空气扫描技术的改进提升了生产率
Leica Terrainmapper符合大面积映射的挑战。
作者：Linda Duffy
Increased demand for aerial LiDAR is being met with improved scanning features and functionality that produce denser point clouds over larger areas in less time. As an early adopter of scanning technology, Woolpert, the fastest-growing architecture, engineering and geospatial (AEG) firm in the US, has owned and operated every product in Leica Geosystems’ LiDAR series since the ALS40 was released in 2002. Woolpert purchased its first Leica TerrainMapper in early 2019 and has since acquired three more. Today, the TerrainMapper is Woolpert’s preferred technology for large area mapping and difficult terrain, including Department of Transportation (DOT) projects and federal programs such as the United States Geological Survey (USGS) 3D Elevation Program (3DEP).
彩色的3D点云图像（顶部）可以比较在Wyo的Teton County的Wind River湖附近的美国26上观看西北地区的裸地图（底部）。
Demand for elevation data
空中LIDAR数据是许多应用的宝贵信息来源，如3D城市建模，基础设施开发，沿海和自然灾害监测和环境保护。正在进行努力来建立当前的国家激光雷达数据集，并且还有许多投资激光乐队覆盖的地方和区域实体。
对密度和准确性的预期继续升起，以匹配激光雷达传感器的增强功能。在Leica TerrainMapper释放中的性能增量改进，一个线性模式传感器，允许在更高的海拔地区收集非常密集的点云，大大减少采集时间。
“With large area mapping, efficiency really pays off,” says Joseph Seppi, vice president and geospatial sector leader at Woolpert. “Our projects can exceed 30,000 square miles, even 100,000 square miles, so the ability to fly at a higher altitude at a faster speed makes TerrainMapper an extremely efficient option.”
The TerrainMapper is capable of collecting LiDAR at flying heights between 300 metres (m) and 5,500 m and delivers USGS LiDAR Quality Level 0 (QL0) data at flying heights up to 2 kilometres (km). This outstanding level of efficiency is ideal for larger regional or national mapping projects where operating costs have a major impact on the frequency of updates.
The contours of the landscape without trees blocking the view are shown in this bare-earth point cloud image looking north on U.S 26 near Brooks Lake Creek Falls in Teton County, Wyo.
会议并超过规格
每个项目都有最小的数据要求，具体取决于预期的应用程序。例如，USGS QL1数据必须至少为每平方米（PPSM）至少8点，具有不超过10.0厘米（CM）的根均线误差（RMSE）。其他标准可能包括叶子，没有雪，没有常设水，没有雨。温带气候，落叶树和雪是障碍。在热带和亚热带气候中，云雨往往是一个问题。由于许多地理区域的具有挑战性的条件，有限的飞行窗口期间有效的数据收集对于完成工作至关重要。
2019年，怀俄明州的运输部（Wydot）与Woolpert合同，沿着西北怀俄明州西北部的大陆鸿沟延伸三个滑坡地区，靠近黄石国家公园。Woolpert收集了50 ppsm的激光雷达，并使用集成的Leica RCD30航空摄像头同时收集图像的点云。最终数字地形模型（DTM）和三角形的不规则网络（TIN）模型提供了Wydot的基线，以确定地球随时间移动的幻灯片移动，体积和速率。Wydot进行了独立的检查，并在Field收集的点与120个单独的点云高度进行比较。3.6厘米的平均高度差异超过所要求的5cm垂直精度。
The TerrainMapper has also proven effective on linear utility projects and powerline rights-of-way and successfully measures sag on elevated power lines. Even while flying faster and higher than other sensors, the TerrainMapper returns the necessary point density for a variety of projects.
“在高浮雕地形中，我们通过飞行而在没有调整到许多不同的高度的情况下实现更高的效率，”Seppi表示。“对于公用事业工作，在远远高于线的高海拔地区飞行更安全，捕获更多周围地区的额外好处。”
Woolpert also flew more than 10 USGS projects in various states in 2019 with the TerrainMapper. In states like Florida and Ohio, the large volume collection at high speeds was instrumental in completing mapping projects within one flying season, despite the weather conditions.
“某些地方的天气可能具有挑战性，让我们少努力工作，因此TerrainMapper的大容量收集能力有助于我们快速完成项目并保持一致性，”Seppi继续。“此外，该传感器的点分布，图案和优异的强度返回对于许多特征提取使用非常有益。”
收购和处理集成
后处理工作流是另一个效率影响整体项目成本的区域。WOOLPERT使用LEICA HXMAP多传感器处理平台，旨在简化TerrainMapper数据的处理。HXMAP处理，校准和登记LIDAR点云，同时处理图像传感器数据和指导点云。借助HXMAP的帮助，Woolpert提供完全加工的分类点云，满足严格的项目规范，以获得精度和密度。
“HxMap allows us to be more agile and adapt on the fly to changes,” says Seppi. “We can easily shift processing around to allocate HxMap resources from other projects when we have a critical deadline. HxMap is like a black box that automatically performs its work behind the scenes.”
Designed specifically to work with TerrainMapper data, HxMap leverages the advantages of the integrated scanner/camera system to generate all airborne data products within one single interface. HxMap offers embedded aerial triangulation and a solution for large oblique imaging projects, country-wide orthophoto projects, and large or small LiDAR projects.
连续的提高
Leica Terrainmapper是高度成功的ALS80系列后的下一代激光雷达传感器。传感器系统增加了数据收集率与飞行高度，提高了飞行规划，实现了均匀的点分布。增强的生产率节省了时间和金钱，而脉搏率较高，更大的激光功率和无紧技术有助于更高的点密度。
“徕卡地铁系统传感器只是保持更好，”Seppi说。“从ALS80的性能跳到TerrainMapper是显着的。我们发现圆形扫描模式具有大量优点，如线到线校准和调整的音高。飞行更高，更快地提高了我们的效率200-400％。自1989年以来，Leica Ge亚搏彩票手机版下载osystems产品一直是我们传感器车队的骨干。“
对3D LIDAR数据的需求正在上升，这使得及时采购和处理越来越重要。TerrainMapper与HXMAP工作流程的紧密集成加快了从数据下载到产品生成的整个过程，以支持每个映射项目的更快的转变。
