Potential of the kNN method for estimation and monitoring off-reserve forest resources in Ghana [Elektronische Ressource] / by Christian Kutzer

Kutzer

Informations

• Publié par: albert-ludwigs-universitat_freiburg
• Publié le: 01 janvier 2008
• Nombre de lectures: 53
• Langue: English
• Poids de l'ouvrage: 4 Mo

Extrait

Potential of the kNN Method for Estimation and Monitoring
off-Reserve Forest Resources in Ghana





Thesis submitted in partial fulfilment of the requirements of
the degree Doctor rer. nat. of the
Faculty of Forest and Environmental Sciences,
Albert-Ludwigs-Universität
Freiburg im Breisgau, Germany


by


Christian Kutzer





Freiburg im Breisgau, Germany
2008













































Name of Dean: Prof. Dr. Heinz Rennenberg
Name of Supervisor: Prof. Dr. Dr. h. c. Dieter R. Pelz
Name of 2nd Reviewer: Prof. Dr. Barbara Koch
Date of thesis defence: 23rd June 2008

Acknowledgements
First I would like to thank my supervisor Prof. Dr. Dr. h. c. Dieter R. Pelz, director of
the Department of Forest Biometry, for accepting me as his student, for his patience,
and invaluable advice to complete this study. I am grateful to Tropenbos International
for cooperating and supporting fieldwork and data acquisition. I also thank Prof. Dr.
Barbara Koch, director of the Department of Remote Sensing and Landscape
Information Systems, for taking up the role of co-referent of this study.
I am very much indebted to Dr. Francis Bih and his family, with whom I worked and
lived during my stay in Ghana. For his extraordinary efforts during fieldwork, I thank
Kwame Dankwa. Mr S. K. Nketiah and the entire staff of Tropenbos International-
Ghana deserve my thanks for their warm reception, support and hospitality.
I would like to thank Dr. Patricia Clesly for proofreading my English. Thanks also go
to Dr. Roberto Scoz, Dr. Lilian Soto, Dr. Weeraphart Khunrattanasiri, and to all my
colleagues in the Department of Forest Biometry and the Department of Remote
Sensing and Landscape Information Systems, who have contributed to the success
of my work.
Finally I would like to thank Dr. Wolfgang Stümer, who developed and provided the
kNN programme for the calculations of this study.



i
Table of Contents
List of Figures.................................................................................................iv
List of Tables ..................................................................................................viii
List of Acronyms ............................................................................................x
Abstract...........................................................................................................xii
1 Introduction ............................................................................................1
1.1 Background.........................................................................2
1.2 Objectives ...........................................................................3
1.3 Framework of the study.......................................................4
2 State of the Art .......................................................................................6
2.1 Remote Sensing and Survey Instruments...........................6
2.2.1 History of the kNN Method..................................................14
2.2.2 Applications of the kNN Method in Forestry........................17
3 The Study Area.......................................................................................19
3.1 Geography, Topography, Climate .......................................19
3.2 Soil and Vegetation.............................................................20
3.3 Land Use.............................................................................21
3.3.1 Annual Cropping System ....................................................22
3.3.2 Perennial Cropping System ................................................22
3.3.3 Young Fallowing System.....................................................23
3.3.4 Old Fallowing System .........................................................23
3.3.5 Grass Fallowing System .....................................................24
3.4 Land Use Types..................................................................24
3.4.1 Bamboo...............................................................................24
3.4.2 Banana/Plantain Plantation.................................................25
3.4.3 Bush Fallow ........................................................................26
3.4.4 Cocoa Plantation.................................................................27
3.4.5 Elephant Grass ...................................................................27
3.4.6 Grassy Vegetation ..............................................................28
3.4.7 Herbaceous vegetation .......................................................29
3.4.8 Oil Palm Plantation..............................................................29
3.4.9 Raphia Palm .......................................................................30
3.4.10 Trees/Forest........................................................................31 Table of Contents ii

4 Remote Sensing Data ............................................................................32
4.1 ASTER Image .....................................................................32
4.1.1 Image Geometric Correction...............................................32
4.1.1.1 Selection of Basing Points………………………………….….33
4.1.1.2 Error of the Geometric Image Correction………………….…34
4.1.2 Generation of Extra Bands..................................................36
5 Methods ..................................................................................................42
5.1 Inventory Design/Data Acquisition ......................................42
5.2 GPS Receiver Specifications and Position Accuracy..........45
5.3 kNN Method........................................................................46
5.3.1 The kNN Method for Metric Data ........................................46
5.3.2 The kNN Method for Categorical Data ................................51
5.3.3 Operation of the kNN Method .............................................51
5.4 Error Analysis......................................................................53
5.4.1 Precision .............................................................................53
5.4.2 Accuracy Assessment.........................................................54
5.4.2.1 Confusion Matrix………………………………………………..55
5.4.2.2 Kappa Coefficient……………………………….58
5.4.3 Bias.....................................................................................60
6 Analyses and Results ............................................................................61
6.1 Sample Size of the Terrestrial Plots....................................61
6.2 Analyses of Optimization Options .......................................63
6.2.1 Band Number......................................................................63
6.2.2 Band Combination ..............................................................65
6.2.3 Land Use Type vs. Band Combination................................67
6.2.4 Precision of the Classification Accuracies...........................68
6.2.5 Distribution of Sample Plots................................................72
6.2.6 Sample Size........................................................................75
6.2.7 Parameters k, r, t of the kNN Programme...........................76
6.3 Types of Classification Accuracies......................................79
6.4 Kappa Coefficient................................................................81
6.5 Classification Procedure including all Land Use Types at once
............................................................................................82
Table of Contents iii

6.6 The kNN Classification Maps..............................................85
7 Discussion and Conclusions ................................................................94
7.1 Discussion of Sample Size and Design...............................94
7.2 Band combination ...............................................................96
7.3 Accuracy, Precision and Overall Agreement.......................97
7.4 Plot Distribution...................................................................103
7.5 Sample Size of Training Pixels ...........................................105
7.6 Parameters k, r, t ................................................................106
7.7 Assessment of the Classification Results............................108
7.8 Inventory of NTFPs and Tree/Forest Resources.................109
7.9 Recommendations for the Development of a Monitoring Design
............................................................................................110
8 Summary.................................................................................................113
9 Zusammenfassung ................................................................................115
10 References.........................