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Posts from December 2010


EGU 2011 sessions on high-resolution topography and LiDAR

Posted on Tue, December 21, 2010 by Chris Crosby in MeetingsTLS

Now that the 2010 AGU meeting is over, it is time to start thinking about the 2011 European Geoscience Union General Assembly in Vienna, Austria, April 3-8, 2011.  The EGU abstract submission deadline is January 10th, 2011.

In addition to the Digital Landscapes: Quantitative Interrogation & Use session highlighted on the OpenTopography blog previously, there are two other sessions that appear to be directly applicable to OpenTopography users:

GM2.3 High definition topography - close range data acquisition and analysis:

Recent advances in surveying technology and better availability of high precision surveying tools made it easy for geomorphologists to benefit from data with higher spatial resolution as well as data with much better precision than just a couple years ago. In this session we want to

(i) increase the awareness of modern surveying techniques and their application to geomorphology,

(ii) provide a platform for researchers to present their experiences with laser scanners, range cameras, close range photogrammetry, terrestrial RADAR as well as other new surveying tools and

(iii) provide a platform for innovative solutions capable of generating input data for current and future models in geomorphology.

The main focus of this session will be towards the applications of close range measurements in small to medium size applications.
The proposed session has an overlap with ISPRS Commission V Working Group V/6 - “Close range morphological measurements for the earth sciences”. While the ISPRS commission meetings are typically visited by professionals of geodesy a similar session at EGU allows better communication between professional surveyors and geomorphologists.

GM2.2 Airborne and Terrestrial Laser Scanning and geomorphology: possibilities, problems, and solutions:

In the recent years laser scanning (also called LiDAR) became a very effective tool for high-resolution data acquisition of geomorphic surfaces. Airborne Laser Scanning (ALS) is a straightforward and very precise tool for creating digital surface models (DSM) up to sub-meter resolution. In order to derive Digital Terrain Models (DTMs) from DSMs at this resolution sophisticated data processing techniques are required to filter out the effects of man-made structures and the canopy cover, therefore their direct application in geomorphology often requires specific geomophological knowledge to avoid creation of artefacts.
Furthermore, due to budgetary reasons, the repetition cycle of ALS surveys typically is not short enough to enable detection of the effects of surface forming of certain geomorphic processes.
In order to cope with that Terrestrial Laser Scanning (TLS) is also increasingly applied for fast data capture of the surface on local scale, e.g., in detection and monitoring of mass movements, glacial, erosional and sedimentary deposition studies requiring high accuracy and frequent repetition.
The resolution and accuracy provided by LiDAR DTMs are especially valuable in low-relief areas like floodplains. The application possibilities of such DTMs, for instance, in flood control are widespread. Repeated LiDAR surveys may also contribute to the understanding and monitoring of the floodplain sedimentation processes, river dynamics, and quantification of erosion and sedimentation.
Likewise, for high-relief areas, e.g., in Alpine environment the ALS surveys may also contribute to the monitoring of mass movements, erosional processes, transport of debris and incipient motion of slopes.
The wealth of laser scanning-derived DTMs can be used for geomorphic analyses in various forms (point cloud, TIN, grid) for analysis in flood-endangered regions, for natural hazard analyses and are almost unbeatable in surface modelling of mountainous and karstic areas. They are also highly applicable in environmental change studies concerning the change in snow and ice coverage, soil creep, etc.

The application of both laser scanning techniques results in data sets characterised by enormous data sizes, extremely high accuracy (up to cm-scale) and very high resolution. These properties compensate for the efforts invested in the data processing, however it means new challenges for the geomorphic evaluation. Especially in case of multitemporal studies the fusion of data from various data acquisition techniques, varying resolution and differing data acquisition conditions (e.g., seasonal variation of canopy) requires special attention. In geomorphology the informative value of these data can be used only if geomorphologists, data acquisition specialists and data processing experts closely co-operate to extract the geomorphological information contained in the data.
This session has been successful in strengthening the connection between the geomorphological research and LiDAR acquisition technology. The session is intended to facilitate the cooperation of specialists working in this field with the potential users in geomorphology in the widest sense.

Contributions concerning processing techniques as well as geomorphic application examples are welcome. Beside of that studies on applicability of laser scanning-derived DSMs and DTMs in various environments and at various scales, data fusion examples of ALS and TLS data with other data sources, case studies of problematic data sets, untypical applications like LiDAR geomorphic studies in urban areas, are also covered by the session.

In order to facilitate the communication within the community applying LiDAR in geomorphology, similarly to the previous years, we intend to use the full range of presentation options newly introduced to EGU General Assembly. We also encourage early stage researchers to present their studies.

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