Computational Virtual Measurement For Trees Dissertation Zur Erlangung des akademischen Grades doctor rerum naturalium (Dr. rer. nat.) Vorgelegt dem Rat der Chemisch-Geowissenschaftlichen Fakultät der Friedrich-Schiller-Universität Jena von MSc. Zhichao Wang geboren am 16.03.1987 in Beijing, China Gutachter: 1. 2. 3. Tag der Verteidigung: 我们的征途是星辰大海 My Conquest Is the Sea of Stars --2019, 长征五号遥三运载火箭发射 わが征くは星の大海 --1981，田中芳樹 Wir aber besitzen im Luftreich des Traums Die Herrschaft unbestritten --1844, Heinrich Heine That I lived a full life And one that was of my own choice --1813, James Elroy Flecker Contents Contents CONTENTS ......................................................................................................................................................... VII LIST OF FIGURES................................................................................................................................................. XI LIST OF TABLES ................................................................................................................................................. XV LIST OF SYMBOLS AND ABBREVIATIONS ............................................................................................... XVII ACKNOWLEDGMENTS ................................................................................................................................... XIX ABSTRACT ......................................................................................................................................................... XXI ZUSAMMENFASSUNG ................................................................................................................................. XXIII CHAPTER ONE, STUDY OBJECTIVES .......................................................................................................... 1 1.1 FOREST INVENTORY AND MODELING METHODS .......................................................................................................... 2 1.2 DEPENDENCY OF METHODS AND CHAIN OF VALIDATION ........................................................................................... 5 1.3 STUDY OBJECTIVES ......................................................................................................................................................... 6 1.4 THESIS STRUCTURE ......................................................................................................................................................... 7 CHAPTER TWO, STATE OF THE ART ............................................................................................................... 9 2.1 NATIONAL FOREST INVENTORY ................................................................................................................................... 10 2.1.1 Additional reviewing materials from websites ..................................................................................... 10 2.1.2 Scopes and working divisions of NFI ....................................................................................................... 10 2.1.3 Sample plot design and measurement ................................................................................................... 11 2.1.4 Forest thematic mapping ............................................................................................................................ 13 2.2 MEASURING FORESTS USING LIDAR .......................................................................................................................... 14 2.2.1 LiDAR sensors .................................................................................................................................................. 14 2.2.2 LiDAR data sources, classified by the visibility of tree structures .................................................. 14 2.2.3 LiDAR data processing algorithms for tree parameters ................................................................... 17 2.3 VIRTUAL GEOGRAPHIC ENVIRONMENT AND PHYSICAL SIMULATION ........................................................................ 23 2.3.1 General information ...................................................................................................................................... 23 2.3.2 Virtual geographic environment ............................................................................................................... 23 2.3.3 Physical simulation ......................................................................................................................................... 25 2.4 DRAWBACKS OF EXISTING FOREST FIELD MEASURING METHODS AND POTENTIAL DIRECTIONS FOR FUTURE IMPROVEMENTS ................................................................................................................................................................... 28 CHAPTER THREE, COMPUTATIONAL VIRTUAL MEASUREMENT .......................................................... 31 3.1 METHOD DESCRIPTION ................................................................................................................................................ 32 3.2 VIRTUAL RULER, A CONCEPTUAL IMPLEMENTATION OF CVM .................................................................................. 34 3.2.1 Aims of the conceptual implementation of virtual ruler ................................................................... 34 VII 3.2.2 The semi-empirical data processing ....................................................................................................... 34 3.2.3 Artificial stem disk, point cloud, and key points ................................................................................. 35 3.2.4 Establishing a virtual space ........................................................................................................................ 36 3.2.5 Designing a physical simulation scenario ............................................................................................. 37 3.2.6 Modeling methods, the circle fitting ....................................................................................................... 39 3.2.7 Results................................................................................................................................................................ 40 3.3 DEVELOPMENT STAGES OF TWO FORMAL IMPLEMENTATIONS................................................................................. 42 3.4 CONCLUSION OF CVM METHOD ............................................................................................................................... 43 CHAPTER FOUR, DATA COLLECTION .......................................................................................................... 45 4.1 ARTIFICIAL OBJECTS AND STEMS FOR THE VWD METHODS ..................................................................................... 46 4.1.1 General information ...................................................................................................................................... 46 4.1.2 Regular shaped objects ............................................................................................................................... 46 4.1.3 Artificial Stems ................................................................................................................................................ 48 4.2 LIDAR FIELD MEASUREMENTS FOR THE SUNLIGHT ANALYSIS METHODS................................................................. 51 4.2.1 General information and acknowledgments ........................................................................................ 51 4.2.2 LiDAR field measurement in stage one ................................................................................................. 51 4.2.3 LiDAR field measurement in stage two .................................................................................................. 52 4.3 CONCLUSION OF DATA COLLECTION ......................................................................................................................... 53 CHAPTER FIVE, METHODS ............................................................................................................................. 55 5.1 METHODS IN VIRTUAL WATER DISPLACEMENT .......................................................................................................... 56 5.1.1 General information of VWD methods .................................................................................................. 56 5.1.2 VWD Methods in stage one, displacement using massive VWMs ............................................... 56 5.1.3 VWD Methods in stage two, displacement using few VWMs ........................................................ 65 5.2 METHODS IN SUNLIGHT ANALYSIS ............................................................................................................................. 67 5.2.1 General information of sunlight analysis ............................................................................................... 67 5.2.2 Sunlight analysis methods in stage one, investigating single tree light condition ................. 67 5.2.3 Sunlight analysis methods in stage two, investigating interferences from surroundings for single tree light condition ..................................................................................................................................... 72 5.3 CONCLUSION OF METHODS .......................................................................................................................................