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There is a famous quote from 1977: “There is no reason anyone
would want a computer in their home.—Ken Olson, Founder and CEO
of Digital Equipment Corporation”. Today, we can state it in
this way: “There is no reason anyone could survive without a
computer in their home”. In the current era, not only computers
but also the Internet play a vital role in business life—and
recent developments in mobile technology are also driving people
to more demanding solutions.
Omnipresence is inevitable for companies that operate on
different continents and in different time zones, such as the
GeoTech Group. Every serious organization builds its
communication infrastructure first and then builds everything on
top. Accessing one’s web site takes only a few seconds.
The Internet and pervasive computing has affected all
scientific disciplines, including geomatics.
In almost all of the GIS applications, while providing a
web-based (intranet- or the Internet-) solution to our clients,
it usually reflects the well-known n-tier architecture,
specifically “3-tier”. In this way, we isolate platforms and
their implementation details from each other. The first tier
implements a “user interface” that only contains the
presentation elements, such as buttons, text boxes, labels, list
boxes, etc. The middle tier is “business logic”. This tier
contains all the business logic, functionality, workflows,
access control, etc. The third tier is the “database management
system”. It contains database related structures and
functionality. Please refer to the concept diagram above.
3-tier architecture brings us scalability, flexibility and enhanced
maintainability on deployment. We can add as many components as we need. It only
affects that particular tier and the rest of the application remains intact.
Since tiers are independent and only the communication between them is
important, it is easy to replace your existing database management system with
another vendor, such as SQL Server with Oracle, or vice versa.Changes in business logic do not affect the other parts of the system.
Your user interface will remain the same and your database structure will also
be the same. You need only change the way you implement your business logic! You
can easily replace Java with C# or C++ with PHP, and so on, without any
obligation to rewrite the rest of the code in the other tiers.
Enhanced support for distributed/non-distributed application development.
As
long as you specify how these three tiers will communicate, your application
supports both of the schemes without requiring any major overhaul.The methodology I have tried to depict here is a very well-known and a web-based
GIS application development strategy. According to our clients’ needs, we
sometimes merge some of the tiers; for example, we can employ a methodology of
merging the user-interface with business logic, thereby yielding a 2-tier
implementation.
The possibilities are endless. Our aim, at GeoTech, is to analyze your
requirements in the finest detail to provide you with a rapid, yet
cost-effective design and implementation strategy. |
buz@ags-group.com