isprs wg ii/3 chongjun yang [email protected] sept. 15-19th 2003, thailand co-chair of isprs wg...

ISPRS WG II/3

Chongjun [email protected]

Sept. 15-19th 2003, ThailandCo-Chair of ISPRS WG II/3

IRSA/Chinese Academy of Sciences

WG II/3 Terms of References and Activities •Systems for integrating geo-spatial data •Integrated services involving economic, technical and political aspects •Geo-spatial information distribution and accessibility systems using internet •Development and validation of end-to end spatial data access systems• Liaison with CEOS WGISS and other relevant organizations

ISPRS Working Group II/3

Integrated Systems for Spatial Data Management

http://www.digitalearth.cn/wgII-3

Interoperability of Spatial Data Service

Chongjun [email protected]

Sept. 15-19th 2003, Thailand

Co-Chair of ISPRS WG II/3

IRSA/Chinese Academy of Sciences


For Open System

1. Context 2. Components of Interoperability3. Levels of Interoperability4. Criteria for Interoperable System 5. XML,GML,WMT,C#, .NET6. Example7. Discussion & Cooperation


1. Context : GIS Computing

Computing-Structured(Standlone System)

Computing-Centred(Centre- System)

Client-Server System(Local Network)

Computing-Distributed

System(Intranet/Internet)

Data

Decision

Knowledge

Information

Service

1. Context

Data

1. Context : Trends

Service

GI IT mainstream

1. Context : Interoperable Mechanism of Internet

Internet : TCP/IP

Web: HTML(XML)

HTTP

API

URI

Little interoperability for spatial data

1.Context : Benefits of interoperable spatial data service

(1) eliminating spatial data duplication.

(2) reducing the effort required to manage and maintain spatial data.

(3) facilitating application development activities.

(4) providing a flexible computing environment with access to computing resources ranging from desktop machines to high-performance computers (supercomputers); and

(5) reducing costs associated with data acquisition, management, maintenance, and conversion, model development, and overall operations.

- How should the exchanged data be represented? (data representation)

- How should two systems communicate? (application communication protocol)

- How should data be addressed across systems? (naming mechanism)

- Which functionality should be available between systems? (application programming interface).

2. Components of Interoperability

3. Levels of Spatial Data Service Interoperability

The more the interoperability

mechanism “knows” about the spatial

data, the advanced the degree of

interoperability is.

No knowledge about spatial data

knowledge of the structural (syntactic) aspects of the data

knowledge of the schematic aspect of the data

knowledge of the semantic data aspect

1) DATA KNOWLEDGE

From simple to advanced interoperability:


2) scope of the data model

3) Name Space Management

4) Capabilities of Server API


(1) Decisive interoperability criteria,

(2) Technology criteria, and

(3) Implementation and software criteria.

4. Criteria for Interoperable System

Common data representation: Which data types are supported? level of data representation? is it public? is it a standard?

(1) Decisive Interoperability Criteria

Server interface: which functionality is supported? is it extensible? Is it flexible? is it public? is it a standard?

(1) Decisive Interoperability Criteria

Java

COM/OLE

CORBA/J2EE

GRID

…

(2) Relevant Technology Criteria

Format-to-common format conversion via the data server:

- Availability of software products (is a complete, stable system available?)

- Diverse platform support (is the product available for most platforms?)

- Software maturity

- Support and Maintenance

- Cost of software

- Ease of hosting data via the system

(3) Relevant Implementation and Software Product Criteria

• Recommended by W3C in 1998, XML (eXtensible Markup Language) emerges as the second generation Web language for data interchange on the Web.

• Provides text encoding of all data.• Uses a Document Type Definition or Schema

to ensure document/data consistency.• Over 200 XML derived languages.• Offer real potential to significantly impact

geo-spatial data and systems interoperability on the Web.

5. XML,GML,WMT,C#, .NET: XML

• GML Project launched at OGC meeting, April 1999

• GML provides a standard means to encode Geographic Info in XML.

• GML separates content from presentation. GML is focused on capturing geographic content.

• GML is “styled” into a presentation format such as SVG(Scalable Vector Graphics) for map drawing or other visualizations.

• GML is consistent with existing OGC standards for expressing geographic features.

5. XML,GML,WMT,C#, .NET: GML

GML DataServer

Styling EngineMap Style

Library

HTTP TCP/IP

Stylesheet

Map Viewed inWeb Browser

Graphical rendering

Figure. Process of GML Web Mapping

The Web Mapping Testbed, Phase I, is the first of OGC's

planned Interoperability Initiatives, which involve

sponsors and participants. Federal agency and corporate

sponsors provide funding and a set of objectives related

to geoprocessing interoperability. WMT has so far

demonstrated two types of applications: Web Mapping

Clients, and Web Mapping Servers. The Clients create

requests that satisfy the Web Mapping Protocols.

5. XML,GML,WMT,C#, .NET: WMT

The main interfaces are the GetMap protocol (which

identifies one or more layers to be displayed), the

GetCapability Protocol (which allows the client the

ability to discover the abilities of a server), and finally the

GetFeatureInfo protocol (which allows the client to

uncover the attributes of a displayed feature). Web

Mapping Servers interpret requests that conform to the

WMT protocols and generate appropriate objects that are

returned to the querying clients.

5. XML,GML,WMT,C#, .NET: WMT

C and C++: powerful and flexible, but unproductive

C# — Microsoft solution, a modern, object-oriented

building applications for the new Microsoft .NET

serving both computing and communications

.NET — Internet-based integrated solution

5. XML,GML,WMT,C#, .NET: C#, .NET

6. Example6. ExampleA New Spatial Search Engine

– Enabling the Intelligent Geographic Information Retrieval in Internet

Yuqi,BAI Chongjun YANG Yuqi,BAI Chongjun YANG

Institute of Remote Sensing ApplicationsInstitute of Remote Sensing Applications

Chinese Academy of SciencesChinese Academy of Sciences

http://www.digitalearth.cn

Context:

Using “www.yahoo.com” to search a text

Using “www.mapquest.com” to search a

map

Question:

May we search a map

without using “traditional search engine?

6. Example6. Example

Scenario:

When you are reading news on the web, you maybe meet a place name, for example ‘Afghanistan’, and want to know where it is. Can you just simply select this place name and get the corresponding map?


a.Design of a ‘New Spatial Search Engine’-1

Compatibility

Data Sharing

Modularity

Component Sharing

Interoperability

Service SharingThree Stages:

<-



Design goals Automation:

get command -> query -> render the result Interoperability:

with any web mapping systems Integration:

can be integrated with other existing applications seamlessly and easily.



Conceptual Design Modularization:

For the Web Mapping Systems(WMS) Description:

For the service interfaces of WMS Registration:

a logically centralized, physically distributed registry centre



The Conceptual Architecture

<-


b.Prototype System-1

Geo-coding Service

Map-providing Service


b.Prototype System-2 Software packages used

IBM Websphere UDDI Registry 1.1 VC++ 6.0

Standards SOAP 1.2 UDDI 2.0 GML 2.0


b.Prototype System-36. Example6. Example

b.Prototype System-6

<-


7. Discussion & Cooperation:

a.Would rather provide spatial data service than only data

b.Make all things(hardware,software, data, processing, etc.) as interoperable as possible

c. International cooperation in developing interoperable technology

Thank you!

isprs wg ii/3 chongjun yang [email protected] sept. 15-19th 2003, thailand co-chair of isprs wg...

Documents

spatial data slide

spatial data knowledge

data server

geo spatial data

data model

gml slide

hosting data

data interchange