Monthly Archives: May 2009

Distributed Hydrologic Modeling Using GIS

Second Edition
by
BAXTER E. VIEUX
School of Civil Engineering and Environmental Science,
University of Oklahoma,
Norman, U.S.A.

©2005 Springer Science + Business Media, Inc

Preface
Distributed modeling is becoming a more commonplace approach to
hydrology. During ten years serving with the USDA Soil Conservation
Service (SCS), now known as the Natural Resources Conservation Service
(NRCS), I became interested in how millions of dollars in construction
contract monies were spent based on simplistic hydrologic models. As a
project engineer in western Kansas, I was responsible for building flood
control dams (authorized under Public Law 566) in the Wet Walnut River
watershed. This watershed is within the Arkansas-Red River basin, as is the
Illinois River basin referred to extensively in this book. After building nearly
18 of these structures, I became Assistant State Engineer in Michigan and,
for a short time, State Engineer for NRCS. Again, we based our entire design
and construction program on simplified relationships variously referred to as
the SCS method. I recall announcing that I was going to pursue a doctoral
degree and develop a new hydrologic model. One of my agency’s chief
engineers remarked, “Oh no, not another model!” Since then, I hope that I
have not built just another model but have significantly advanced the state of
hydrologic modeling.
This book sets out principles for modeling hydrologic processes
distributed in space and time using the geographic information system (GIS),
a spatial data management tool. Any hydrologic model is an abstract
representation of a component of a natural process. The science and
engineering aspects of hydrology have been long clouded by gross
simplifications. Representation by lumping of parameters at the river basin
scale such that a single value of slope or hydraulic roughness controls the
basin response may have served well when computer resources were limited
and spatial datasets of soils, topography, landuse, and precipitation did not
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Enhancing a GIS Cellular Automata Model of Land Use Change: Bayesian Networks, Influence Diagrams and Causality

 

by: Kocabas, Verda1; Dragicevic, Suzana2

Source: Transactions in GIS, Volume 11, Number 5, October 2007 , pp. 681-702(22)
Publisher: Blackwell Publishing

Cellular Automata (CA) models at present do not adequately take into account the relationship and interactions between variables. However, land use change is influenced by multiple variables and their relationships.

The objective of this study is to develop a novel CA model within a geographic information system (GIS) that consists of Bayesian Network (BN) and Influence Diagram (ID) sub-models. Further, the proposed model is intended to simplify the definition of parameter values, transition rules and model structure. Multiple GIS layers provide inputs and the CA defines the transition rules by running the two sub-models. In the BN sub-model, land use drivers are encoded with conditional probabilities extracted from historical data to represent inter-dependencies between the drivers. Using the ID sub-model, the decision of changing from one land use state to another is made based on utility theory. The model was applied to simulate future land use changes in the Greater Vancouver Regional District (GVRD), Canada from 2001 to 2031. The results indicate that the model is able to detect spatio-temporal drivers and generate various scenarios of land use change making it a useful tool for exploring complex planning scenarios.

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Cellular Automata Approach for Flood Forecasting in a Bifurcation River System

by: Tri P.D. VAN 1, Paul A. CARLING 1, Tom J. COULTHARD 2 and Peter M. ATKINSON 1

1 School of Geography, University of Southampton,Southampton, SO17 1BJ, UK
2 School of Geography, University of Hull, Hull, HU6 7RX, UK

A b s t r a c t

Bifurcations in river networks are key components of anastomosing river systems. However, most research has investigated bifurcations in meandering and braided river systems but not in anastomosing ones. In addition, numerical modelling has been mainly conducted for a single reach.
This paper is to investigate the use of a numerical modelling approach (i.e. cellular automata (CA) paradigm) for a large bifurcation in the Mekong River system at the Siphandone Wetlands, Laos. The main characteristics of this river system are: (i) multiple complex channel; (ii) the combination of bedrock and alluvial river bed; (iii) flooding is quite fixed in terms of timing annually but extremely variable in terms of peak discharge; and, (iv) more than 60% of the river banks are unstable.
The CA approach is relatively simple and has the ability to address some of the shortcomings of other types of numerical model. Via a CA model with a proper flow routing scheme, channel dynamics can be accounted, with the relevant prediction of inundation patterns, and water depths. The results show the application of a CA model for predicting the scale of flood inundation according to different scenarios of discharge from upstream. Finally, the discussion is used to argue how to successfully apply a CA model in such a complicated hydraulic system, as a bifurcation pattern.

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Study Of Cellular Automata Models For Urban Growth

by: Nagaratna P Hegde, *Dr I V MuraliKrishna, **Dr K V ChalapatiRao

Associate Professor, CSE Dept, Vasavi College Of Engineering, HYDERABAD-500031

Abstract :
Differential equations, partial differential equations and in some instances,empirical equations have been the underlying mathematical tools behind spatial simulation models. Approaches based on cellular automata models are proposed herein to replace the conventional tools. Issues such as the definition of transition rules, computer implementation with raster geographical information systems and model verification are discussed.

Cellular automata (CA) models consist of a simulation environment represented by a grid of space (raster), in which a set of transition rules determine the attribute of each given cell taking into account the attributes of cells in its vicinities. These models have been very successful in view of their operationality, simplicity and ability to embody both logics- and mathematics-based transition rules. It is thus evident that even in the simplest CA, complex global patterns can emerge directly from the application of local rules, and it is precisely this property of emergent complexity that makes CA so fascinating and their usage so appealing.

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GeoCampus

Forum Komunikasi Ilmiah Geomatika di Kampus-kampus

Balai Penelitian Geomatika
Badan Koordinasi Survei dan Pemetaan Nasional

Bekerjasama

Jurusan Teknologi Pertanian
Fakultas Pertanian
Universitas Hasanuddin

Makassar
2009

Latar Belakang

Balai Penelitian Geomatika adalah unit riset di Bakosurtanal, yang selain melakukan aktivitas riset di bidang geomatika, juga memiliki tugas untuk mendiseminasikan hasil-hasil riset. Aktivitas diseminasi ini dilakukan dalam berbagai bentuk, salah satunya adalah seminar atau forum komunikasi untuk umum.

Hingga tahun 2007, acara seminar ini hampir selalu dilakukan terpusat di kantor Bakosurtanal di Cibinong atau di sebuah hotel atau convention center di Jakarta. Namun setelah dilakukan evaluasi, tampak bahwa seminar yang dilakukan terpusat ini kurang efektif dari sisi target audience, serta juga relatif mahal. Oleh karena itu, mulai tahun 2008 dicoba bentuk lain yang disebut “GeoCampus”. read more

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