通过移动地图技术保护荷兰免受洪水的侵害

Author:Arno Kijzerwaard

59 per cent of the Netherland’s territory is vulnerable to floods and 26 per cent is below sea level. For this Western European country, preventing and protecting against sea water level rise is of vital importance – at the North Sea flood in 1953, the Netherlands testified how important strengthening costal defences is. Due to its low and flat geography, the country contains a large extension of dikes – 17,691 kilometres to be precise.

Dikes in the country are managed by waterboards. The area in the middle of the Netherlands with the Maas, Waal and Nederrijn rivers is beautiful yet vulnerable – due to climate change the sea level is rising causing rivers to flood. To ensure citizens are safe, dikes in this area are checked every two years and completely surveyed every six years to make sure they stay high and firm enough.

Kempkes Landmeten，一家专门翻译广泛的Geodesy中数据的公司，surveyed 19 kilometres of dike along the Waal river, in the area of Waterboard Rivierenland. To give an idea of scale, this is 10% of the width of the Netherlands. In the past, dikes were surveyed with traditional survey methods involving a great deal of levelling. Over time, airborne methods, such as laser scanning from a helicopter were applied. Even when surveying from the air is far more efficient than traditional surveying, several rules, accuracies and safety measures must be applied.

选择下一代移动映射

Kempkes Landmeten与Waterboard Rivierenland讨论了一种调查堤防安全性的新方法。他们建议使用下一代移动映射技术，Leica Pegasus:Two Mobile Sensor Platform, to deliver the task with the quality requested.

A traditional survey of the whole area would have taken months to complete – the first part of19-kilometre trajectory was done in two days移动映射解决方案安装在普通汽车上，从道路上扫描。使用Pegasus：两辆在不同的车辆上进行越野调查，然后在几天内扫描了整个项目。这包括双运行，处理移动映射数据并生成结果。现在，传统的测量师只需要在无法通过移动映射捕获的数据中捕获点云和“孔”。

For this project the flexibility of the Pegasus:Two was used to the max. The compact mobile mapping solution was used on a car and quad to reach off-road locations where a normal car would get stuck.

“The Leica Pegasus:Two can be mounted on a car, boat or almost any other vehicle. The system does not have to be re-calibrated when moving from vehicle and in this way we can flexibly and easily capture the reality within millimetre range,”said Rob Kempkes, owner of Kempkes Landmeten.“由于调查更快，不需要采取安全措施，因此可以节省大量费用。”

“I have worked on this project with great pleasure. Where we used to do a traditional survey, surveyors could now drive off-road with a quad instead. They, of course, loved this,”said Erwin Perik, responsible for development.“整个工作流程非常有效。我们捕获的内容立即被检查了 - 我们从未在不知道数据很好的情况下离开网站。”

From data to a Digital Terrain Model

珀加索斯:两个几百字节包含ing point cloud data and photos were acquired for this project. The data was processed with Leica Pegasus:AutoP software, checked on quality via a multi-pass. This means the trajectory is mapped twice with the Pegasus:Two mounted on a car with opposite scanner rotation. This double-run gives a check on position quality, and reduces blind spots and unwanted traffic in the data. The resulting coloured point cloud is related to 50 ground control points and natural benchmark points.

为了调整和执行质量控制数据，通过Leica Pegasus检查了绝对位置，高度，完整性，传播和着​​色的数据：查看器和Kempkes Landmeten的自制软件。独立的调查方法（例如级别和测量概况）用于双重研究质量。

The few parts that were not covered by the scan, such as the back of buildings, or objects like drains, were surveyed with traditional methods using Leica Total Stations and GNSS receivers. Metadata of objects like numbers on light poles were gathered if not visible on the photos from the Pegasus:Two.

然后，使用传统调查的后处理数据用于为客户生成最终产品 - 一个complete 3D Digital Terrain Model with GIS metadata.

除了最终的结果外，Waterboard Rivierenland现在还能够使用所有额外的收集数据，例如使用Pegasus收集的360度球体照片：两个。多亏了额外信息的惊人来源，因此无需出门。过去，测量师必须回到现场，可以在一个位置轻松生成额外的交叉轮廓。这更快，更安全，是完美的基础，可以在日常过程中更轻松，更有信息的决策。

Daring to disrupt

“Next-generation mobile-mapping suits Kempkes Landmeten. With both legs firmly in the river clay we are a forerunner in applying innovative techniques,”said Kempkes.“When we do something, it has to be current, reliable and complete.”

Using the Pegasus:Two has proven to be more flexible, safe, faster and scalable giving Kempkes Landmeten a key advantage over the competition on this and other projects. Investments in new reality capture and processing solutions, just like Leica BLK360 imaging laser scanner and Jetstream, make sharing point cloud data even more efficient.