Introduction to Spatial Data Infrastructures
Document Sample
Introduction to
Spatial Data Infrastructures
•
Werner Kuhn
March 14, 2005 SDI Concepcion
Introductions
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Today
Motivation for the course topic through
• an analogy
• a case study
Sketch basic ideas of SDI
Course plan
• Lectures
• Readings
• Practicals
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An analogy: Cooking
Discuss the infrastructure for preparing food
• What do you need?
• Where do you get it?
• Where does it come from?
• Who is involved in the „food chain“?
• Can you cook at a friend‘s home?
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Elements of the cooking infrastructure
Food: contents
Kitchen ware, stove etc.: technology
Cooks, waiters, diners, farmers etc.: people
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Characteristics
Modularity: lots of components
Flexibility: change ingredients, delivery
mode and time, etc.
Openness: add elements (e.g., a
microwave), change food suppliers, etc.
Standards: packaging, stores, stoves, etc.
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Compare with Maps
„cooking“ a map (old style)
• What do you need?
• Where do you get it?
• Where does it come from?
• Who is involved in the „food chain“?
• Can you „cook“ at a friend‘s home or office?
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Yesterday
GIS Specialists
Maps for Users
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Tomorrow
Services for systems and users,
built by Geo- and GI-Scientists
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Business Opportunities
1. More potato sales
• customers: cooks (i.e., service providers)
• small margins
• improved content information (metadata)
2. More restaurants
• customers: those who can afford it
• big margins
• some economies of scale
• multiplier for potato sales
3. Develop mass products/services (chips)
• customers: everybody
• huge margins
• huge economies of scale
• life line for potato growers
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Business requirements
Sales result from uses
Uses occur through services
Services support decisions by content integration
Content integration occurs in services
=> It is all about services, not about data!
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The wrong analogy ?
Multiple sales of products and services
but: multiple sales of data are rare
Complexity of our „potatoes“
but: still need simple products and services
What has all this to do with SDI?
• Market for Geographic Information (GI) requires
infrastructures
• Mass use of GI products is likely
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Other useful analogies
Infrastructures for
• Transportation
• Telecommunication
• Electricity
• Education
• ....
All of these have something to teach us
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So, what is an SDI ?
No official and general definition yet
My own attempt:
An SDI is a coordinated series of agreements on technology
standards, institutional arrangements, and policies that
enable the discovery and use of geospatial information by
users and for purposes other than those it was created for.
Identifying the stake-holders and the subjects of
agreements is the key step
OGC has created the model for the necessary
consensus process.
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Core ideas
Distribution
Coordination
Sharing
Interoperability
Interfaces
Standards
Architecture
Metadata
Policies
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Scopes of SDI
Local
National
Regional
Global
Sectoral
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GSDI = Global SDI
critical to substantial and sustainable development
involvement and support of decision makers at the
highest levels of business, government and
academia (G7 countries, UN Institutions, World
Bank etc.)
requires education and research activities which
transcend the purely technical treatment of spatial
data
So far: conferences and other publications
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Why this change from GIS to SDI ?
Non-usability of GIS
Market growth for GI(S) industry
E-Government initiatives at all levels
Economic pressure to recover investments
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Drivers
The Open Geospatial Consortium (OGC)
ISO TC 211
High-level government initiatives
Regional initiatives (US NSDI, NRW, Emilia
Romagna, Galicia, ...)
In Europe: INSPIRE
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What has changed from old-style GIS ?
Multi-vendor architectures
Multi-source data
Multi-user applications
Multi-organization projects
Diminished control over information use
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Geolibraries
One stop shops
• http://nsdi.usgs.gov (includes international data)
• http://www.geodata.gov
• http://eu-geoportal.jrc.it/ (beta version)
Integration with GIS
• access data and services from your GIS
• based on OGC web service specifications
• e.g., http://www.geographynetwork.com/
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Observations
Lots of data (somewhere)
• rarely connected to infrastructure
• spotty regional coverage
• thematic variety, without ontology
Few services
• single, isolated functionality
• often tied to a database
Lack of business models
• free vs paid
• per use vs licensing
• commercial uncertainty paralyzes markets
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Reference Data
Idea: spatial data provide a common reference
frame for domain information
• examples: administrative boundaries, roads
But:
• which spatial entities should be used as reference?
no theory
practice: see INSPIRE catalog
• need to be well-defined and widely (maybe freely)
available
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The Growing Role of Services
Bottled functionality
(Mass) uses occur through services
Services integrate content for decisions
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Background: Data Abstraction
Data with associated methods define modules
Parnas, D. L. (1972). "On the Criteria to be used in
Decomposing Systems into Modules." ACM Communications
15(12): 1053-1058.
Interfaces in object-orientation
SCOTS in OGC
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SDI, a misnomer
The goal is not „data exchange“, but
sharing of information
Sometimes SDI are also called Geospatial
Information Infrastructures (GII)
But SDI has stuck (NSDI, GSDI etc.)
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An SDI Case Study
German state of North-Rhine Westphalia
18 Mio inhabitants
Highly industrial
Several small IT companies in the GI area
Very heterogeneous GI production
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Success factors
Politicians wanted a show-off project in the
media business
State funding 1999 to 2002
Very active PPP
Life-critical co-opetition between small IT
companies
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GDI Reference model
User model
Business model
Architecture
Process model
model
Implementation
model
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User model
Requirements for GI from user perspective
Specification based on market study
Results: Priorities for action
• B2B
• focus on
Telecommunication
Trade, banks, insurances
• Involve more stake holders (e.g. Municipalities)
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Business model
Specification of value chains
Specification of GI products and services
Neutral coordinating organisation
• Coordinates implementation projects
• Maintains local standards
• marketing of infrastructure
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Process model
Describes technical processes
Links other models
Focus on
• Publishing GI services
• Discover GI products and services
• Purchase
• Assemble GI products on the fly
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Architecture model
Specification of a Service Architecture
In close cooperation with Special Interest
Groups (SIGs)
Based on Web Services:
• Mapping Service
• Catalog Service
• Data Access Services
• e-Commerce Services
Results
• proof-of-concept through GDI Testbeds
(see separate slides)
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Goals of this SDI Course
1. Familiarize yourself with the basic ideas
and terminology around SDI
2. Awareness of some SDI initiatives and of
some key literature
3. Develop skills for project planning and
proposal writing
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Course idea
Three topical blocks
• Technology
• Semantics
• People (institutions, policies)
Each introduced by a lecture
Followed by individual readings
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Course Program
Monday, March 14
• Introduction
• Goals and Schedule
• Collect materials
• Organize groups
• Skim Cookbook and read Chapters 1-2
Tuesday, March 15
• Lecture on Technology
• Read Cookbook Chapters 5-7
• Brainstorm in groups on possible project goals
Wednesday, March 16
• Technology discussion (based on readings so far)
• Read Cookbook Chapters 3-4
• Write „one pager“ on proposal: problem-approach-results
Thursday, March 17
• Lecture on Semantics
• Read Geospatial Semantics paper (first part)
• Write abstract and state of the art for proposal
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Course Program (cont‘d)
Friday, March 18
• Semantics discussion (based on reading)
• Read Geospatial Semantics paper (rest)
• Draft work plan for proposal
Monday, March 21
• Lecture on institutional and policy arrangements
• Read Onsrud et al. chapter
• Finish work plan for proposal (with deliverables)
Tuesday, March 22
• Discussion of Onsrud et al. chapter
• Write time schedule and budget for proposal
• Prepare proposal presentation
Wednesday, March 23
• Review of SDI topic
• Present proposal
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Practicals
SDI need to be implemented to really understand
the problems
Time needed: approximately 3-5 years for around
30-50 technical experts...
for a short course like this:
• there are no „toy SDI“
• lab exercises with web servers often fail
• Alternative: identify research needs and work program
• Combine with soft skills of proposal writing and presenting
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Your task in this course
write a proposal sketch
for research or development project
on a local or regional SDI
in groups of 4 participants
• Manager: organizes, presents, writes abstract
• Engineer: architecture, technical specifications
• Scientist: research questions, literature
• „Moneyman“: budget, funding sources
today: form groups and assign roles
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Materials
To read and discuss during the course:
• Nebert (Ed.): The GSDI Cookbook www.gsdi.org
(excerpts – today: skim and read Chapters 1-2)
• Kuhn: Geospatial Semantics – why, of what, how?
• Onsrud et al.: The Future of the Spatial Information
Infrastructure.
Additional resources throughout the course
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