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Internet Map Server (IMS) Technology
With
IMS technology, the spatial information published on the Net
is dynamic. The distribution of geographical information via
Internet allows the integration in real time of data originating
in any part of the world. The user has access to WWW resources,
moves freely through all the information with functional tools,
changes graphic representation online, links graphic elements
with information from databases, and works in real time with
analysis functions.
The
options of exchanging, integrating, or analyzing data in a
new form through the network facilitate, expedite, and favor
the process of decision taking. Users can combine data and
information accessible via Internet with local data, see them,
and make consultations and the pertinent analysis.
This
distributive system of information, compared with tools that
are "stand-alone" or installed in a personal computer,
offers the following advantages, among others:
-
Sharing and exchange of data.
- Access
to applications and tools for analysis and decision taking
for a much more extensive public.
- Facilitates
continued updating of information, helping to reduce redundancies
(duplications) and improving access to databases.
- Facilitates
the updating of applications and disclosed information.
The
IMS architecture comprises three levels:
Client
Applications:
Work environment of the user. Any navigator that supports standard
HTML can act as client. It will also need to support Applet
(Plugin) of Java or ActiveX technology if the services being
accessed contain these components. Through Internet, and with
the navigator as interface, the Client sends requests to the
Server Application to obtain the information that the Client
wants to see, consult, or analyze.
Server Applications: These are responsible
for channeling and attending the operations that the user requests
on the data: ArcView IMS, MapObjects IMS, ArcIMS, MapGuide,
Geomedia, MMS, etc.
Databases: The server applications access
the data that can be stored in files or in spatial databases
(spatial data engine, SDE).
The
Land Use Project has researched the advantages and disadvantages
of the most important map server systems available on the
market: ArcView
IMS (Environmental Systems Research Institute, ESRI),
ArcIMS (ESRI),
MapObjects IMS
(ESRI), and MapGuide
(AUTODESK). Other available systems for the spatial distribution
of data on Internet are GeoMedia Web (INTERGRAPH), MapXTreme
(MapInfo), MMS
(Mapserver), Multiviewer
(OpenGIS Consortium) and GIS
Viewer (University of California, Berkeley).
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In a very few years, the World Wide Web (WWW) has evolved
from a hypermedia system to a complete information platform.
For users of geographical information this means that a lot
of the work that is done on a local computer can be obtained
through Internet. This third step in the development of the
Client-Server technology has made it possible to implement
applications that have allowed us to move forward from prepared
and static documents to an interactive and dynamic platform.
In virtual form, any computer connected to the Internet can
offer a service and, using a navigator such as Netscape or
Internet Explorer, we can access it.
ESRI
Free Software
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