Transcript Use of SIGRID

Interoperable Data Formats
in Production Systems
Dave Denault & Brian Scarlett
IICWG October 2005
Presentation Content
• Defining interoperability
• The advantages of interoperability
• Achieving interoperability;
• Interoperability with sameness
• Interoperability with interfaces
• The need for standards
• Functional requirements;
• Core interchange technologies
• Open Web mapping standards (WMS)
Defining Interoperability
• The International Organization
for Standardization (ISO)
defines interoperability as;
“The ability to communicate, transfer
and process data among functional
units in a manner that requires the
user to have little or no knowledge
of the unique characteristics of these
units.”
Defining Interoperability
• But we will use the less
formal definition of;
“Enable the largest possible
audience to access and integrate
the data with the least amount
of effort and time.”
Reasons for Interoperability
• To simplify the dissemination of data
and services to partners and clients.
• To facilitate improved data usability in
addition to basic accessibility.
• To promote collaboration both within
and external to the organization by;
• Accelerating the research process
• Encouraging knowledge discovery
• Keeping the way clear for “future
questions and approaches”
Reasons for Interoperability
In other words;
• Get the data out there and make it
simple to locate for everyone.
• Make the data as easy to work with as
possible – minimize data handling.
• Document the data sufficiently such
that others can work with the data in
new and unanticipated ways.
Interoperability via Sameness
• A simple solution is to have all data
providers work within the same
technical environment.
• This solution typically requires;
•
•
•
•
•
Use the same commercial software
Use the same applications
Use the same operating systems
Use the same database designs
Use the same internal data formats, etc
Interoperability via Sameness
• Many organizations have
demonstrated that “sameness” can
be impractical…
• More time-consuming to implement.
• Can be difficult to maintain over
time.
• Slower to adapt as business evolves.
• Some business requirements are
unique and support by all data
providers can become a burden.
Achieving Interoperability
• An alternative solution is to support
heterogeneous technical environments
which communicate via “interfaces”.
• Interfaces determine what can pass
in/out of an environment.
• What does this require?
• Standards
• Standards
• And more standards
• These standards must be well-defined
and complete and universal.
Interoperability and the Web
• The World Wide Web (W3 or Web) is a good
example of how standards can work.
• The Web is supported by the WWW
Consortium (W3C) which has the mandate;
• “To develop interoperable technologies to lead
the Web to its full potential.”
• Prior to 1994, incompatible HTML versions
created problems when using Web pages.
• W3C promoted a set of core principles and
components to be supported by everyone.
• W3C helped to create the current Web.
Interoperability for IICWG
• Basic functions required in an
interoperable environment include
• #1:
Core interchange technologies
that define machine-readable and
machine-interpretable data.
• #2:
The deployment of interactive
geospatial data using Internet
accessible and open standards.
Interoperability for IICWG
• #1: Core Interchange Format
• Used between data providers.
• Would also support external
partners such as researchers and
modellers.
• With full metadata, the data is selfdescribing (e.g. MANICE attributes)
• Replaces the multiple exchange
formats used now (e.g. coverages,
shapefiles, ASCII files, etc)
Interoperability for IICWG
• #2: Standards for Interactive
Geospatial Data;
• Used primarily for sharing data with
clients and the public.
• Clients do not need to have expensive
software to use the data (Web
browser is possible)
• Could also be used for sharing data
with partners since most GIS software
can consume these services too.
Core Interchange Format
• Without a core interchange format,
data conversions are often required.
• But reducing the amount of this
manipulation is desirable since;
• Data conversion is costly to
implement and maintain.
• Dataset-specific software is not
always available to all users.
• Data quality can be compromised
during conversion (losses,
alterations, misinterpretations)
Interchange Formats
• SIGRID-3 is an example of an
existing interchange format.
• SIGRID-3 is a specification for;
• Vector data objects (polygons)
• The attributes of data objects
• Metadata for the objects
• Other emerging standards include the
Geographic Markup Language (GML)
• GML uses XML to express geospatial
vector features and their attributes.
Interchange Formats (NAIS)
• Although intended for archival purposes,
SIGRID-3 is being considered as the
interchange format for NAIS.
• Some extensions to the SIGRID-3
specification are being proposed to fulfill
this role within NAIS.
Canadian Ice Service
Internal system
(e.g. ISIS)
Interchange
Format
(e.g. SIGRID-3)
National Ice Center
Internal system
(e.g. SIPAS)
Interactive Geospatial Data
• Standards already exist to provide
simplified access to distributed
geospatial datasets.
• These standards are actively
supported by the Open Geospatial
Consortium (OGC)
• 280+ commercial, government and
research organizations are involved.
• The OGC encourages development of
standards for geospatial content and
processing and exchange.
OGC Web Map Service (WMS)
• Compliance with OGC standards
enables users to exchange and apply
information directly across;
• Different platforms (e.g. UNIX, Microsoft
Windows, Linux, Mac OSX)
• Different applications
• A key aspect of the OGC standards is
that they are “open standards”.
• Open = non-proprietary with free
distribution (i.e. no royalties or fees)
OGC Web Map Service (WMS)
• The Web Map Service (WMS) uses
HTTP, the basic protocol of the of the
Web, to issue requests.
• The response is a conventional
pictorial format such as JPEG or PNG,
allowing standard Web Browsers to
function as client applications.
• Most commercial GIS software and
many free applications/toolkits also
support WMS (or intend to)
OGC Web Map Service (WMS)
• Currently supporting WMS;
• ESRI ArcGIS Desktop (e.g. ArcView, ArcInfo,
ArcExplorer, ArcGlobe)
• ESRI ArcGIS Server-side (e.g. ArcIMS)
• Autodesk MapGuide
• Intergraph GeoMedia WebMap
• The GeoServer Project
As of October 2005:
• IONIC Red Spider Web
61 products fully compliant
• Mapinfo MapXtreme
240+ products being tested
• Oracle MapViewer 10g
• Refractions uDig viewer (GeoInnovations)
OGC Web Map Service (WMS)
Client/Partner/Public
Web Browser
(e.g. Firefox, IE,)
Data Provider:
Internal GIS systems
(e.g. SIPAS, ISIS)
Geospatial
Data
Stores
(e.g. Geodatabase,
Shapefiles, …)
Web Server
compliant with
OGC WMS
No plug-ins
required
External GIS systems
(e.g. ArcGIS) and
Viewers (e.g. uDig)
Local layers
+
WMS layers
OGC Web Map Service (WMS)
Access to Geospatial Data
Indirect Access to Geospatial Data
Client or
Partner or
Public
Combination Access
to Geospatial Data
Web Server
(WMS)
Web Server
(WMS)
Web Server
(WMS)
GeoSpatial Data
Geospatial Data
Geospatial Data
Summary
• Interoperability encourages the
distribution and access of data with a
minimal amount of user effort.
• The basis for interoperability is
standards, as shown by the Web.
• Interchange formats would support
system-to-system flows of data.
• Web mapping standards (e.g. OGC
WMS) would support system-to-user
flows of data.
www.opengeospatial.org
www.esri.com/software/standards
www.refractions.net
Interoperable Data Formats
in Production Systems
Thank you
Interoperability Presentation
SIGRID-3
Shapefiles
From
Canadian Ice
Service
Web Server
compliant with
OGC WMS
External GIS Viewer
Refractions uDig
The GeoServer
Project
External GIS systems
ESRI ArcGIS 9.1
Local Data:
Shapefiles
Coverages
Imagery
External Web
Server
compliant with
OGC WMS