Heard Island RADARSAT (2002) DEM

This dataset is a Digital Elevation Model (DEM) of Heard Island derived by interferometric processing from RADARSAT images acquired on 17 February 2002 and 13 March 2002. The DEM was created by a contractor for the Australian Antarctic Data Centre. The cell size is 10 metres.\r\n\r\nProcessing stages included:\r\n\r\n1 Detection of a coastline from a RADARSAT image of Heard Island acquired 24 January 2002 and rectified using ground control points provided by a second contractor.\r\n\r\n2 Generation of the interferometric SAR (InSAR) DEM using the RADARSAT images acquired on 17 February 2002 and 13 March 2002.\r\n\r\n3 Co-registration of the InSAR DEM with a DEM derived from stereoscopic RADARSAT images acquired in March and April of 1997 and described by the metadata record 'Heard Island RADARSAT (1997) DEM'.\r\n\r\n4 Merging of the InSAR DEM with the 1997 stereoscopic DEM and the coastline detected in stage 1.\r\n\r\nThe following are available for download from the Related URLs below:\r\n\r\n1 The final DEM in ArcInfo interchange or ArcInfo ascii formats.\r\n\r\n2 The rectified RADARSAT image of Heard Island acquired 24 January 2002. Rectified using ground control points and subsequently used in processing of the DEM.\r\n\r\n3 Contours generated from the DEM and the island polygon (coastline) extracted from the rectified RADARSAT image acquired 24 January 2002.\r\n\r\n4 A detailed deport describing the generation of the DEM.\r\n\r\n5 A report by\r\n\r\nDr Arko Lucieer\r\n\r\nCentre for Spatial Information Science\r\n\r\nSchool of Geography and Environmental Studies\r\n\r\nUniversity of Tasmania\r\n\r\nPrivate Bag 76\r\n\r\nHobart 7001\r\n\r\nTasmania, Australia\r\n\r\noutlining some errors and artefacts in the DEM.\r\n\r\nDr Lucieer produced this report while working for the Australian Antarctic Division.\r\n\r\nOn 3 July 2003 Henk Brolsma (Mapping Officer, Australian Antarctic Division) wrote the following email to the contractor who created the DEM. "What I'm really interested in are the 20 metre contours for the areas with high coherency. These are the areas where most of the field work takes place and where we have a need for contours with an accuracy better than 50 metres and my reason for using INSAR in the first instance. So can you send me: 1. The 20 metre contours for the areas with high coherency? 2. The zone or line where the INSAR and Stereo Imagery were integrated? This would be very useful for the metadata." He did not receive a reply to that email and that was the reason why he was reluctant to make the DEM public. Since he won't now get a reply and the DEM is probably better than the 1997 DEM, he considers the 2002 DEM should now be published.本数据集为赫德岛（Heard Island）的数字高程模型（Digital Elevation Model, DEM），由2002年2月17日与2002年3月13日获取的RADARSAT影像经干涉处理生成。该DEM由承包商为澳大利亚南极数据中心（Australian Antarctic Data Centre）制作，像元尺寸为10米。 处理流程包括： 1. 基于2002年1月24日获取的赫德岛RADARSAT影像，通过第三方承包商提供的地面控制点进行几何校正后，提取海岸线。 2. 利用2002年2月17日与2002年3月13日获取的RADARSAT影像，生成合成孔径雷达干涉（Interferometric SAR, InSAR）DEM。 3. 将该InSAR DEM与1997年3-4月获取的立体RADARSAT影像生成的DEM进行配准，该1997年DEM的元数据记录为“Heard Island RADARSAT (1997) DEM”。 4. 将该InSAR DEM与1997年立体DEM及阶段1提取的海岸线进行融合。 以下资源可通过下方相关链接下载： 1. 最终DEM数据，格式为ArcInfo交换格式或ArcInfo ASCII格式。 2. 2002年1月24日获取的赫德岛校正后RADARSAT影像，该影像经地面控制点校正，后续用于DEM生成处理。 3. 由该DEM生成的等高线，以及从2002年1月24日校正RADARSAT影像中提取的岛屿多边形（海岸线）数据。 4. 一份详细的DEM生成方法报告。 5. 一份由塔斯马尼亚大学地理与环境研究学院空间信息科学中心Arko Lucieer博士撰写的报告——该博士曾就职于澳大利亚南极署，报告中概述了该DEM存在的部分误差与伪影。 2003年7月3日，澳大利亚南极署制图员Henk Brolsma向制作该DEM的承包商发送邮件称：“我真正需要的是高相干区域的20米等高线。这些区域正是绝大多数野外作业开展的区域，我们需要精度优于50米的等高线，这也是我最初选择合成孔径雷达干涉技术的原因。请提供：1. 高相干区域的20米等高线数据；2. 合成孔径雷达干涉DEM与立体影像的融合区域或融合线。这对元数据制作将非常有帮助。”但他未收到任何回复，这也是他此前不愿公开该DEM的原因。如今他已无法获得回复，且该2002年DEM的性能大概率优于1997年DEM，因此他认为当前应当公开这份2002年DEM。