Creating an interactive 3D model of a cave in a world-famous glacier

Author:Tommaso Santagata，，，，Farouk Kadded

阿根廷的Perito Moreno冰川是世界上最重要的自然旅游景点之一。自19世纪以来，探险家和地质学家对其表面进行了研究，但是冰川中的腔体太危险了，无法步行探索。2017年，由意大利La Venta Esplorazioni Geografiche和法国Spélé'IceAssociations组织的一项研究项目旨在研究使用地面激光扫描（TLS）和无人驾驶汽车（无人驾驶汽车）的冰川边缘的入口。该项目的目的之一是记录将来可以使用的信息，以研究冰川冰融化的速度。收集到的三维扫描数据后来被用于创建一个交互式3D地图，该团队已公开可用。

Getting closer to the Perito Moreno glacier using 3D mapping

这Perito Moreno Glacier is located in Los Glaciares National Park in the Southern Patagonian Ice Field, the largest temperate ice mass in the Southern Hemisphere. It has an area of more than 250km² and extends 30 km from the Lago Argentino East towards the border with Chile West. Its relatively stable condition has made it one of the most famous tourist attractions in Argentina, drawing nearly one hundred thousand visitors each year.

关于冰川的洞穴知之甚少，因为它们太危险了，无法探索。从洞穴天花板上有很大一块冰块的不断掉落。作为Magpat项目的一部分（巴塔哥尼亚的微生物和冰川），La Venta Esplorazioni Geografiche和法国人Spélé’Iceorganised one of the first cave surveys of the area 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 solutionwas used to realise a 3D map of the first tens of metres inside the cave and the cave entrance.

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 tablet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解释了这一过程：“进行了大约八次激光扫描以获取必要的数据。这些操作花费了大约两个小时，并在午后实现了，以使该地区没有直接被阳光照亮。用6mm和3mm的分辨率生产激光扫描（代表了与激光扫描仪10m测得的每个点的距离），并使用仪器的内部相机获取照片。”此外，无人机从30至70m的高度飞行，进行了摄影测量飞行。

这Leica GS16- 用于摄影测量的地面控制点的自我学习GNSS智能天线 - 用于获取测量值，并测量沿冰川南北条带的速度和高程变化。它还与CS35平板电脑配对，以便可以直接在现场处理数据。

Visualising the 3D data using Leica Cyclone

这survey team usedLeica Cyclone3D point cloud processing software to align the point clouds and create a 3D model. The model was then processed further withLeica Cyclone 3DR创建项目可交付成果。Cyclone 3DR处理大多数行业标准的格式，因此团队能够将激光扫描数据与无人机拍摄的图像合并，以创建所需的模型。为了与团队以外的同事分享3D数据，Santagata使用了Leica Geosystems的免费JetStream 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 thePerito Moreno冰川中的接触洞穴的3D模型。
观看一些亮点冰川探险。

组织参与项目:《杯子ciares National Park, La Venta, Spélé’Ice, University of Milan-Bicocca, the Natural History Museum of Paris, Paris Diderot University, University of Florence, University of Bologna and Vigea – Virtual Geographic Agency.

激光扫描和GNSS调查是与法国Leica Geosystems的Farouk Kadded和Spélé’Ice Association合作进行的。