空載雷射掃描資料於推估樹冠高度之應用

Estimation of Forest Canopy Height Using Airborne Lidar Data

詹進發(Jihn-Fa Jan)

《航測及遙測學刊》 10卷1期 (2005/03) Pp. 1-14

https://doi.org/10.6574/JPRS.2005.10(1).1

摘要

森林生態系經營有賴於詳實之林分結構資訊，傳統地面調查需耗費大量人力、物力、經費與時間，不易獲得迅速且正確之資訊。空載雷射掃描儀具有高密度測點與穿透樹冠間隙之特性，可迅速獲取林分之三度空間資料，適合用於林分結構相關資料之蒐集。本研究利用以Leica,ALS40掃描陽明山地區所獲取之空載雷射掃描資料，產生林分數值表面模型，進而以林分數值表面模型與數值高程模型之差推估樹冠高度模型，並與11個地面樣區實測樹高比較，以評估其準確度。結果顯示以LIDAR資料估測樹冠高度普遍有低估之現象，若能提高數值表面模型與數值地形模型之精度，應可建立較準確之樹冠高度推估模式。

關鍵字

空載雷射掃描 ； 樹冠高度 ； 數值表面模型 ； 數值高程模型

並列摘要

Forest ecosystem management depends on detailed information about forest stand structure. Traditional ground investigation requires vast amount of manpower, resources, costs, and time, hence it is not easy to promptly obtain accurate information by using ground investigation. Airborne laser scanner (LIDAR) is capable of measuring objects at very high density and penetrating gaps among tree crowns, therefore it can rapidly obtain 3D data about forest stands, and can be used for acquiring related data about forest stand structures. This study utilized an airborne laser scanner data set, acquired using Leica ALS4O scanner, of the Yangminshan National Park area to derive digital surface model for the forest canopy. Furthermore, the forest canopy height model was estimated by computing the difference between the digital surface model and a digital elevation model. The canopy height model was compared to the tree heights measured in eleven ground sample plots in order to assess its accuracy. The results indicate that the forest canopy height is generally underestimated by using the LIDAR data. More accurate forest canopy height model can be achieved, if the accuracy of the digital surface model and digital elevation model can be improved.

並列關鍵字

airborne lidar ； canopy height ； digital surface model ； digital elevation model