Transcript No Slide Title

Interoperability ‘in-action’ –
perspectives from UK academia
James Reid
GeoServices, EDINA
10 February 2005
Overview
Who we are
• What we do
• Why Interoperability?
• Interoperability in practice
• Concluding remarks/demo
•
EDINA - Who we are
•
A National Data Centre for Tertiary Education since
1995
– based in the Data Library
•
Our mission...
to enhance the productivity of research, learning and
teaching in UK higher and further education
•
Focus is service
e.g. Digimap, EMOL, etc
but also undertake r&D projects  Services
e.g. JORUM, SUNCAT, Shibboleth, Go-Geo!
•
Until recently, main focus has been provision of
services fund by the Joint Information Systems
Committee (or JISC)
Research and geo-spatial data team
•
Largest team within EDINA
1999
– mixture of GIS specialists and
software engineers
•
Highly experienced and skilled
team
– provides advice nationally and
internationally
– active in standards development
– active in GI community nationally and
internationally
First online GI service,
UKBORDERS, launched in 1994
• Demands of the services offered
means team has been at
leading edge of GI service
development in UK
• Strategic move toward
interoperability
Projects
Services
Today
•
Projects
Services
What we do - Some statistics
Digimap
– Until 2002, largest online geospatial database in
the UK (300+m objects)
* in 1999, it took 70 days to load and convert the data
– 17,000 users (30,000 over 4½ years)
– Average 23,000 files downloaded per month,
200,000 maps generated, 10,000 maps printed off
– In 2003, users downloaded over £6.5m worth of
data
UKBORDERS
– 300+ boundary data sets
– 70+ look up tables
– 1200+ downloads per month
– Value to community of key downloads > £1M
Corollary of what we do - Service requirements
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Fast servicing of requests
Scaleable
– accommodates steady or increasing demand
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•
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Robust (our SLD aspires to 98% uptime!)
Maintainable (see next point)
Standardized
– Can easily substitute components for repair, upgrade, etc
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Rapid prototyping and rollout
All above on tight budget 
(An aside: whats the Business case for Interoperability –
Performance? Cost-reduction? Maintainability? RAD?
recent OGC sponsored research suggests that saving money is
not actually perceived as that important!!)
The vision - a SDI for the UK academic community
Web Services
Data
Data
Data
Data
© 2004 OpenGIS Consortium, Inc.
Data Access - a one-stop shop
User
Based on R. Wagner 2002
WWW-Browser
Go-Geo! Portal
WMS Client
WFS Client
WAAS Client
Clients
Services
Catalogue
Service
WMS Service
WAAS Service
WGS Service
Athens
geoX
walk
WMS Service
WAAS Service
WFS Service
GeoData
EDINA
GeoData
Research Council
Institute
Data
set
1
Data
set
2
JISC Data Centre
Security
Zone
Perceived benefits of Interoperability
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Increases the value of existing and future investments
in Information Systems.
Allows portability of data.
Expands choices for vendor alternatives – no vendor
lock-in.
Enables vertical industry segments to unify trading
practices.
Decreases the long-term cost of ownership for
applicable software investments.
Enables leverage of existing skill-sets, i.e., does not
require proprietary training.
Provides a benchmark for software design.
Specific Project aims
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to prove the feasibility of delivering geo-spatial data
using OGC standards;
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to demonstrate ease of use and value added;
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to build support and enthusiasm for further development;
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to stimulate and advance further thinking; and
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to identify major hurdles in full development.
Project Outputs
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A range of OGC based web services (WMS;WFS;WCS)
A basic annotation web service (XIMA) currently
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A series of demonstrator clients to illustrate:
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investigating IBM WBI development kit for Java to develop a
Geoserver (WFS) ‘plugin proxy server‘ to translate requests
– Access to data (see later)
– A teaching focussed use case (Metosat data in
teaching weather forecasting)
– A research focussed use case (based on dynamic
image registration using web services)
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A report on the utility and issues surrounding
implementation of open standards for geospatial data
within the JISC IIE, including an assessment of
security and access authorisation issues
Data access demonstrator – Issues (1)
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Issues:
– Identify what OGC web services available (estimated that
worldwide there are only c.250 public W*S services and
most of these serving only sample or test datasets) see
www.refractions.net/ogcsurvey
* We identified c.20 WMS, 4 WFS, 2 WCS
– Ensure all ‘conform’ to standards (scale hints missing, layer
names cryptic; SRS missing; versioning dialogue issues)
– Need for local registry (meta-information)
– How to rationalise users view with disparate views afforded
by different services (may not be a 1:1 correspondence of
portrayal and data) – ontology?
– Layer control and legend issues
e.g. Legend issues
Example :
GLOBE – Urban extents
GLOBE – Snow height
GLOBE – Road classification
GLOBE – Soil temperature
BUT
<Layer>
<Name>RIVERS</Name>
<Title>Rivers</Title>
<Abstract>Context layer: Rivers</Abstract>
<Style>
<Name>default</Name>
<Title>Default</Title>
<LegendURL width="180" height="50">
<Format>image/gif</Format>
<OnlineResource
xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="http://globe.digitalearth.gov/globe/en/icon
s/colorbars/RIVERS.gif"/>
</LegendURL>
</Style>
</Layer>
ICDES/GlobalMap – GetLegendGraphic
returns a 35*5 pixels – whiteimage!!
As well as representing legends in different ways in the capabilities file, the
images themselves can vary in size and style. Problems can also arise from
similarities between legends, where the same colour is used to mean two or
more things depending on the layer viewed.
Data access demonstrator – Issues (2)
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Issues:
– Latency and asynchronicity (especially if doing lots of
round-tripping)
– Specification clarity e.g. exact definitions of some
operations in Filter Spec, output schema for WMS
GetFeatureInfo; XIMA leaves a lot unspecified ?
– Specification harmonisation – see next slide.
Addressed under OWS Common?
(04-016r5 e.g. WFS 1.1, Catalog 2.0)
– Metadata and sane names
– Variable quality e.g. granularity and precision of data
(you pay for what you get?)
Differences between WFS and WMS capabilities (Nuke Goldstein Oct 2004)
http://www.directionsmag.com/article.php?article_id=686&trv=1
Preliminary conclusions
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More work required than possibly initially anticipated
(though overheads with modern tools is less significant than
was required previously e.g. MMS)
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Building the services as well as the clients!!
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Differences in underlying technologies may impact upon the
degree of support for ‘standards’ (open source vs
commercial)
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Leading edge or bleeding edge?
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Security and DRM issues barely addressed – how do OGC
‘web services’ map into mainstream Web Serices – what
about WS-Security…longer term where does e-Research and
GGF approaches to security fit in?
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Interoperability by definition assumes a minimum of 2
endpoints – providing the services themselves is only half
the story! Still early days…
Demo…
Data ‘browse & grab’ client
Interop servers
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ICEDS
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DEMIS
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GLOBE
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EDINA
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IONIC
(http://iceds.ge.ucl.ac.uk/) - A demonstration service provided by University
College London and ESYS plc, funded by the British National Space Centre, serving SRTM
and Landsat data at full resolution for Africa, the Indian sub-continent and Europe.
(http://www.demis.nl/home/pages/home.htm) – Company providing range
of OGC products and services
(http://www.globe.gov/globe_html.html) - A worldwide hands-on, primary
and secondary school-based education and science program. Provides access to datasets
for download and a WMS server.
(http://edina.ac.uk) National Data Centre serving UK higher and further
education, delivering inter alia geospatial data and service, including OGC based ones
and services.
(http://www.ionicsoft.com/) - Company providing range of OGC products
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