Geoscience Reference
In-Depth Information
of urban water management. The increasing use of GIS is an outcome of the
realization of the fact that GIS can play an effective role in dealing with spatial
data used in urban water management. Either GIS as a standalone tool or GIS in
conjunction with other tools can be used to solve urban water problems by
processing and analyzing the spatial data. One of the major challenges faced by
GIS use is of having standardized and more accessible databases. Georeferencing is
an important factor in using GIS. A system where GIS is coupled with urban water
management models is stronger and more effective in finding solutions to various
urban water problems. There is ample literature on the development of the use of
GIS and urban water models. Apart from the conventional coupling of GIS and
urban water models certain other tools (for e.g. evaluation tools) may be used in
conjunction with the GIS-urban water model system. Integration of GIS and urban
water management models in specific applications poses many challenges. This
chapter provides a few examples on how some researchers have developed GIS
based water management systems to meet these challenges.
1.2 GIS
GIS as a technology is designed for storing, manipulating, analyzing, and displaying
data in a geographical context (Seth et al.
2006
). GIS efficiently relates geographic
information to attribute data stored in a database. Large volumes of spatial and non-
spatial data can be overlaid and displayed using GIS (Kaden
1993
). According to
Hatzopoulos (
2002
), a GIS system is a database of all geometric elements of the
geographical space with specific geometric accuracy together with information
(which is in tabular form and related to the geographic location). GIS's range of
abilities comprise of preprocessing data for analysis, spatial analysis and modeling
directly, and post processing results (Goodchild
1993
).
1.2.1 GIS Data
GIS can analyze the spatial data itself or preprocess it for water models which
then can analyze the data as per specific urban water problems. GIS can also process
and display the post modeling data. Spatial data is represented in GIS in vector
format or raster format. In raster data there are rectangles which act as fundamental
units having uniform hydrologic characteristics (Sample et al.
2001
). An example
of raster data would be Digital Elevation Model (DEM). DEMs can be used to study
the surface terrain and also generate contour maps. In case of vector data coordinate
geometry is used to define the unique boundaries of hydrologic characteristics
(Sample et al.
2001
). Vector data comprises of point, polygon, and line. The data
(whether vector or raster) used for GIS analysis and/or urban water modeling
depends entirely on the type of application. Land use maps, DEMs, soil
