汶川震后震害区DEM提取方法研究——以平武县为例

The Method of DEM Extraction after Wenchuan Earthquake in the Earthquake Disaster Area——Take Pingwu Country for Example

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。

DEM is the basis of geographic information system data,associated with the terrain in all areas has a very broad application prospects,in the production and applications of DEM,has an important significance.Wenchuan earthquake changed the existing landscape of disaster area,lead to the original DEM data and Topographic Map no longer have timeliness,the effective DEM data for earthquake relief at the time and reconstruction accuracy orthophoto imagery map production,3D roaming,road transport and geological disaster forecast and warning information extraction,etc.is extremely important.Therefore,the technical methods adopted quickly after the earthquake disaster obtain DEM data was a serious problem.In this context,this paper use ENVI platform,selected for the study area in Sichuan Province Pingwu country,select IRS-P5 stereo pair as the main source of the data,in the emergency case of cannot be collected in high-precision ground control points,try to get the study area 1∶50 000 DEM data after the earthquake quickly.Experimental results and the accuracy assessment show that,the experimental area for post-earthquake DEM accuracy,reaching 1∶50 000 scale accuracy or higher standard.This research method and process in similar regions of emergency conditions to extract up to a certain precision of the DEM has practical reference value.