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2010-12-05 16:40:57
spatial information infrastructure

Questions for the lecture SII
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  1. What is infrastructure?
    "a substructure or underlying foundation; esp., the basic installations and facilities on which the continuance and growth of a community, state, etc.depends as roads, schools, power plants,transportation and communication systems, etc
  2. What is Information Infrastructure?
    a shared, evolving, open, standardized, and heterogeneous installed base"– Shared resource, foundation for (all) the activities in a community– Evolving continuously– Open in the sense of lack of borders (number of components, users,contributors, developers, .. no beginning/ending)– Heterogeneous – components (HW, data, users,sub-structures ..) are of different kind and characteristic– Standards – prerequisite for combining the heterogeneous parts– Installed base – what is existing and being used
  3. What is spatial information infrastructure?
    ‘infrastructure for spatial information’means metadata, spatial datasets and spatial data services; network services and technologies;agreements on sharing, access and use; and coordination and monitoring mechanisms, processes and procedures, established,operated or made available in accordance with this Directive;
  4. What is a Geographic information system?
    • a set of tools that captures, stores, analyzes, manages, andpresents data that are linked to location(s).
    • – designed for a specific purpose (use cases) and a specificuser group
    • – well managed (configuration, versioning, release cycles,data quality, ..)
    • – typically part of an information infrastructure(networking with other components..)
  5. What is an SII/SDI ?
    • ..base collection of technologies, policies and institutional
    • arrangements that facilitate the availability of and access to spatial data.
  6. A (technical) standard is..
    an established norm or requirement about technical systems.It is usually a formal document that establishes uniform engineering or technical criteria, methods,processes and practices.
  7. Why use Standards?
    • Basis for interoperability of independent components
    • – Optimized value chain
    • – Open standards avoid vendor lock-in
    • Reduced costs for implementing interfaces
    • – Less customization
    • - Improved reusability
    • Enlarges both user communities and developer communities
    • – Improved quality (fastermaturing process
    • – Less costs per unit
  8. HTTP
    • Basis of communication in the Web (between server & client)
    • supports many commands, most important:
    • •GET –requests a representation (e.g. digital copy) of the specified resource
    • •POST –submits data to be processed
  9. Static HTML:
    • •HTML document are predefined on server
    • •Web server sends out documents on request
  10. Dynamic HTML
    • •HTML documents are created on request
    • •Often: data to represent is stored in DB
    • Commonly used today
  11. XML
    • Language for communication between server & server
    • Used to store data
    • software and hardware independent
    • xml tags are not predifined
    • can be defined in a schema
  12. xml based languages for geodata
    • –Geography Markup Language (GML)
    • –Keyhole Markup Language (KML)
    • –OpenStreetMap Format (OSM)
    • –City Geography Markup Language (CityGML)19
  13. XML Schema
    • •Describes structure of XML documents (= instances)
    • •Stored in XML Schema Definition (XSD)
    • filecan be used to formally define new languages/ models–(e.g., GML, KML, SVG etc.)
  14. Motivation for Web Services
    • –Interaction between applications over the Web
    • –Web Services can convert applications into web-applications (or: Web accessible API)
    • –Not only a Web of documents Web of services!
    • –Automated Information Exchange between applications!
  15. What is a Web Service
    • A Web service is a software system designed to support interoperable machine-to-machine interaction over a network.
    • It has an interface described in a machine-processable format (specifically WSDL).
    • Other systems interact with the Web service in a manner prescribed by its description using SOAP-messages,typically conveyed using HTTP with an XML serialization in conjunction with other Web-related standards.
  16. WSDL
    WSDL := Web Service Description Language
  17. SOAP
    • •Originally: Simple ObjectAccess Protocol
    • •Today: not an acronym anymore; just SOAP
    • •Evolvement of remote procedure calls through plainXML (so-called: XML-RPC)
    • •Platform independent
    • •Usually used over HTTP
  18. SOAP Basic Structure
    • SOAP Message
    • Envelope [required]
    • Header [optional] Includes meta information (security, transaction number...)
    • Body [required] Includes the actual message payload
    • Fault [optional] Contains errors and status information
  19. System Architecture (definition)
    • System: A collection of components organized to accomplish a specific function or set of functions.
    • Architecture: The fundamental organization of a systemembodied in its components, their relationships to eachother, and to the environment, and the principles guiding its design and evolution
  20. System Architecture, Main Purposes of an Architectural Description
    • Facilitate planning, managing, and executing the activities of system development
    • • Documenting decisions on high level design issues
    • • Reusing design patterns
    • • ..– Communication amongst the system stakeholders
  21. System Architecture, Typical Stakeholder‘s concerns
    • • Certain functionality– …
    • • Non functional requirements
    • – Performance
    • – Scalability
    • – Robustness
    • – Maintainability
    • – Costs
  22. Cloud-based Architecture
    • • Infrastructure as a Service (IaaS)
    • – Virtualized and dynamically managed (elastic) IT infrastructure
    • – On demand provisioning of resources (server, storage)
    • – Delivers computational infrastructures as services over the network
    • • Platform as a Service (PaaS)
    • – Software development and deployment platform
    • – Quality of Service, QoS (scalability) managed by cloud provider
    • • Software as a Service (SaaS)
    • – Dyncamic Software and data provisioning (outsourcing, on-demand)
    • – Allows pay-per-use revenue models
  23. Chracteristics of the cloud based architecture
    • Characteristics
    • • Virtualization
    • • Ubiquity
    • • Elasticity
    • • Scalability
    • • Reliability, SLA
    • • Pay-per-use
    • • On-demand
  24. How does OGC work?
    • Consensus process–that is reflecting a common understanding of requirements and a membership driven process.
    • Formalised standards development process
    • –based on commonly agreed, structured and well defined policies and processes.
    • •Making use of innovative processes
    • –for testing, verifying and documenting user requirements
  25. OGC Document Types
    • •Public Change Request
    • •Engineering Report
    • •Discussion paper
    • •White paper
    • •Best practice document
    • •Abstract specification
    • •Implementation Standard
  26. OGC Web Services Architecture
    • •Defined on Internet standards: URLs, HTTP, XML
    • •SOA based:
    • •message-oriented, stateless, common elements
    • Publish-find-bind
    • hardware and software neutral
    • •Closely based on ISO 191XX series of standards
    • •Services chaining to support workflow
  27. ISO Topics
    • Topics are organized in working groups
    • –Geospatial service
    • –Imagery–Information communities
    • –Information management
    • –Ubiquituous public access
  28. Geography markup language
    • •a modeling language for geographic information
    • •an encoding for geographic information
    • •designed for the web and web-based services
    • •GML is an OpenGIS® Implementation Specification–Current version is 3.2.1
    • •GML is also published as ISO 19136
    • GML enables a vendor-neutral exchange of spatial data
    • •spatial and non-spatial properties of objects
  29. OGC WMS
    • •Web Service for maps as images on the web–HTTP & XML–JPEG, PNG, GIF
    • •Maps are organized as (nested) layers
    • •Layers from different WMSs can be overlayed
    • •Current version 1.3.0
    • •Published as ISO 19128
  30. OGC WFS
    • •Web Services for feature data on the web–HTTP & XML
    • –GML
    • –Features can be queried by featuretype
    • –Query is expressed through Filter Encoding (ISO 19143)
    • •New version 2.0.0–Previous version
  31. OGC WCS
    • Web Service for coverages on the web
    • –Examples are TINs & GRIDs (see GML Application Schema –coverages)
    • –Different bindings
    • •New version 2.0.0
    • –Former version 1.1.0