Mapping the rockfall source and deposit areas in the Alps

Authors:Barbara Žabota & Gregor Bilban

Rockfalls are one of the major treats to the viability and liveability in the Alps. To recognise areas that are at high risk due to rockfalls, it is important to study historical events and develop spatial models that provide accurate mapping of rockfall deposit areas. To study the rockfall it isnecessary to validate the results of modelling on the field– here is whereLeica Zeno 20 GIS CollectorandLeica GG04 Smart Antennacome in handy.

Project RockTheAlps (RTA) is an Interreg Alpine Space project which willreinforce and strengthen the implementation of rockfall risk prevention policy and mitigation strategysupport in line with a sustainable forest management approach. To achieve this objective, the first harmonised rockfall natural risk and protection forest mapping for the entire Alps will be provided. Project RTA involves 15 interdisciplinary partners from six Alpine countries: Austria, France, Germany, Italy, Slovenia, and Switzerland.

University of Ljubljana, one of the project partners from Slovenia, is responsible for developing a historical rockfall database which will serve for the testing of rockfall model developed within RTA.

As the main goal of this historical database is to get the locations for past rockfalls, researchers from the Department for Forestry and Renewable Forest Resources of the Biotechnical Faculty decided to use Zeno 20 GIS Collector togather attributes of rockfallsand GG04 Smart Antenna for collecting theiraccurate location.

Collecting rockfalls with Esri's Collector for ArcGIS & Leica Zeno 20

An example on how to correctly measure angle and azimuth for source area (standing point of measurement marked by red line) based on available information on rockfall detachment point (purple rectangle marking the actual detachment point, green rectangle marking the top-most point of rock cliff).

When gathering information about historical rockfall events, researchers from University of Ljubljanacollected data on the location of rockfall source area and rockfall deposits. The web map within the collector was, therefore, designed in a way the user collects one location of rockfall source area as a point feature and later adds multiple locations as point features of rockfall deposits in relationship class one-to-many.

As the rockfall source area is usually inaccessible, the faculty researchers designed a method to extract the location for the source area from a standing point. The exact location was later calculated based on angle and azimuth measurements using a precise digital terrain model.

除位置外，ArcGIS用户的ESRI收集器还可以添加不同的属性（例如，源区域类型或森林封面）和存款功能，例如尺寸，岩石的形状以及岩石停止的原因。如图所示，这两个功能都允许添加注释，附件和跟踪编辑器。

ArcGI的ESRI收集器可以离线使用 - 用户还原互联网连接后，收集的数据将同步到网络地图，并且可以由其他用户看到。此外，可以将不同类型的地图添加到应用程序中，并将其上传到您的设备上，以实现离线使用。

Leica Zeno 20将用于岩石映射的ArcGIS提供了ESRI收集器的精度。

Combining Esri's Collector for ArcGIS with Leica Zeno and Leica GG04 Smart Antenna

Based on measurements of angle and azimuth from different standing points (blue dots) and digital terrain model the actual location of rockfall source area (red dot) is being calculated.

The decision for top-class combination of Zeno GG04 Smart Antenna and 20 GIS Collector was no coincidence.

“在购买之前，我们在我们日常工作中面临的最苛刻的条件下测试了GG04智能天线，例如狭窄的山谷和树冠。它的GNSS测量引擎为我们提供了位置可用性和其他设备无法实现的准确性。另一方面，Zeno 20是一个坚固的基于Android的控制器，屏幕足够大，可以方便地工作，同时仍然可以舒适地舒适地安装。”said Frédéric Berger, communication manager of the RockTheAlps project.

While using Esri's Collector for ArcGIS with Zeno 20 for collaborative work of several field crews and project partners on the same database, the University of Ljubljana faculty researchers also make use of Leica Zeno Mobile software for many other mapping projects.

“我们喜欢Leica Zeno移动直观用户界面。虽然仍然包含必要的GIS功能，但其自动功能使我们能够将精度值存储为点功能的属性。所有这些都提高了我们地图的质量，”said Milan Kobal, head of the RockTheAlps project at the University of Ljubljana.

Leica Geosystems GNSS equipment offered the Slovenian team of researchers even more.“Due to the openness of Zeno GG04 we can connect this Smart Antenna to nearly any device or software requiring highest accuracy. This opens us additional options for future projects and research,”concluded Kobal.