在举世闻名的冰川中创建洞穴的交互式3D模型

作者：Tommaso Santagata,Farouk Kadded

The Perito Moreno glacier in Argentina is one of the most important natural tourist attractions in the world. Its surface has been studied by explorers and geologists since the 19th century, but cavities in the glacier are too dangerous to explore on foot. In 2017 a research project organised by the Italian La Venta Esplorazioni Geografiche and the French Spélé’Ice associations set out to study the entrance to a cave at the edge of the glacier using Terrestrial Laser Scanning (TLS) and unmanned aerial vehicles (UAVs). One of the aims of the project was to record information that could be used in the future to study how fast glacial ice is melting. The three-dimensional scanning data collected was later used to create an interactive 3D map, which the team has made publicly available.

Getting closer to the Perito Moreno glacier using 3D mapping

Perito Moreno冰川位于南部半球最大的温带冰块的南部巴塔哥尼亚冰场的Los Glaciares国家公园。它的面积超过250公里，从拉哥阿根廷东部延伸到与智利西部边界30公里。它相对稳定的状况使其成为阿根廷最著名的旅游景点之一，每年吸引近十万名游客。

Little is known about the caves of the glacier because they are too dangerous to explore; there is a constant fall of large chunks of ice from the cave ceilings. As part of the MaGPat Project (Microorganisms and Glaciers in Patagonia),La Venta Esplorazioni Geografiche和法国人Spélé’Ice有组织的第一个洞穴调查的a in 2017. The main objectives for the researchers were to investigate the micro-organisms living on the glacier and to map as much of the cave as possible. The only cavity that could be studied was an interesting contact cave excavated by a stream that directly feeds the glacier. A Leica Geosystemslaser scanning solution被用来实现洞穴和洞穴入口内第一米的3D图。

Detail from a distance with the Leica ScanStation P40

3D laser scanning technology has proven transformational for geographic surveys, explains Tommaso Santagata from La Venta, “These techniques are increasingly used in geological studies, such as in caves or for the calculation of ice surfaces and changes in ice volumes. 3D laser scanning technologies can acquire millions of points represented by 3D coordinates, at very high spatial densities on complex multi-faceted surfaces within minutes. The dense point clouds contain a huge amount of data that can be used for representation and analysis.”

In the Perito Moreno study the team used aLeica Scanstation P40, which can capture high quality 3D data and High-Dynamic Range (HDR) imaging at a long range of 270 metres. The survey-grade 3D laser scanner was positioned at a safe distance to acquire data on the surface of the glacier and the cave entrance. It was controlled using aLeica CS35平板电脑计算机，团队还用来检查该数据仍在现场时进行部分处理的数据。通过这种方式，他们能够确保调查按计划进行，同时仍然能够进行更改。集成到扫描仪中的专用摄像头用于产生彩色点云，并拍摄360°全景图像。

Santagata explains the process, “About eight laser scans were performed to acquire the necessary data. These operations took about two hours and were realised in the late afternoon in order to have the area not directly illuminated by the sun. Laser scans were produced with resolutions of 6mm and 3mm (which represent the distance of each single point measured at 10m from the laser scanner) and acquiring photographs with the internal camera of the instrument.” In addition, photogrammetry flights were carried out with UAVs flying from 30 to 70m heights.

TheLeica GS16- a self-learning GNSS smart antenna - was used to acquire measurements, both for ground control points for the photogrammetry survey and to measure velocity and elevation changes along a north-south strip of the glacier. It was also paired with the CS35 tablet computer so that data could be processed directly in the field.

Visualising the 3D data using Leica Cyclone

The survey team usedLeica Cyclone3D点云处理软件可以对齐点云并创建3D模型。然后将模型进一步处理Leica Cyclone 3DRto create the project deliverables. Cyclone 3DR handles most industry-standard formats so the team was able to merge the laser scanning data with images taken by the UAV to create the model they required. To share the 3D data with colleagues outside the team, Santagata used Leica Geosystems’ freeJetStream Viewer, which lets anyone - even those without any 3D modelling experience - easily view and manipulate point clouds.

与科学界及其他地区共享信息

Santagata explains that the detailed 3D models of the glacier give researchers an accurate record from which to measure changes in the ice: “The possibility to have such technologies in the right moment and right place allowed us to use them to obtain data that can be used in the future to compare the evolution of this part of the glacier.”

旅行后，生产了来自3D模型和3D交互模型的360°照片，以向对该地区感兴趣的任何人展示结果。在2019年在意大利举行的国际杂技会上，可以使用虚拟现实眼镜观看它，现在可以在网上生活。

Explore the3D model of a contact cave in the Perito Moreno glacier.
Watch some of the highlights from the冰川探险.

参与该项目的组织：Los Glaciarres国家公园，La Venta，Spélé’ies，Milan-Bicocca大学，巴黎自然历史博物馆，巴黎狄德罗大学，佛罗伦萨大学，博洛尼亚大学，维亚纳大学和维亚维亚大学 - 虚拟地理局。

Laser scanning and GNSS surveys were carried out in collaboration with Farouk Kadded from Leica Geosystems France and member of Spélé’Ice association.