Creating a 3D map of the world’s largest volcanic cave to aid future space missions

尽管兰萨罗特岛和月球相距数十万公里，但具有出色的相似之处。西班牙岛属于大西洋的金丝雀群岛，是世界上最大的火山洞穴和类似于月球景观的风景。实际上，在太空任务之前，该岛被选为宇航员训练的地点。最近，Lanzarote的Corona Lava Tube帮助了欧洲航天局的团队探索和研究在月球和火星等行星上观察到的类似特征的洞穴。

As a result of the latest advancements and innovation in geospatial technology, several field surveys were conducted in 2017 led by Tommaso Santagata from the Virtual Geographic AgencyVigea，，，，deploying3D Terrestrial Laser Scanning(TLS) and移动映射解决方案，，，，resulting in the first ever 3D replica of the largest lava tube on Earth.

探索电晕熔岩管的深度

Located in the north of Lanzarote, the Corona lava tube extends over 8.5 kilometres and is made up of both dry and submerged passages, with some sections more than 25 metres wide. Although the first explorations and initial mapping began in the seventies, its real extension was practically unknown until the early sixties when the first topographic survey was carried out. This latest and most ambitious 3D scanning project, commissioned by the local government, Cabildo de Lanzarote, also implemented the latest mobile mapping technology, which is part of the European Space Agency’s training course PANGAEA-X. This training allows them to test new instruments and technologies that will be used in future space missions.

为了成功执行该项目，在一年的过程中完成了各种现场调查Leica HDS7000，，，，Leica ScanStation P40andLeica BLK360laser scanners, as well as theLeica Pegasus：背包mobile mapping solution. The result is the largest 3D replica of a lava tube on the planet with 5.7 kilometers of cave passages mapped.

Capturing every detail with the latest laser scanning technology

完成了三个单独的调查和超过440次扫描，以绘制熔岩管系统，该系统由不同的部分组成，这些部分通过外部倒塌相互连接。这些崩溃用于地理参考，在外表面的洞穴内进行的激光扫描调查。通过来自西班牙地质服务的全球导航卫星系统（GNSS）测量，光检测和射程（LIDAR）数据，通过无人驾驶飞机（UAV）飞行沿洞穴路径获得的摄影测量数据，这是可能的。

More specifically, 800 metres of the above sea level passages were mapped using the HDS7000 and an estimated five kilometres using a ScanStation P40. In addition, the BLK360 imaging laser scanner was deployed to scan an upper level of around 300 metres during the PANGAEA-X expedition.

Increased accuracy and mobility with the Leica Pegasus:Backpack

To generate an even more detailed 3D map, a survey was performed using the Pegasus:Backpack mobile mapping solution. Designed to capture 3D data in overground and underground environments, with images and point clouds collected by five cameras and two LiDAR profilers. Its lightweight and ergonomic structure allowed teams to comfortably navigate the difficult terrain and to instantly visualise the data on a handheld tablet computer.

“由于熔岩管系统的复杂和地下性质，Pegasus：背包被部署以获取融合的SLAM数据 - 在带有GNSS数据的户外环境中开始和结束，但在很大程度上探索了没有卫星的洞穴，”Co-Founder of Virtual Geographic Agency Vigea 3D and an expert on Lanzarote’s volcanic cave system. As the lengthiest part of the mission was carried out without any GNSS information, the second phase of the data processing was to reinforce the calculation of the path recorded using a SLAM algorithm and the information obtained by the LiDAR mounted on the Pegasus:Backpack.

处理数据并创建最终的3D地图

“收集了大量数据 - 仅与原始激光扫描数据相对应的400 GB -狮子旋风3D point cloud processing office software was then deployed to align the scans and process a unified point cloud of the cave,” says Santagata. “Once the 3D map was available in a single point cloud, several outputs were generated as topographic maps with plans and sections of the lava tube.” In addition, the data was subsequently used to produce comparisons with other lava tubes on earth, with the objective of studying similar features on the Moon and Mars — this operation was performed using theAutodesk AutoCAD2017 software.

Aside from its scientific purposes and training for future space missions, the data was also used to produce multimedia and interactive contents like video animations, virtual reality and desktop applications showing the wider public the lesser known parts of the Corona lava tube system. Only limited sections are open to the public at Cueva de Los Verdes and Jameos del Agua. Furthermore, the results of this project were presented during an event on the management of touristic caves organised by the Cabildo de Lanzarote in 2019, where a virtual reality stand was installed to show the cave to the public.

最新探险更新：支持搜索“进食”细菌

2021年春季，桑塔加塔（Santagata）返回兰萨罗特（Lanzarote），以支持微生物学研究项目。由塞维利亚自然资源与农业生物学研究所（CSIC）的地球生物学家安娜·米勒（Ana Miller）领导的Tubolan项目是为研究生活在Lanzarote Lava Tube Tube Systems中的微生物的。该团队的发现将有助于那些在月球和火星上寻找生活的人，这些人也有熔岩系统。尽管这些条件与地球上的条件不同，但理论上也可以支持火星和月球洞穴系统，也可以支持通过使用和转化矿物质生存和生长的化学自由营养微生物。在Tubolan项目的框架中，Santagata使用Leica BLK360进行扫描和360度视频 - 促进了研究洞穴的形成，并发现了比以往任何时候都更多的洞穴地理。可以观看令人惊叹的视频镜头维亚的YouTube频道。

进一步阅读：
SAURO F., POZZOBON R., SANTAGATA T., TOMASI I., TONELLO M., MARTÍNEZ-FRÍAS J., SMETS L.M., GÓMEZ G.D., MASSIRONI M. (2019)Volcanic Caves of Lanzarote: A Natural Laboratory for Understanding Volcano-Speleogenetic Processes and Planetary Caves.In Lanzarote and Chinijo Islands Geopark: From Earth to Space (pp. 125-142). Springer, Cham.

Sauro F.，Pozzobon R.，Massironi M.，de Bernardinis P.，Santagata T.，de Waele J.（2020）Lava tubes on Earth, Moon and Mars: a review on their size and morphology revealed by comparative planetology。地球科学评论103288。