ABSTRACT

In this study the accuracy of ALOS Global Digital Surface Model (AW3D30) with a point spacing of approx. 30-meter mesh was examined, taking as a case study several areas of Greece with complex geomorphologic characteristics. DSMs from ALOS stereo pairs were created using classical photogrammetric techniques. These DSMs were compared with the ALOS AW3D30 and a DEM created from digitized contours. Visual and statistical comparison of the DSMs has been performed.Check Points of known elevation selected from the National Trigonometric Network have been used to estimate the accuracy of the DSMs and the results are presented herein. It has been proved that the freely available AW3D30 DSM presents two or three times lower Root Mean Square Error (RMSE) than the respective DSMs from ALOS PRISM images. In areas with low relief such as Antiparos Island in the Cyclades complex, the ALOS AW3D30 RMSE is only 2.69 m, while in Areas with high relief such as the Chania Prefecture in Western Crete the respective error rises up to 14m. In urban area such as Athens, the capital of Greece, the respective error ranges around 12m due to the complex urban environment (high buildings, narrow urban roads, moving vehicles etc.).

摘要

在这项研究中，ALOS全球数字表面模型（AW3D30）的精度约为点间距。检查了30米的网格，并以希腊几个具有复杂地貌特征的地区为例进行了研究。使用经典摄影测量技术创建了来自ALOS立体对的DSM。这些DSM与ALOS AW3D30和由数字化轮廓创建的DEM进行了比较。进行了DSM的视觉和统计比较。已使用从国家三角网选择的已知海拔的检查点来估计DSM的准确性，并在此处显示结果。事实证明，免费提供的AW3D30 DSM的均方根误差（RMSE）比ALOS PRISM图像中相应的DSM低两倍或三倍。在基克拉迪群岛中的安提帕罗斯岛等地势低的地区，ALOS AW3D30 RMSE仅为2.69 m，而在西克里特岛的干尼亚州等地势高的地区，相应的误差则上升至14m。由于复杂的城市环境（高层建筑，狭窄的城市道路，移动的车辆等），在希腊首都雅典等市区，相应的误差范围约为1200万。