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Title
The 3rd ISPRS Workshop on Dynamic and Multi-Dimensional GIS & the 10th Annual Conference of CPGIS on Geoinformatics
Author
Chen, Jun

ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001
312
Preliminary Statistical / Graphical analysis
Model Description
Model Derivation
Model Evaluation
—--M ■ ■ =
Model Validation
Figure 3-2: Model Development Processes
c. Processes.
These are the processes involved in deriving the optimal
model as well as developing the rainfall estimation system.
These include GIS analysis, point rainfall estimation, updating,
and area-average rainfall estimation as indicated in the figure
below:
Figure 3-3: Processes involved in the system.
d. Graphical User Interface (GUI).
It is a menu-driven application to implement the GIS-based
rainfall estimation system. It consists of the functions including
the update of database, point and area-average rainfall
estimation, display of the outputs such as estimates, relief
map and isohyet. In this menu-driven application, the user is
presented with a list of actions from which a choice can be
selected. By following the instructions given by the menus, the
system can be easily assessed by the users. In GIS, this
interface is implemented with the aid of ARC Macro Lanquaqe
(AML).
4. IMPLEMENTATION
4.1 Prototype System Design
Based on the conceptual framework mentioned, the system is
designed schematically as shown in Figure 4-1. The whole
system is composed of four major components namely GIS
databases, rainfall estimation engine, model development, and
user interface. All the four components are interrelated such
that: databases are the foundation to all the other
components, model development and user interface
components involve rainfall estimation engine, and user
interface is based on the optimal model derived in the model
development component. Each of these components is
depicted in the following figures.
Rainfall Estimation
Figure 4.1 : System Design Schematic
4.2 Databases Development
With identified spatial and attribute data in the database
required for the model development, the steps involved in
developing the database is indicated in Figure 4-2.
Figure 4-2 GIS Database Development Steps
4.3 Rainfall estimation Engine
Rainfall estimation method involves the regression analysis of
spatial correlationship of topographic parameters with rainfall
within the area of interpolation. This requires the processes
spatial analysis as well as surface analysis in determining area