Photogrammetric and laser altimetric reconstruction of water levels for extreme flood event analysis
Photogrammetric and laser altimetric reconstruction of water levels for extreme flood event analysis
复制标题
用于极端洪水事件分析的水位摄影测量和激光测高重建
DOI：
10.1046/j.0031-868x.2003.00022.x
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
M. Saunders
中科院分区：
文献类型：
--
作者：
S. Lane;T. James;H. Pritchard;M. Saunders
本文评估了使用数字摄影测量估算水位的可行性。极端洪水事件期间的一个常见问题是，由于仪器故障，自动水位记录仪无法记录最高水位。本文基于使用天气遥感方法获取的数据，探讨了该问题的两种可能的解决方案。第一种方法需要：（a）高分辨率高程数据（例如，以洪泛区数字高程模型的形式）； (b) 有关最大洪水范围的平面位置的信息，例如事件后航空图像上可见的碎片线（称为残骸线）。然后可以使用平面数据来分割地形数据，以便识别水位高程。第二种方法使用数字摄影测量方法，适用于没有可用地形数据但可以在事件发生后飞行的航空图像的情况。如果该图像具有正确的比例，则可以使用数字摄影测量分析来识别图像上可见的残骸线的高程。在本文中，第二个选项与第一个选项进行了比较。研究表明，基于从激光雷达数据获得的检查数据，使用 1:4500 比例图像的桌面摄影测量方法可以产生精确至 ±0·147 m 的水位估计值。考虑到激光雷达数据的不确定性，这是对所获取精度的最差估计。与第一个选项相比，基于使用洪水轮廓分割激光雷达数据，考虑到激光雷达的质量和如何分割它的不确定性，摄影测量方法被发现更可取。
This paper assesses the feasibility of estimating water levels using digital photogrammetry. A common problem during an extreme flood event is that automated water level recorders do not record the highest water levels, as a result of instrument malfunctioning. This paper explores two possible solutions to this problem based upon data acquired using synoptic remote sensing methods. The first method requires: (a) high‐resolution elevation data (for example, in the form of a digital elevation model for the floodplain); and (b) information on the planimetric position of the maximum flood extent, such as from debris lines (known as wrack lines) visible on aerial imagery flown after the event. The planimetric data can then be used to segment the topographic data in order to identify water level elevations. The second method uses a digitial photogrammetric approach and is suitable where no topographic data are available, but aerial imagery is available, flown after the event. Provided this imagery is of the right scale, digital photogrammetric analysis may be used to identify the elevations of wrack lines visible on the imagery. In this paper, the second of these options is compared with the first. The research shows that desktop photogrammetric methods, using 1:4500 scale imagery, can yield water level estimates that are precise to ±0·147 m, on the basis of check data obtained from lidar data. This is a worst possible estimate of the acquired precision given uncertainties in the lidar data. When compared with the first option, based upon segmenting lidar data using flood outlines, the photogrammetric approach was found to be preferable given both the quality of the lidar and uncertainties over how to segment it.