GIS and Geo-computation for Water Resource Science and Engineering
Geographic information systems (GIS) have had a tremendous impact on the
field of water resources engineering and science over the last few decades.
While GIS applications for water resources can be traced back to the 1970s,
increased computational power, particularly of desktop computers, along with
advances in software have made GIS widely accessible. Water resources
engineers and scientists seek to model the flow of water, suspended and
dissolved constituents in geographic entities such as lakes, rivers,
streams, aquifers, and oceans. Geographic description of the system of
interest is the first step toward understanding how water and pollutants
move through these systems and estimating associated risks to human beings
and other ecological receptors. As GIS deals with describing geographic
entities, they are used quite extensively in conceptualizing water resources
systems. GIS offer spatially coded data warehousing capabilities that are
not found in regular database software. In addition to data storage,
retrieval, and visualization, a wide range of computations can be performed
using GIS. Geoprocessing tasks such as clip, union, and joint can be used to
slice, dice, and aggregate data, which facilitates visualization for pattern
recognition and identification of hot spots that need attention. GIS can be
used to delineate watersheds, the basic unit for hydrologically informed
management of land resources. In addition to qualitative data visualization,
GIS software come with a variety of geostatistical and interpolation
techniques such as Kriging that can be used to create surfaces and fill in
missing data. In addition, these tools can be used to map error surfaces and
assess the worth of additional data collection. GIS software also come
equipped with a wide range of mathematical and Boolean functions that allow
one to manipulate attributes and create new information. Closed-form
analytical expressions can be directly embedded into GIS systems to simulate
system behavior and visualize the response of hydrologic systems (e.g., a
watershed) to natural (climate change) and anthropogenic (urbanization)
factors. Most of this functionality can be carried out using built-in
functionality and without resorting to any programming. In addition, GIS
software come with back-end programming support, which can be used to
automate geoprocessing tasks, write new functions, and add additional
capabilities for hydrologic analysis. The inclusion of time has been a holy
grail of GIS research. Recent software enhancements and database models
allow the inclusion of time stamped data and create animations that depict
how the system has changed over time, allowing one to visualize over the
entire space-time continuum. The idea of performing water resources
computations and modeling within the GIS framework is referred to as
geocomputation and is the primary focus of this book. The book is written to
be as self-contained as possible and is intended as a text for GIS-based
water resources engineering or science courses suitable for upper-level
undergraduate and early graduate students. It can also be used as a
supplemental text in undergraduate and graduate level courses in hydrology,
environmental science, and water resources engineering, or as a stand-alone
or a supplemental text for an introductory GIS class with an understanding
that the book's focus is strongly on water resources issues.
No comments:
Post a Comment