Johansson (2003)Sester et. al (2004), Sarjakoski et. al (2005) • Burghardt et. al (2005), Neun et. al (2005, 2007) • Regnauld (2006, 2007) • Harrower and Bloch (2006) • Lemmens et al. (2006), Forster and Stoter (2006, 2007) • WebGen platform • Accessible from different clients (Web Browser, JUMP, …) • DEMO Generalization Web Services – Moritz Neun – 19. November 2007

  12. History • Open architectures based on distributed platforms have attracted significant interest in the generalisation community • Lehto and Kilpeläinen (2000, 2001) • Edwardes et. al (2003) • Badard and Braun (2003) • Harrie and Johansson (2003)Sester et. al (2004), Sarjakoski et. al (2005) • Burghardt et. al (2005), Neun et. al (2005, 2007) • Harrower and Bloch (2006) • Regnauld (2006, 2007) • Lemmens et al. (2006), Forster and Stoter (2006, 2007) • MapShaper for browser based generalisation • Aim on interactive user controlled generalisation, no platform-independent coupling of generalisation services • Strong relation of user interface and generalisation functionality (limited flexibility - new generalisation functions requires new client versions) Generalization Web Services – Moritz Neun – 19. November 2007

  13. History • Open architectures based on distributed platforms have attracted significant interest in the generalisation community • Lehto and Kilpeläinen (2000, 2001) • Edwardes et. al (2003) • Badard and Braun (2003) • Harrie and Johansson (2003)Sester et. al (2004), Sarjakoski et. al (2005) • Burghardt et. al (2005), Neun et. al (2005, 2007) • Harrower and Bloch (2006) • Regnauld (2006, 2007) • Lemmens et al. (2006), Forster and Stoter (2006, 2007) • Concept of system architecture for on-demand derivation systems • Usage of Geo-Ontologies to formalise input data, user requirements, cartographic knowledge and service descriptions Generalization Web Services – Moritz Neun – 19. November 2007

  14. History • Open architectures based on distributed platforms have attracted significant interest in the generalisation community • Lehto and Kilpeläinen (2000, 2001) • Edwardes et. al (2003) • Badard and Braun (2003) • Harrie and Johansson (2003)Sester et. al (2004), Sarjakoski et. al (2005) • Burghardt et. al (2005), Neun et. al (2005, 2007) • Harrower and Bloch (2006) • Regnauld (2006, 2007) • Lemmens et al. (2006), Forster and Stoter (2006, 2007) • Implementation based on OGC Web Processing Services • Usage of profiles to describe syntax and the semantics of the operation Generalization Web Services – Moritz Neun – 19. November 2007

  15. History • Open architectures based on distributed platforms have attracted significant interest in the generalisation community • Lehto and Kilpeläinen (2000, 2001) • Edwardes et. al (2003) • Badard and Braun (2003) • Harrie and Johansson (2003)Sester et. al (2004), Sarjakoski et. al (2005) • Burghardt et. al (2005), Neun et. al (2005, 2007) • Harrower and Bloch (2006) • Regnauld (2006, 2007) • Lemmens et al. (2006), Forster and Stoter (2006, 2007) Generalization Web Services – Moritz Neun – 19. November 2007

  16. History • M.F. Goodchild (2005). GIS and modeling overview.In D.J. Maguire, M. Batty, and M.F. Goodchild, editors, GIS, Spatial Analysis, and Modeling. Redlands, CA: ESRI Press, pp. 1–18. • “There is also increasing interest in providing basic GIS services, such as geocoding, as remotely invokable methods implemented on the Web. In the next few years,dramatic improvementsare expected in the availability of techniques for sharing methods and models.” Generalization Web Services – Moritz Neun – 19. November 2007

  17. Web Services

  18. Web Service Technology • Generalization Services are Web Services: • Client-Server structure • Component architecture: - encapsulation of functionalities and resources - generic interfaces (interface description) - loosely coupled by contract • Platform independence: usage of standard web protocols (HTTP and XML) • Interoperable Remote Procedure Calls (RPC) (remote processing instead of data delivery)  Web Services are enabling interoperability Generalization Web Services – Moritz Neun – 19. November 2007

  19. Middleware Generalization Services • Typical on-demand or on-the-fly generalization service for web map services: • Used in combination with data services (e.g. WFS) • Translator or compiler for converting and combining datasets in order to be displayed • Usually bound to one or multiple specific and predefined data delivery services Generalization Web Services – Moritz Neun – 19. November 2007

  20. Toolbox Generalization Services • Various processing servicesprovide their functionalities as distributed toolbox • Data to be processed is provided by the user • Everybody can present own services • Platform independent service access • Coupling of different generalization systems • research platform • WebGen framework Generalization Web Services – Moritz Neun – 19. November 2007

  21. State-of-the-Art Toolbox Services

  22. State-of-the-Art Toolbox-like service approaches for remote processing open commercial • WebGen research platform • Web Processing Services • ArcGIS Server (ESRI) • SerAx (Axes Systems) Generalization Web Services – Moritz Neun – 19. November 2007

  23. WebGen • Our prototype of a generalisation toolbox service framework • Different plug-ins • Generic interfacedescriptions • Registry forservice discovery • Servers forhosting differentalgorithms Generalization Web Services – Moritz Neun – 19. November 2007

  24. WPS • Web Processing Service (OGC Draft) • Intended for many purposes not only generalisation • Raster and vector data • Very open (and vague) definitions of interface descriptions and data formats • Currently rather aproposal than areal standard  More concrete profile needed for generalization WPS Concepts from Foerster (2006) Generalization Web Services – Moritz Neun – 19. November 2007

  25. WPS • Foerster (2006) shows WPS implementation for generalisation(partially adopted from WebGen) • Intended for working together e.g. with a web map server like geoserver but not as middleware (geoserver calls the WPS) • Provides ready generalised maps to the requesting client Generalization Web Services – Moritz Neun – 19. November 2007

  26. axpand • Generalsation functionsas internal services • Adopts WebGen concepts(registry & interface descriptions) • possible use of external services • Management of service workflows • Data is not sent in the service calls (remains in central database, only references are passed)  Uses service concept but rather closed and proprietary Generalization Web Services – Moritz Neun – 19. November 2007

  27. ArcGIS Geoprocessing Services • Geoprocessing services for the ESRI ArcGIS Server • All types of geoprocessing tools can be served • Works only with ArcGIS products and algorithms  Rather closed and proprietary commercial system Generalization Web Services – Moritz Neun – 19. November 2007

  28. The WebGen Framework

  29. Generalization Server Generalization Server Service Service Service Service Service Service Service Service Registry Server Generalization Server The WebGen Framework • Implementation of the Toolbox Services Model: • Various different distributed servers can provide generalization services • Generic interface descriptions • Registry for global service discovery • Services can use other services (workflow) knows execute Generalization Web Services – Moritz Neun – 19. November 2007

  30. JUMP GIS Client Generalization Server Generalization Server Plug-in Service Service Service Service Local data Service Service Service Service AJAX Web Client Clarity Client Plug-in Browser Local data Local data ArcGIS Client Registry Server Generalization Server The WebGen Framework • Client plug-ins for different platforms •  Remote processing (execute) execute execute query services service descriptions Generalization Web Services – Moritz Neun – 19. November 2007

  31. WebGen Clients, Registry & Server client server Generalization Web Services – Moritz Neun – 19. November 2007

  32. WebGen Registry Generalization Web Services – Moritz Neun – 19. November 2007

  33. WebGen Services • Large number of services available! Generalization Web Services – Moritz Neun – 19. November 2007

  34. WebGen Interface Descriptions • Generic XMLinterface descriptions: • Nothing predefined in the clients • Dynamic adding of new services • Powerful also for complex interfaces Generalization Web Services – Moritz Neun – 19. November 2007

  35. WebGen Client-Server Transfer Generalization Web Services – Moritz Neun – 19. November 2007

  36. Server Clarity Server JUMP Server ArcGIS Workstation JUMP Workstation Clarity Workstation ArcGIS Server Plug-In Server Plug-In Server Plug-In JUMP/JTSAlgorithms ArcGIS Toolbox AGENTAlgorithms local datasets local datasets local datasets ToolboxPlug-In ToolboxPlug-In ToolboxPlug-In Possible WebGen Scenario Registry LAN / Internet  coupling of systems for research or production Generalization Web Services – Moritz Neun – 19. November 2007

  37. Generalization Service Categories

  38. interactive interface interactive interface interactive interface service interface service interface service interface Operator Services (simplification, aggregation, …) Process Services (workflow control, evaluation) Support Services (attributes, triangulations …) Generalization Service Categories Service Consumer (research, map production, …) Generalization Services Support Services MRDB Generalization Web Services – Moritz Neun – 19. November 2007

  39. Support Services • Provision of auxiliaryenriching information(data enrichment) • make structural knowledge explicit • can be exploited by other services  differentiation by the output data type • simple entities (geometries / attributes) • complex relations (hierarchical / non-hierarchical) Support Services Entities (geometries, attributes) Relations (hierarchical, non-hierarchical) Generalization Web Services – Moritz Neun – 19. November 2007

  40. Simplification Displacement Removal Operator Services • Operator services are implementing concrete generalization algorithms • Perform geometrical and semantical transformations of map objects • Can be context dependent by using structural knowledge (from support services)  Examples from building generalization: Generalization Web Services – Moritz Neun – 19. November 2007

  41. initial simplify typify displace Process Services Workflow / orchestration of different services predefined batch workflows, adaptive workflows and fully automated systems: • Selection of the appropriate algorithms (operator services) for a situation • Use of the right parameter values • Application of operators in the proper sequence Generalization Web Services – Moritz Neun – 19. November 2007

  42. Discussion

  43. Discussion • Strengths of the WebGen approach • Provision of various functionalities as interoperable toolbox (research platform) • Functional subdivision of generalization in support, operator and process services • Sharing, coupling and reuse of functionalities at very different levels of granularity • Provision of complex spatial data structures • Central registry for service discovery • Generic interfaces allow real interoperability • Parallelization possible (clustering) Generalization Web Services – Moritz Neun – 19. November 2007

  44. Service Usage Scenarios • Keep in mind that different user types need different functionalities and levels of complexity: • Novice user (planner wants to simplify a map) • Expert user (NMA wants to couple systems) • Researcher (wants to evaluate an algorithm) • Data display (convert data from WFS on-the-fly) Generalization Web Services – Moritz Neun – 19. November 2007

  45. Where to start? • Challenges: • Meet user scenarios • Common generic (XML) service data model • Generic syntactic and semantic interface descriptions needed (service capabilities and requirements) • Granularity (especially of support services, stateless or stateful services) • Some work required (WebGen is still a prototype) • Advance WebGen? • Extend WPS with concrete profile? Generalization Web Services – Moritz Neun – 19. November 2007

  46. Thank you!

  47. WebGen Registry Generalization Web Services – Moritz Neun – 19. November 2007

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