SGER: An Investigation of Landslide Assessment and Delineation Using Airborne Laser Swath Mapping

山体滑坡会造成广泛的破坏；因此，及早发现、监测和评估潜在问题领域至关重要。识别即将发生的滑坡位置的能力将有助于缓解，从而减少重大滑坡的发展、服务中断和可能的生命损失。确定滑坡易发地区特征的第一步是对其表面进行等高线测绘。然而，由于地形的变化，标准测量技术很少提供小于3米（10英尺）的等高线间隔。不幸的是，这一决议不适合描绘未来滑坡的发展和补救措施。然而，最近在微型计算机、激光和GPS定位技术方面的进步，已经导致了一种紧凑、轻便的机载激光测绘系统的发展，这种系统可以从一架小型飞机上操作。它可以让一个人在一小时内绘制100平方公里的地图，并最终创建一个由间隔1米的数据点组成的三维表面地图。此外数据采集速度快，垂直精度可达5 ~ 10厘米。（2到4英寸）通常是可能的。在飞行过程中，激光发出的脉冲击中地面并被反射回飞机。通过测量脉冲完成往返所需的时间（每秒10,000次）来确定每个点离飞机的距离。然后，通过知道飞机的位置和高度，就可以计算出地面的绝对高度和坐标。飞机上和地面（地勤人员）上的几个GPS系统随时提供飞机位置的精确位置信息。本研究的目的是评估机载激光测绘（ALSM）识别和绘制滑坡区域的精度和能力。南达科他州密苏里河流域的选定地区将被用作测试地点。将执行一系列测量和绘图策略，以确定最有效、最敏感和最具成本效益的方法来评估和监测滑坡地区。一旦完成这项工作，就将对数据进行评估，以建立描述滑坡特征所必需的相关参数。

Landslides can cause extensive damage; hence early detection, monitoring and assessment of potential problem areas are critically important. The ability to recognize impending slide locations would assist mitigation, thereby reducing major landslide development, disruption of services and possible loss of life. The first step in the characterization of a landslide prone area is the contour mapping of its surface. However, due to the varied topography, standard surveying techniques rarely provide contour intervals smaller than 3 m (10 ft). Unfortunately, this resolution is unsuitable for delineation of future landslide development and remedial measures. However, recent advances in microcomputers, lasers and GPS positioning technology, have resulted in the development of a compact, lightweight, airborne laser mapping system that can be operated from a small airplane. It allows one to map 100 square kilometers in a single hour, and ultimately create a three-dimensional surface map made up of data points spaced 1-meter apart. In addition to rapid data collection, vertical accuracies of 5 to 10 cm. (2 to 4 inches) are usually possible. During a flight, the laser sends out pulses that hit the ground surface and are reflected back to the plane. By measuring the time it takes the pulses (10,000 per second) to complete the roundtrip determines how far away each point is from the aircraft. Then, by knowing where and how high the aircraft is, allows one to compute the absolute height and coordinates of the ground surface. Several GPS systems both in the aircraft and on the ground (ground crews) provide precise location information of the aircraft's position at all times. The goal of this research is to assess the accuracy and capability of airborne laser swath mapping (ALSM) to identify and map landslide areas. Selected areas in South Dakota's Missouri River valley will be used as test sites. A series of measurement and mapping strategies will be performed to determine the most efficient, highest sensitivity, and cost effective approach to assess and monitor landslide areas. Once this is accomplished, an evaluation of the data will then be performed to establish those pertinent parameters necessary to characterize landslides.