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数字高程模型(DEM)是地理信息系统的基础数据,在与地形相关的各个领域都有非常广阔的应用前景,因此,对DEM的生产和应用研究意义重大。5.12汶川特大地震导致灾区地形严重破坏,原有的地形图及DEM数据不再具备时效性;而有效的DEM数据在当时抗震救灾和灾后重建高精度正射遥感影像地图制作、三维漫游、公路交通及地质灾害信息提取和预警预报等方面又极为重要。因此,采用何种技术方法快速获取灾区震后DEM数据是当时亟待解决的问题。利用ENVI平台,以四川省平武县为实验区,选用IRS-P5卫星遥感立体像对,尝试在不能采集到高精度地面控制点的条件下,为应急快速获取研究区震后1∶5万DEM数据的工作流程。实验结果及其精度评价表明,获取的实验区震后DEM精度达到了1∶5万或更高比例尺DEM精度标准。该研究方法及提取DEM的工作流程对类似地区应急条件下提取达到一定精度要求的DEM有实用参考价值。
Digital elevation model (DEM) is the basic data of geographic information system. It has very broad application prospect in all fields related to the terrain. Therefore, it is of great significance to the research of DEM production and application. 5.12 Wenchuan earthquake caused serious damage to the terrain in the disaster area, the original topographic maps and DEM data no longer have the timeliness; and effective DEM data at the time of earthquake relief and post-disaster reconstruction of high-precision orthophotos map production, three-dimensional roaming, road traffic And geological disaster information extraction and early warning and forecasting is extremely important. Therefore, what kind of technical methods are used to quickly obtain post-earthquake DEM data is a problem to be solved urgently. Using ENVI platform, taking Pingwu County in Sichuan Province as an experimental area, the IRS-P5 satellite remote sensing stereo pair was selected to try to get 1:50 000 in the study area rapidly after the earthquake was not able to acquire high-precision ground control points DEM data workflow. The experimental results and the accuracy evaluation show that the acquired DEM accuracy of the experimental area reaches 1: 50000 or higher DEM accuracy standard. The research method and workflow for extracting DEM have practical reference values for DEMs with certain accuracy requirements under emergency conditions in similar areas.