A Study on Uncovered Slope Terrain Change Using Zenith and Normal Variation Measurement Technique

本研究利用地面光達非接觸式掃描以取得地表高密度與精度三維坐標值之特性，來擷取裸露坡地之地形資料，提出最接近真實裸露坡地之「最或是地形」的概念，並建立地面光達掃描距離、掃描密度與地形誤差之間的函數關係，擬定地面光達獲取自訂地形圖比例尺精度條件之外業作業模式，製作符合自訂地形精度之「最或是地形」資料。研究顯示傳統測量在裸露崩塌地所得到之裸露坡地地形資料之精度與真實地形之相似度約僅66.5％，不適合作為全面性地形變化偵測之用；而本研究由地面光達所測得之「最或是地形」資料，因精度與密度都高，適合作為裸露坡地地形變化分析之資料來源。經由試驗所獲得之作業模式應用於野外測試，發現不同掃描測站位置對於比對分析結果影響甚大，且掃描距離及掃描密度的規範亦會影響比對分析之結果。本研究歸納出以固定站掃描作業為原則之裸露坡地地形變化偵測的作業規範，可提供應用地面光達為工具之地形變化監控有效的作業模式。 本研究依據地面光達取得地形點雲資料高密度之點與點間的空間關係，建立「天頂變異量測法」與「法線變異量測法」比對分析之模式。經以同一裸露土體進行降雨實驗，以三維雷射掃描技術取得降雨前後裸露土壤表面三維之點雲資料，再以上述兩種比對分析模式進行地形變化偵測。證實其中「天頂變異量測法」於偵測土體在降雨前後之地形天頂方向之變異量與土方計算模式之地形高程變化量之方向相同，可精確計算出土表淘刷與堆積處之位置、範圍及土方量變化，但對降雨前後之地形變化分析，因其不符地形單元坡面不同方向的原則，而有高估的現象；而「法線變異量測法」係針對地形單元各自法線方向變異量偵測所發展的分析模式，研究顯示對於降雨前後地形變化之偵測結果較為合理，但對其土方量之估算則尚難有效獲得。「天頂變異量測法」適合於地形產生大規模變化實際計算相關土方變化之相關量化資訊，對於平日未有外力干擾之地形變化偵測仍以「法線變異量測法」較為適合。但若將兩種方法整合成「天頂及法線變異量測法」，則可使彼此之適用性充分發揮而減少其缺點。對於一個被判定為敏感之裸露坡地，可先採「法線變異量測法」紀錄地形之變化，若遇發生災害而使地形產生變化，則可應用「天頂變異量測法」進行災害前後之地形變化量測，待裸露坡地趨於穩定之後，再又使用「法線變異量測法」紀錄與分析其後續的地形變化，即可對裸露坡地之地形變化做完整的監控與紀錄。This research got terrain information by scanning surface of uncovered slope to get high density and precision 3-D coordinates with Ground Lidar without contacting and addressed a new idea "the most probable terrain" by surveying the closest real terrain and established a function relationship of scanning distance, density and terrain error for building Ground Lidar field work procedure for a decided terrain scale precision and finished a self-making “the most probable terrain” information with the decided terrain precision. It showed that the result of traditional surveying on uncovered slope terrain was about 66.5％ similar to the real terrain and it is not suitable for detecting the terrain change. On contrarily, "the most probable terrain", with a character of high precision and density which derived by scanning with Ground Lidar of this research, It is suitable to afford for analyzing the terrain change. By using the operation model that was derived from the indoor experiment to test it on field, it was found that the position of Scanning site affected the contrast analysis result seriously and so did the criteria of scanning range and density. Therefore, the criteria of terrain change detection for uncovered slope land that was derived by this research for fixed scanning site can be used availably for a model to detect the terrain change with Ground Lidar. According to the relationship between points that was derived from the terrain point cloud data by using the Ground Lidar scanned data for analysis, this research erected a contrast and analysis model with "Zenith Variation Measurement Method" and "Normal Variation Measurement Method". With 3D cloud points of soil surface got by scanning with 3D Ground Lidar to a same soil model after precipitating experiment and then detected the terrain change of soil surface with the two above analysis methods. It was proved that the variation of zenith direction by "Zenith Variation Measurement Method" was the same with altitude variation direction of earthworks estimation, so it could be used to calculate the variation of the position of erosion and deposition, range and earthwork precisely. But the estimated result was larger than the terrain change before and after precipitating experiment for being not correspondent with the principle of different aspect for the terrain unit slope. On the other hands, "Normal Variation Measurement Method" was developed for detecting normal direction variation of each terrain unit so it is reasonable for detecting terrain change but can not calculate earthwork change availably up right now. Summary, "Normal Variation Measurement Method" was suitable to extensive terrain change for calculating earthworks change and "Normal Variation Measurement Method" was suitable to detecting terrain change with no broken by external natural force. If the two methods of the research are integrated to be "Zenith and Normal Variation Measurement method", the integrate model should be more available and can reduce its weak points. When an uncovered slope land is interpreted as to be sensitive, we can use "Normal variation measurement" firstly to record its terrain change and when larger terrain change occur by extra natural force, we can use "Zenith Variation Measurement Method" to measure the terrain change. After the terrain becomes to be stable, we can then use "Normal Variation Measurement Method" again to do the follow-up terrain change record and analysis. So, we can make an effective monitoring and recording for an uncovered slope land.摘要……………………………………………………………………………i ABSTRACT…………………………………………………………………ii 目次……………………………………………………………………………iv 表目次…………………………………………………………………………vii 圖目次…………………………………………………………………………viii 第一章 緒論……………………………………………………………………1 1-1 前言……………………………………………………………………1 1-2 研究動機與目的………………………………………………………4 1-3 研究方法………………………………………………………………5 1-4 內容編排及研究流程…………………………………………………7 第二章 文獻與相關研究之回顧………………………………………………9 2-1 邊坡破壞前的監控……………………………………………………9 2-1-1 坐標變化量測……………………………………………………9 2-1-2 物理特性量測……………………………………………………10 2-2 邊坡破壞後地形變化之監控…………………………………………11 2-2-1 數值地形測繪法…………………………………………………11 2-2-2 解析航空攝影測繪法……………………………………………12 2-2-3 地形圖資之精度偵測……………………………………………13 2-2-4 邊坡破壞前後土方量變化之估算………………………………13 2-2-4-1 網格柱估算法………………………………………………14 2-2-4-2 不規則三角柱估算法………………………………………15 2-3 光達資料取得地形現況………………………………………………16 2-4 地面光達原理與相關之應用理論……………………………………17 2-4-1 地面光達技術介紹……………………………………………17 2-4-2 地面光達之主要構造…………………………………………18 2-4-3 地面光達之測距原理……………………………………………19 2-4-4 地面光達之定位原理……………………………………………20 2-5 地面光達外業作業……………………………………………………24 2-6 地面光達內業資料處理………………………………………………26 2-7 地面光達之系統誤差…………………………………………………30 2-8 誤差傳播定律…………………………………………………………33 2-9 掃描之點雲誤差推算…………………………………………………35 2-10 土方量誤差推演……………………………………………………37 2-11 本研究所使用之地面光達設備介紹…………………………………38 第三章 理論推導與模式建立…………………………………………………40 3-1 裸露坡地最或是地形之定義…………………………………………40 3-1-1 標準化之裸露坡地「最或是地形」………………………………41 3-1-2 符合驗收之裸露坡地「最或是地形」……………………………42 3-1-3 裸露坡地「最或是」坡面坐標點之密度…………………………42 3-1-4 地面光達法與傳統測量法所測得裸露坡地地形之差異………44 3-2 影響裸露坡地「最或是地形」資料精度之因素………………………50 3-2-1 掃描測站至掃描物體距離對裸露坡地地形資料精度之影響…50 3-2-2 掃描解析度（密度）對裸露坡地地形資料精度之影響…………52 3-3 天頂及法線變異量測法分析模式……………………………………55 3-3-1 裸露坡地地形變化偵測之資料來源……………………………55 3-3-2 裸露坡地地形變化偵測模式之建立……………………………56 3-3-3 天頂變異量測法…………………………………………………57 3-3-4 法線變異量測法…………………………………………………62 3-4 比對分析後之平均地形誤差…………………………………………66 第四章 模式分析之結果與討論………………………………………………67 4-1 室內試驗部份－降雨實驗前後土體地形變化偵測…………………67 4-1-1 試驗設計…………………………………………………………67 4-1-2 降雨實驗前後土體之整體土方量變化…………………………73 4-1-3 天頂變異量測法進行地形變化分析……………………………73 4-1-4 法線變異量測法進行地形變化分析……………………………79 4-1-5 討論………………………………………………………………82 4-2 野外實際範例分析－雲林縣斗六湖本村裸露坡地地形變化偵測…83 4-2-1 野外範例地形變化分析資料蒐集執行…………………………83 4-2-2 裸露地地形變化偵測……………………………………………94 4-2-3 討論……………………………………………………………101 4-2-3-1 不同掃描測站對比對分析成果之影響…………………101 4-2-3-2不同掃描密度對比對分析成果之影響……………………112 4-2-3-3 環境因素所導致之系統誤差……………………………113 4-2-4小結……………………………………………………………113 4-3 地面光達進行裸露坡地地形變化分析之作業規範………………114 4-3-1 外業之作業規範………………………………………………114 4-3-2 內業之作業規範………………………………………………118 第五章 結論與建議…………………………………………………………119 參考文獻………………………………………………………………………12

惠蓀林場紅檜人工林與闊葉樹次生林生態系經營模式之導入

The goal of forest managements has transformed since the 1960s from timber production to multi-purpose utilization, and culminated in the adoption of ecosystem management USDA Forestry Service in 1992, which emphasizes the maintenance of diversity and int林業經營目標從早期的傳統木材生產，擴展至1960年代的多目標經營，而於1992年美國農部林務署更發展出生態系經營的理念，強調森林生態系的多樣性與完整性。本研究選定國立中興大學惠蓀林場中二個林班內之紅繪造林地為試區，探討如何將生態系經營之理念落實於試區內，且於248號造林地降近之闊葉樹次生林，設置二個調查樣區作為試驗研究的對照組。試區中之紅檜多為分叉叢生，且多入侵的闊葉樹幼木，故進行疏伐處理，希藉以提高其生產力與歧異度，疏伐度的決定係以胸高斷面積為其介量，訂有30、50、60%等三種疏伐度，疏伐後若有較大