Moritz Neun Generalization Web Services University of Zurich
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 ondemand 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 Isolated prototypes implemented with different programming languages Integrated within closed monolithic systems (Clarity, Arc. GIS, Genesys, …. ) 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
History
7 History Open architectures based on distributed platforms have attracted significant interest in the generalisation community Lehto and Kilpeläinen (2000, 2001) • XSLT techniques Edwardes et. al (2003) are combined with Java Badard and Braun (2003) Harrieprogramming for realand Johansson (2003) Sestertimeal (2004), et. generalisation Sarjakoski et. al (2005) Burghardt et. al show two • Examples (2005), Neun et. of different XSLT results al (2006, 2007) Regnauld (2006, with different processes 2007) Harrower and Bloch (2006) generalisation Lemmens et al. (2006), functionality Forster and Stoter (2006, (selection and 2007) 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) • Need for a common Badard and Braun (2003) research platform in the domain of map generalisation was expressed Harrie and Johansson (2003) • et. al (2004), Sester Requirements for an open generalisation system Sarjakoski et. al (2005) • Related OGC developments were presented Burghardt et. SLD, SVG, WFS, GML, FES, SOAP, (WMS, al (2005), Neun et. al (2006, 2007) WSDL, …) Regnauld (2006, 2007) Harrower and Bloch (2006) Lemmens et al. (2006), Forster and Stoter (2006, 2007) 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) • OXYGENE platform Harrie and Johansson (2003) developed at the Sester et. al (2004), COGIT laboratory Sarjakoski et. al (2005) of IGN Burghardt et. al (2005), Neun • Based on Java et. al (2006, 2007) technology and Regnauld (2006, 2007) different open source Harrower and Bloch (2006) components Lemmens et al. (2006), Forster. Open. Stoter (2006, 2007) • and 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) • Gi. Mo. Dig (2005), Burghardt et. al services based on layer architecture Neun et. al (2006, 2007) • Layers encapsulating data Regnauld (2006, 2007) integration, data transformation into Harrower and Bloch (2006) GML, data processing Lemmens et al. (2006), Forster(generalisation) and device and Stoter (2006, 2007) dependent styling (portal layer) • Further development of the approach from Lehto and Kilpeläinen with – 19. November 2007 Generalization Web Services – Moritz Neun
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) • Web. Gen 2007) Regnauld (2006, platform • Accessible from different Harrower and Bloch (2006) clients Lemmens et al. (2006), Forster(Web. Stoter (2006, 2007) and 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) • Map. Shaper for browser based generalisation Regnauld (2006, 2007) • Aim on interactive Lemmens et al. (2006), user controlled generalisation, no platform. Forsterindependent (2006, 2007) and Stoter 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. of system architecture for on-demand derivation • Concept (2006), Forster and Stoter (2006, 2007) 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 improvements are expected in the availability of techniques for sharing methods and models. ” Generalization Web Services – Moritz Neun – 19. November 2007
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 services provide 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 Web. Gen framework Generalization Web Services – Moritz Neun – 19. November 2007
State-of-the-Art Toolbox Services
22 State-of-the-Art Toolbox-like service approaches for remote processing open • Web. Gen research platform • Web Processing Services commercial • Arc. GIS Server (ESRI) • Ser. Ax (Axes Systems) Generalization Web Services – Moritz Neun – 19. November 2007
23 Web. Gen § § § Our prototype of a generalisation toolbox service framework Different plug-ins Generic interface descriptions Registry for service discovery Servers for hosting different algorithms 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 a proposal than a real 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 Web. Gen) 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 functions as internal services § Adopts Web. Gen 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 Arc. GIS Geoprocessing Services § Geoprocessing services for the ESRI Arc. GIS Server § All types of geoprocessing tools can be served § Works only with Arc. GIS products and algorithms Rather closed and proprietary commercial system Generalization Web Services – Moritz Neun – 19. November 2007
The Web. Gen Framework
29 kn ow s Implementation of the Toolbox Services Model: § Various different distributed servers can provide generalization services Generalization Server § Generic interface Service descriptions Service § Registry for global service discovery Generalization Server § Services can use Service other services Service (workflow) Registry Server Generalization Web Services – Moritz Neun – 19. November 2007 execute The Web. Gen Framework
30 The Web. Gen Framework Client plug-ins for different platforms Remote processing (execute) JUMP GIS Client Generalization Server Plug-in Local data execute Clarity Client Plug-in Local data Arc. GIS Client es s vic tion er p y s scri er e qu e d ic rv Browser Local data se AJAX Web Client ex Service ec ute Generalization Server Service Registry Server Generalization Web Services – Moritz Neun – 19. November 2007
31 Web. Gen Clients, Registry & Server client server Generalization Web Services – Moritz Neun – 19. November 2007
32 Web. Gen Registry Generalization Web Services – Moritz Neun – 19. November 2007
33 Web. Gen Services Large number of services available! Generalization Web Services – Moritz Neun – 19. November 2007
34 Web. Gen Interface Descriptions Generic XML interface 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 Web. Gen Client-Server Transfer Generalization Web Services – Moritz Neun – 19. November 2007
36 Possible Web. Gen Scenario Workstation Arc. GIS local datasets Registry Server Plug-In Toolbox Plug-In Workstation JUMP local datasets Toolbox Plug-In Arc. GIS Toolbox Server JUMP LAN / Internet Workstation Clarity local datasets Server Arc. GIS Server Plug-In JUMP/JTS Algorithms Server Clarity Server Plug-In Toolbox Plug-In AGENT Algorithms coupling of systems for research or production Generalization Web Services – Moritz Neun – 19. November 2007
Generalization Service Categories
38 Generalization Service Categories Service Consumer service interface interactive interface Process Services (workflow control, evaluation) interactive interface service interface Operator Services Generalization Services (research, map production, …) service interface MRDB interactive interface Support Services (attributes, triangulations …) Generalization Web Services – Moritz Neun – 19. November 2007 Support Services (simplification, aggregation, …)
39 Support Services Provision of auxiliary enriching information (data enrichment) Support Services Entities (geometries, attributes) § § Relations (hierarchical, non-hierarchical) 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) Generalization Web Services – Moritz Neun – 19. November 2007
40 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: Simplification Displacement Removal Generalization Web Services – Moritz Neun – 19. November 2007
41 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 initial simplify typify displace Generalization Web Services – Moritz Neun – 19. November 2007
Discussion
43 Discussion Strengths of the Web. Gen 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-thefly) 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 (Web. Gen is still a prototype) § Advance Web. Gen? § Extend WPS with concrete profile? Generalization Web Services – Moritz Neun – 19. November 2007
Thank you!
47 Web. Gen Registry Generalization Web Services – Moritz Neun – 19. November 2007
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