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DSTT Report OGC & GRID Services DSTT Report OGC Services Allan Doyle NASA/II May 8, 2002 “If you don’t understand first off and it makes your mind go numb, you’re safe to ignore it, it will never work” Dave Winer at InfoWorld Next Generation Web Services Conference, January 2002 Info

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Slide1 l.jpg

DSTT ReportOGC & GRID Services

DSTT ReportOGC Services

Allan Doyle

NASA/II

May 8, 2002


Slide2 l.jpg

“If you don’t understand first off and it makes your mind go numb, you’re safe to ignore it, it will never work”

  • Dave Winer at InfoWorld Next Generation Web Services Conference, January 2002


Slide3 l.jpg
Info mind go numb, you’re safe to ignore it, it will never work”

OGC Services

http://www.intl-interfaces.net/servicemodel

GRID Services

http://www.globus.org/ogsa/


Services time line l.jpg
Services Time Line mind go numb, you’re safe to ignore it, it will never work”

Basic Service Model

Discussion Paper

OpenGIS® Catalog Interface Implementation Specification 1.1

OpenGIS® Catalog Interface Implementation Specification 1.0

Web Registry Services

Discussion Paper

OpenGIS® Abstract Spec

Topic 12 - The OpenGIS

Service Architecture

OGC

Architecture SIG

WWW Mapping SIG

WMT-1

ServicemodelAd Hoc

IP2000 (WMT-2)

IP2001 (OWS-1)

OWS 1.2

J F M A M J J A S O N D

J F M A M J J A S O N D

J F M A M J J A S O N D

J F M A M J J A S O N D

1999

2000

2001

2002

GCMD (SERFs)

NASA

ECHO

CEOS WTF-GOFC

CEOS WTF (??)

Google

ebXML

Industry

Microsoft .NET

UDDI

Grid Services


Technical challenges data vs services l.jpg

Client mind go numb, you’re safe to ignore it, it will never work”

Application

<service name=WMS>

<layer name=“FirePoint”>

<dataURL=ftp://…>

GetMap

WCS

WFS

WMS

Feature

Data

Store

Coverage

Data

Store

Map

Data

Store

Technical ChallengesData vs. Services

  • Search for Services first

    • Decision support community view ?

Develop metadata and discovery mechanisms that can support both service-centric and data-centric modes.

  • Search for Data first

    • Science community view ?

GetFeature

GetCoverage

Service

Catalog

Fusion

Services

Data

Catalog

Geocode

GeoParse

GeoLink

<dataset name=MODIS>

<Online_Resource name=“WMS”>

http://foo.org/wms.cgi?REQUEST=…


Technical challenges metadata vocabularies l.jpg

Interface Type Metadata mind go numb, you’re safe to ignore it, it will never work”

Type Hierarchies

Interface Instance Metadata

Data Type Metadata

Data Instance Metadata

Combinations of Data/Interface

Services & Service Metadata

Controlled Vocabularies

Catalogs & Registries

Interface Type Metadata

Type Hierarchies

Interface Instance Metadata

Data Type Metadata

Data Instance Metadata

Combinations of Data/Interface

End-user

End-user

Services & Service Metadata

Large

Data System

Large

Data System

Controlled Vocabularies

Catalogs & Registries

Coord

Trans.

Coord

Trans.

Catalog

Catalog

Directory

Directory

WMS

WMS

WMS

WMS

i n t e r n e t

i n t e r n e t

WFS

WFS

Service Only

No Data

Service Only

No Data

FTP

FTP

Inventory

Inventory

Catalog

Service

Catalog

Service

Access

Access

Inventory

Inventory

Single Service

Single Service

Data Only

No Service

Data Only

No Service

Multiple Service

Same Data

Multiple Service

Same Data

http://ceos.org

100,50,2

300,75.4

X=56

http://ceos.org

100,50,2

300,75.4

X=56

Technical ChallengesMetadata & Vocabularies

Interface Type Metadata

Type Hierarchies

Interface Instance Metadata

Data Type Metadata

Data Instance Metadata

Combinations of Data/Interface

Services & Service Metadata

Controlled Vocabularies

Catalogs & Registries


Ogc services l.jpg

HTTP GET/POST based interfaces mind go numb, you’re safe to ignore it, it will never work”

Service instances provide their own metadata service descriptions (“Capabilities”) via XML

Filter parameters allow selection of subsets of source data

Output formats advertised by each service instance

http://ceos.org

100,50,2

300,75.4

X=56

OGC Services

WCS

coverage data

WMS

maps

WFS

feature data

<Roads>

<Road>

<gml:name>M11</gml:name>

<gml:centerLineOf>

<gml:LineString

srsName="EPSG:4326">

<gml:coordinates>

0,5.0

20.6,10.7

80.5,60.9

</gml:coordinates>

</gml:LineString>

</gml:centerLineOf>

<classification>motorway</classification>

<number>11</number>

</Road>

</Roads>


Ogc service registry concepts l.jpg

Registry should be able to handle any kind of service. mind go numb, you’re safe to ignore it, it will never work”

Should allow searches against more criteria than WMT-1 catalog

Each service’s metadata should be composed of common elements where possible

Initially described in the IP2000 Basic Service Model

Registry

<Roads>

<Road>

<gml:name>M11</gml:name>

<gml:centerLineOf>

<gml:LineString

srsName="EPSG:4326">

<gml:coordinates>

0,5.0

20.6,10.7

80.5,60.9

</gml:coordinates>

</gml:LineString>

</gml:centerLineOf>

<classification>motorway</classification>

<number>11</number>

</Road>

</Roads>

OGC Service Registry Concepts

Metadata

Metadata

Metadata

WCS

coverage data

WMS

maps

WFS

feature data

<Roads>

<Road>

<gml:name>M11</gml:name>

<gml:centerLineOf>

<gml:LineString

srsName="EPSG:4326">

<gml:coordinates>

0,5.0

20.6,10.7

80.5,60.9

</gml:coordinates>

</gml:LineString>

</gml:centerLineOf>

<classification>motorway</classification>

<number>11</number>

</Road>

</Roads>


Ows1 service model issues l.jpg

Two mind go numb, you’re safe to ignore it, it will never work” competing registry information models: UDDI and ebXML

Two competing means of constructing registries: XML database and OGC Stateless Catalog

Three competing Metadata content models: R4, R7, and R8

Not enough consensus, fragmented results

Registry

<Roads>

<Road>

<gml:name>M11</gml:name>

<gml:centerLineOf>

<gml:LineString

srsName="EPSG:4326">

<gml:coordinates>

0,5.0

20.6,10.7

80.5,60.9

</gml:coordinates>

</gml:LineString>

</gml:centerLineOf>

<classification>motorway</classification>

<number>11</number>

</Road>

</Roads>

OWS1 Service Model Issues

Metadata

Metadata

Metadata

WCS

coverage data

WMS

maps

WFS

feature data

<Roads>

<Road>

<gml:name>M11</gml:name>

<gml:centerLineOf>

<gml:LineString

srsName="EPSG:4326">

<gml:coordinates>

0,5.0

20.6,10.7

80.5,60.9

</gml:coordinates>

</gml:LineString>

</gml:centerLineOf>

<classification>motorway</classification>

<number>11</number>

</Road>

</Roads>


Navigating the web services industry l.jpg

mind go numb, you’re safe to ignore it, it will never work”

W3C

WS-I

Navigating theWeb Services Industry

Standards Organizations

W3C World Wide Web Consortium

OASIS Organization for the Advancement of Structured Information Standards

WS-I Web Services Interoperability Organization

IETF Internet Engineering Task Force

Global Grid Forum

Major Vendors

Microsoft .NET (not an acronym…)

Sun ONE (Open Network Environment)

IBM Websphere (Based on Apache web server)

Acronyms

SOAP Simple Object Access Protocol

UDDI Universal Description, Discovery and Integration

ebXML Electronic Business using eXtensible Markup Language

WSDL Web Services Description Language

OGSA

Open Grid Services Architecture

The Web Services industry

Big players see big money

Much jockeying for position & mindshare

Many overlapping/competing standards

Not many cross-vendor deployments yet

Very complex set of issues(for what seems like a simple concept!)

OASIS

Sun

IBM

Microsoft


Some key points l.jpg
Some key points mind go numb, you’re safe to ignore it, it will never work”

  • Most real, operational web services exist on intranets and extranets.

  • There is little evidence of web services on the “open” internet.

  • Web services are not about “the web”.

  • Web services are producer-oriented tools. Consumers of web services see a carefully controlled entry point. End-users generally see portals.


The eight fallacies of distributed computing how does the grid measure up l.jpg
The Eight Fallacies of Distributed Computing mind go numb, you’re safe to ignore it, it will never work” How does the GRID measure up?

Peter Deutsch

  • Essentially everyone, when they first build a distributed application, makes the following eight assumptions. All prove to be false in the long run and all cause big trouble and painful learning experiences.

  • The network is reliable

  • Latency is zero

  • Bandwidth is infinite

  • The network is secure

  • Topology doesn't change

  • There is one administrator

  • Transport cost is zero

  • The network is homogeneous

  • http://java.sun.com/people/jag/Fallacies.html


  • Wrapping l.jpg

    service mind go numb, you’re safe to ignore it, it will never work”

    Wrapping

    • How hard is it to wrap an OGC service in a GRID wrapper?

    • How hard is it to build OGC services that are clients of GRID services?

    • Can an OGC service be moved to where the data is?

    • Can an OGC service be moved to where the computecycles are available?

    network


    Think of this model l.jpg

    portal mind go numb, you’re safe to ignore it, it will never work”

    GRID

    Web

    Think of this model


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