Generalization web services
This presentation is the property of its rightful owner.
Sponsored Links
1 / 47

Generalization Web Services PowerPoint PPT Presentation


  • 87 Views
  • Uploaded on
  • Presentation posted in: General

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

Download Presentation

Generalization Web Services

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Generalization web services

Generalization Web Services

University of Zurich

Moritz Neun


Motivation

Motivation


Motivation 1

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


Motivation 2

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


Motivation 21

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

History


History1

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


History2

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


History3

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


History4

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


History5

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


History6

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


History7

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


History8

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


History9

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


History10

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


Web services

Web Services


Web service technology

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


Middleware generalization services

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


Toolbox generalization services

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

  • Platformindependentservice access

  • Coupling of different generalizationsystems

  • research platform

  • WebGen framework

Generalization Web Services – Moritz Neun – 19. November 2007


State of the art toolbox services

State-of-the-Art Toolbox Services


State of the art

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


Webgen

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


Generalization web services

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


Generalization web services

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


Axpand

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


Arcgis geoprocessing services

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


The webgen framework

The WebGen Framework


The webgen framework1

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


The webgen framework2

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


Webgen clients registry server

WebGen Clients, Registry & Server

client

server

Generalization Web Services – Moritz Neun – 19. November 2007


Webgen registry

WebGen Registry

Generalization Web Services – Moritz Neun – 19. November 2007


Webgen services

WebGen Services

  • Large number of services available!

Generalization Web Services – Moritz Neun – 19. November 2007


Webgen interface descriptions

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


Webgen client server transfer

WebGen Client-Server Transfer

Generalization Web Services – Moritz Neun – 19. November 2007


Possible webgen scenario

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


Generalization service categories

Generalization Service Categories


Generalization service categories1

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


Support services

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


Operator services

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


Process services

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


Discussion

Discussion


Discussion1

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


Service usage scenarios

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


Where to start

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


Thank you

Thank you!


Webgen registry1

WebGen Registry

Generalization Web Services – Moritz Neun – 19. November 2007


  • Login