항공 LiDAR 원자료 필터링 조건에 따른 산림지역 수치표고모형 정확도 평가

Abstract

With increasing interest, there have been studies on LiDAR(Light Detection AndRanging)-based DEM(Digital Elevation Model) to acquire three dimensional topographicinformation. For producing LiDAR DEM with better accuracy, Filtering process is crucial, whereonly surface reflected LiDAR points are left to construct DEM while non-surface reflectedLiDAR points need to be removed from the raw LiDAR data. In particular, the changes ofinput values for filtering algorithm-constructing parameters are supposed to produce differentproducts. Therefore, this study is aimed to contribute to better understanding the effects of thechanges of the levels of GroundFilter Algrothm’s Mean parameter(GFmn) embedded in FUSIONsoftware on the accuracy of the LiDAR DEM products, using LiDAR data collected forHwacheon, Yangju, Gyeongsan and Jangheung watershed experimental area. The effect of GFmn level changes on the products’ accuracy is estimated by measuring and comparing the residualsbetween the elevations at the same locations of a field and different GFmn level-producedLiDAR DEM sample points. In order to test whether there are any differences among the fiveGFmn levels; 1, 3, 5, 7 and 9, One-way ANOVA is conducted. In result of One-way ANOVAtest, it is found that the change in GFmn level significantly affects the accuracy (F-value:4.915, p<0.01). After finding significance of the GFmn level effect, Tukey HSD test is alsoconducted as a Post hoc test for grouping levels by the significant differences. In result, GFmnlevels are divided into two subsets (‘7, 5, 9, 3’ vs. ‘1’). From the observation of the residualsof each individual level, it is possible to say that LiDAR DEM is generated most accuratelywhen GFmn is given as 7. Through this study, the most desirable parameter value can besuggested to produce filtered LiDAR DEM data which can provide the most accurate elevationinformation.