单 位：
北京林业大学;安徽农业大学理学院北京林业大学测绘与3S技术研究中心华北水利水电学院资源与环境学院哈尔滨师范大学地理科学学院
关键词：
电子角规;普通角规;同心圆技术;森林蓄积;PDA
摘 要：
为了实现森林蓄积的精准和实时测定,该文以北京市鹫峰林场部分样地为例,提出电子角规多重同心圆法测定森林蓄积的原理和方法。研究表明,基于电子角规5重同心圆法所测样地的单位面积的森林蓄积值逐渐变小,到第4个同心圆后,森林蓄积值变化趋于稳定,蓄积测定结果可靠。采用普通角规多个观测点测定的森林蓄积分布相对没有规律,变化趋势不明显,尽管角规计数变化率小,但蓄积变化值相对较大。对林相不一致、空间分布不均匀的样地,其森林蓄积观测值精度较低,利用普通角规多点测定森林蓄积的相对误差达40%。电子角规采用望远镜和CCD系统,大大减小了错读和误读的概率,同时,利用PDA配合相应的软件自动计算,实现森林蓄积测定的自动化和精准化。
译 名：
Technology of multiple concentric circles for surveying forest volume with electronic angle gauge
作 者：
Dong Bin 1,2,Yang Xiaoming 3,Feng Zhongke 2,Tang Xuehai 2,Zhang Dongyou 2,4,Du Lingfang 2(1.School of Science,Anhui Agricultural University,Hefei 230036,China;2.Institute of GIS,RS&GPS,Beijing Forestry University,Beijing 100083,China;3.School of Resources and Environment,North China University of Water Conservancy and Electric Power,Zhengzhou 450011,China;4.School of Geography Science,Harbin Normal University,Haerbin 150080,China)
关键词：
electronic angle gauge,conventional angle gage,concentric circles technology,forest volume,PDA
摘 要：
In order to realize the precision and real-time measurement of the forest volume,the paper took the partial plots of the Jiufeng Forest Farm as the case to propose the principle and method of the forest volume measurement by the multiple concentric circles with the electronic angle gauge.The study showed that the forest volume of the spots measured by five concentric circles with the electronic angle gauge decreased gradually.The change tended to be stable when reaching the fourth concentric circle,with reliable results.On the contrary,there was no regularity in measurement by using the multiple observation points based on the conventional angle gauge,with insignificant changing trend.There was low changing rate of the angle gauge calculation,but the volume changing was relatively large.As for the spots with inconsistent forest forms and uneven spatial distribution,the forest volume was with the low precision.The relative errors of the forest volume by using the multiple observation points based on the conventional angle gauge could reach 40%.The electronic angle gauge took the telescope and charge-coupled device(CCD)system,which largely reduced the probability of the misreading.Meanwhile,the automatic calculation was made by PDA to realize the automation and precision of the forest volume measurement.
