映射芬兰的海洋地板

作者：Penny Boviatsou

Accurate nautical charts ensure safe navigation and better voyage planning. These are graphic representations of a maritime area and coastal regions, showing depths of water and heights of land, details of the seabed and the coastline, navigational threats, and structures, such as harbours.

Nautical charts are essential tools for marine navigation,Meritaito Ltd是一家领先的芬兰海洋调查服务和基础设施管理公司，为芬兰水域安全导航生产官方航海图。该公司在全面的服务中拥有数十年的经验：

1. Maintenance of waterways
2. Use and maintenance of canals
3. 水文测量服务
4. 液压工程
5. 水道设计和制造艾滋病导航
6. Oil spill response services.

Meritaito成立于2010年，当时芬兰海事局的水道职能，芬兰铁路管理局和芬兰道路管理局合并到芬兰运输机构（FTA）中。自由贸易协定是根据运输和沟通部的权力运作的政府机构;其主要责任是政府监督运输系统的维护和发展。

Organising the mission

深度以各种方式测量。从历史上看，使用了探测线。在现代时代，回声探测和激光乐队用于测量海洋的海床。FTA在过去在芬兰进行了沐浴泳装，但成功相当差。2015年，Meritaito在FTA的要求之后组织了一项试点计划，而且这次使用新技术包括徕卡Chiroptera II., a coastal survey LiDAR sensor. The results of the pilot program were satisfactory, and FTA requested two more hydrographic surveys, these took place in 2016 and 2017.

从调查中获得的数据用于产生最新的大型航海图表。三种不同的技术用于数据采集：

1. Singlebeam echosounding (SBES)
2. 多阵线echosound（MBES）
3. Bathymetric LiDAR.

这些调查曾担任过guide for Meritaito for managing hydrographic surveys and improving the execution of a project containing bathymetric information from different data collection methods。

Gaining the knowledge

For the first survey, Meritaito used different bathymetric sensors – among them was the Chiroptera II. The LiDAR data was requested separately, and, consequently, the surveys took place in different times.

“For the shallow areas, we used single-beam echosounders and the Leica Chiroptera II, and for the deeper areas multibeam echosounders,”said Aaro Nurmiainen, Meritaito LiDAR expert.

Once completed the data evaluation, Meritaito created a report for the FTA. After the analysis of the report, FTA concluded the Chiroptera II coastal survey LiDAR technology could be used to replace the singlebeam echosounders in the coastal areas.

“LIDAR技术为其他应用开辟了途径，”said Nurmiainen.“考虑到长coastline and big number of lakes in Finland, this is浅水调查的理想工具。“

Leading with vast experience

In the second project, FTA excluded all other methods and only kept LiDAR data for the shallow water areas. Meritaito used multi beam echosounders for the deeper parts.

“Chirooptera II传感器允许快速准确的映射，更换远效率更低的单束映射工具，”解释了Nurmiainen。

Meritaito used theLeica Lidar调查工作室(Leica LSS) and Terrasolid software suite to create a fast and automated workflow. After the processing and evaluation, FTA received the final product ready for the agency’s mapping projects.

“The Chiroptera II captured the full waveform in both the 35 kHz bathymetric channel and the 500 kHz topographic channel and gave us seamless coastal and land surveying results,”解释了Nurmiainen。“The results after the data processing in the second survey were not comparable with any other method previously used.”