小班不等概抽样辅助因子的选择与分析

Selection and analysis of auxiliary factors using sampling method of sub-compartment

采用广东省博罗县2005年小班二类调查数据,以及2005年该区的Landsat ETM+遥感影像数据,按树种、龄组、树种与龄组组合进行小班类型划分,并在此基础上对小班面积、小班面积×郁闭度、小班面积×小班平均归一化植被指数(NDVI)等辅助因子与小班蓄积量的相关性进行了分析。结果表明:(1)采用小班面积×小班郁闭度(即小班树冠投影和)作为不等概抽样(PPS)辅助因子与小班蓄积相关性最好;(2)按龄组与树种组合分类型优于只按龄组或只按树种分类型后辅助因子与小班蓄积的相关性;而只按龄组分类型又优于只按树种分类型后辅助因子与小班蓄积的相关性;(3)小班平均NDVI值×小班面积(即小班像元NDVI值和)与小班蓄积量具有较好的相关性,可以作为小班不等概抽样的辅助因子,而且较小班面积与小班郁闭度之积有更好的现势性和可行性。

According to the species, age class and their combinations, the sub-compartment was carried out using the data of forest inventory for management plan and ETM data in Boluo county of Guangdong province. In this paper, the correlativity between the volume of sub-compartment and auxiliary factors, i. e. , sub-compartment area, the product of sub-compartment area and canopy closure, and the product＇of sub-compartment area and its NDVI, was analyzed. The results showed that they all had good correlativity. Among them, the product of sub-compartment area and average of NDVI had the best. The NDVI value of sub-compartment pixel could be selected as the auxiliary factor of sampling probability proportional to size （PPS）. This method could be used as data smoothing treatment in sampling of sub- compartment to raise estimation accuracy.