CoastGIS’99: geomatics and coastal environment
The requirements to implement Distributed Geographic Information
(DGI) cover at least five types of activities:
1. GI metadata held on, and distributed via, the Web (or an intranet).
Problems in creating metadata to emerging standards still exist and must
be overcome in the near future, as well as finding new and better ways
to access the metadata itself;
2. GI data itself distributed via Web servers (Internet or intranet) or via
a combination of CD-ROM data and Internet/intranet connectivity. The
main problems here are related to both the volume of data involved
(especially for raster based images) and “access” barriers, such as legal
restrictions to data use and re-use, pricing schemes, etc.;
3. “Simple” spatial queries from a client that are satisfied on a remote
GI data server, with the answer sent back over the Web (or in-house
intranet) to the client;
4. Complex spatial analyses executed solely on a remote GI server where
both data and applications software are located, the answer being transmitted back to the client via the Internet or an intranet, in response to
a query posed by the client. The client PC normally requires only rather
simplistic Graphic User Interface (GUI) software;
5. Complex spatial analyses executed using both client (local user’s PC)
and remote server application software and data.
Most major GIS vendors now have “GI Web server” capability in their
product lines (Plewe, 1997). Many different types of user are now trying
to use GI via the Web or corporate intranets, but users need considerable expertise and special GIS software to overlay different map layers
of the same geographic region. The Open GIS Consortium(OGC), champions of GIS interoperability, realized that consensus among GIS software vendors would permit such overlays and combinations of complex
and essentially different kinds of geographic information to occur automatically over the Web, despite differences in the vendors’ geographic
data storage, analysis, and display systems. Their Web Mapping Testbed
initiative, involving both vendors and users, was demonstrated to senior
US officials in September 1999- At the demonstration, Thomas Kalil,
Special Assistant to the US President for Economic Policy at the White
House National Economic Council, noted that, “Geospatial information
is critical for disaster management, crime mapping, environmental
monitoring, community decision-making, and a whole host of other
public and private sector applications. The Web Mapping Testbed will
greatly accelerate our ability to access and understand geospatial information from multiple sources.” (McKee, 1999).
The importance of this and similar initiatives was summed up by David
Schell, President ofOGC, noting that ”... as the value ofa Web browser
increases with the size of the Web, the value of a-n on-line GIS or an online collection of geographic data increases with the number of Webbased software systems that can access it through OpenGIS interfaces.
Soon Web users will be able to use their browsers to seamlessly access,
view and exploit the vast, diverse and widely distributed geospatial
33
The requirements to implement Distributed Geographic Information
(DGI) cover at least five types of activities:
1. GI metadata held on, and distributed via, the Web (or an intranet).
Problems in creating metadata to emerging standards still exist and must
be overcome in the near future, as well as finding new and better ways
to access the metadata itself;
2. GI data itself distributed via Web servers (Internet or intranet) or via
a combination of CD-ROM data and Internet/intranet connectivity. The
main problems here are related to both the volume of data involved
(especially for raster based images) and “access” barriers, such as legal
restrictions to data use and re-use, pricing schemes, etc.;
3. “Simple” spatial queries from a client that are satisfied on a remote
GI data server, with the answer sent back over the Web (or in-house
intranet) to the client;
4. Complex spatial analyses executed solely on a remote GI server where
both data and applications software are located, the answer being transmitted back to the client via the Internet or an intranet, in response to
a query posed by the client. The client PC normally requires only rather
simplistic Graphic User Interface (GUI) software;
5. Complex spatial analyses executed using both client (local user’s PC)
and remote server application software and data.
Most major GIS vendors now have “GI Web server” capability in their
product lines (Plewe, 1997). Many different types of user are now trying
to use GI via the Web or corporate intranets, but users need considerable expertise and special GIS software to overlay different map layers
of the same geographic region. The Open GIS Consortium(OGC), champions of GIS interoperability, realized that consensus among GIS software vendors would permit such overlays and combinations of complex
and essentially different kinds of geographic information to occur automatically over the Web, despite differences in the vendors’ geographic
data storage, analysis, and display systems. Their Web Mapping Testbed
initiative, involving both vendors and users, was demonstrated to senior
US officials in September 1999- At the demonstration, Thomas Kalil,
Special Assistant to the US President for Economic Policy at the White
House National Economic Council, noted that, “Geospatial information
is critical for disaster management, crime mapping, environmental
monitoring, community decision-making, and a whole host of other
public and private sector applications. The Web Mapping Testbed will
greatly accelerate our ability to access and understand geospatial information from multiple sources.” (McKee, 1999).
The importance of this and similar initiatives was summed up by David
Schell, President ofOGC, noting that ”... as the value ofa Web browser
increases with the size of the Web, the value of a-n on-line GIS or an online collection of geographic data increases with the number of Webbased software systems that can access it through OpenGIS interfaces.
Soon Web users will be able to use their browsers to seamlessly access,
view and exploit the vast, diverse and widely distributed geospatial
33