ABSTRACT With scant information available on domestic DEM quality and suitable evaluation methods, particularly in city regions, this study set out to evaluate and compare nine contemporary seamless DEM from different sources and spatial resolutions. The assessment focused on DEM accuracy, as well as determining the variation in data quality across several urban land cover types and slope classes. This was systematically determined against independent LiDAR-derived control points, co-registered reference grids, and resampled data from relevant land cover information. It showed that different sensor configurations and interpolation techniques directly relate to the unique ground cover and topographic variations as manifested by the particular digital surface model (DSM) or terrain model (DTM). An experimental photogrammetric DTM and SA National DEM compared very well with ‘off-the-shelf’ tri-stereo Elevation4™ and WorldDEM™ DTM products. Their good performance eluded to them being the least affected by land surface cover and gradient variations. The accuracy metrics produced by the AW3D30 DEM throughout were on average substantially higher than those calculated for both the National DEM and the SRTM-X DEM. Two local commercial versions, the older SADTM and more recent SUDEM, and lastly the ASTER GDEM2 in particular, yielded noticeably less accurate results that would restrain their usefulness.

中文翻译：

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分析具有不同高程源的不同尺度城市区域的 DEM 误差

摘要 由于国内 DEM 质量和合适的评估方法的可用信息很少，特别是在城市地区，本研究开始评估和比较来自不同来源和空间分辨率的九个当代无缝 DEM。评估的重点是 DEM 的准确性，以及确定多种城市土地覆盖类型和坡度等级的数据质量变化。这是根据独立的 LiDAR 派生控制点、共同注册的参考网格和来自相关土地覆盖信息的重新采样数据系统地确定的。它表明，不同的传感器配置和插值技术与特定的数字表面模型 (DSM) 或地形模型 (DTM) 所表现出的独特的地面覆盖和地形变化直接相关。实验性摄影测量 DTM 和 SA National DEM 与“现成的”三立体 Elevation4™ 和 WorldDEM™ DTM 产品进行了很好的比较。它们的良好性能使它们受地表覆盖和梯度变化的影响最小。AW3D30 DEM 产生的准确度指标平均大大高于为 National DEM 和 SRTM-X DEM 计算的准确度指标。两个本地商业版本，较旧的 SADTM 和较新的 SUDEM，尤其是最后的 ASTER GDEM2，产生的结果明显不太准确，这将限制它们的实用性。AW3D30 DEM 产生的准确度指标平均大大高于为 National DEM 和 SRTM-X DEM 计算的准确度指标。两个本地商业版本，较旧的 SADTM 和较新的 SUDEM，尤其是最后的 ASTER GDEM2，产生的结果明显不太准确，这将限制它们的实用性。AW3D30 DEM 产生的准确度指标平均大大高于为 National DEM 和 SRTM-X DEM 计算的准确度指标。两个本地商业版本，较旧的 SADTM 和较新的 SUDEM，尤其是最后的 ASTER GDEM2，产生的结果明显不太准确，这将限制它们的实用性。