OpenTopography Blog

Information and discussion related to high-resolution LiDAR topography for the Earth sciences

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Category: TLS

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Fall AGU Special Session on Ground Based Geodetic Techniques and Science Applications

Posted on Tue, August 10, 2010 by C. Crosby in Meetings • TLS

Session announcements for the fall American Geophysical Union (AGU) meeting in San Francisco are beginning to appear.  The following session on ground based geodetic techniques includes an emphasis on terrestrial laser scanning:

Dear Colleagues:

We would like to bring to your attention the following special session on Ground Based Geodetic Techniques and Science Applications to be held at the 2010 Fall AGU Meeting in San Francisco, December 13 - 17:

Ground Based Geodetic Techniques and Science Applications
Ground-based geodesy is a rapidly expanding and evolving technology. Tools such as terrestrial laser scanners (TLS) and/or ground-based radars (GBR) promise to expand our detailed understanding of the fundamental processes that drive a broad range of spatial (3D) and temporal (4D) science applications. We invite contributions that discuss both the technical aspects of the technology and process-based geoscience studies using ground-based geodetic tools such as, but not limited to, TLS and GBR. What are the strengths, weaknesses, and limitations of the technologies? How is the technology being used to address static and dynamic scientific problems? We encourage contributions from a wide range of disciplines.

http://www.agu.org/meetings/fm10/program/scientific_session_search.php?show=detail&sessid=269

Best regards,

Benjamin Brooks, David Phillips, and Gerald Bawden - Session conveners

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Geoscience Applications of High-Resolution Digital Topography in Arizona

Posted on Sun, August 01, 2010 by C. Crosby in News • Publications • Research • TLS

The latest edition of the Arizona Geological Survey’s online Arizona Geology magazine has a nice article on recent applications of airborne and terrestrial LiDAR to geoscience research in Arizona written by David Haddad, a graduate student in ASU’s Active Tectonics, Quantitative Structural Geology and Geomorphology research group.  For his MS research, David used LiDAR data from both airborne and terrestrial platforms to characterize the geomorphic settings of precariously balanced rocks in the Granite Dells near Prescott, AZ.  Precariously balanced rocks (PBRs) can be used as negative indicators of strong ground motion caused by earthquakes, and their spatial distribution provides an indication of the intensity of ground shaking in a given location.  For more on PBRs, see David’s other Arizona Geology article: Nature’s Balanced Seismometers.

David’s article provides a nice overview of LiDAR technology, a few nice graphics like the one above, and a good intro to how these data have been applied to his PBR research in Arizona.

Arizona Geology article: High-Resolution Digital Topography in Arizona

Via: Lee Allison’s Arizona Geology blog

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2010 GSA Annual Meeting - Applications of Airborne and Terrestrial Lidar

Posted on Fri, June 25, 2010 by C. Crosby in Meetings • TLS

This GSA 2010 LiDAR session announcement went out this morning via various listservs.  This session, coupled with the accompanying Pardee Keynote Symposium and the Terrestrial Laser Scanning: Applications in Geology and Geomorphology session that was announced previously, means that GSA is shaping up to be a great meeting for Earth science applications of LiDAR.  I’ll be giving a talk in the Pardee session.  Hope to see you there!

We would like to draw your attention to the following Topical Session at the 2010 GSA Annual Meeting in Denver, Colorado (Oct. 31st - Nov. 3rd):

T32. Seeing the True Shape of Earth’s Surface: Applications of Airborne and Terrestrial LiDAR in the Geosciences (Oral and Poster)

High-resolution lidar data are now becoming available over large areas of earth’s surface. This session will examine how these highly detailed images of the landscape provide unprecedented opportunities for qualitative and quantitative analysis of earth processes. We invite presentations from any application of lidar in the geosciences. The session is being co-sponsored by the GSA Engineering Geology , Structural Geology and Tectonics, Quaternary Geology and Geomorphology, Sedimentary Geology , Geoinformatics, and Geophysics Divisions and will accompany a Pardee Keynote Symposium on the same topic.

Conveners:
Ian Madin (ian.madin@dogami.state.or.us)
Kurt Frankel (kfrankel@gatech.edu)

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Terrestrial Laser Scanning: Applications in Geology and Geomorphology session at GSA 2010

Posted on Sun, May 23, 2010 by C. Crosby in Meetings • TLS

TLS session at the 2010 Geological Society of America Meeting in Denver, CO announced.  Via the GEOMORPHLIST:

Dear Colleague-

With apologies for cross-posting, I encourage you to submit abstracts for Session T.125 Terrestrial Laser Scanning: Applications in Geology and Geomorphology at GSA 2010 in Denver, Colorado.  This session is co-sponsored by the GSA Engineering Geology Division and the GSA Quaternary Geology and Geomorphology Division.

Contributions describing the applications of this technology, as well as discussions of critical issues associated with the implementation of TLS to geomorphic and geologic studies are encouraged.

Feel free to contact me if you have any questions.

Thanks,

Dennis M. Staley
U.S. Geological Survey
1711 Illinois St
Golden, CO 80401
303.273.8568
dstaley@usgs.gov

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Session Description:

The characterization of surface features at multiple spatial scales is fundamental to understanding the process-form interactions and to the progression of geomorphic and geologic research.  Terrestrial laser scanning (TLS, commonly referred to as terrestrial LiDAR) permits the development of topographic data at unprecedented spatial and temporal resolutions over large areas. TLS data in the form of point clouds and/or digital terrain models are used to assess topographic boundary conditions, enhance geomorphological mapping by identifying spatial patterns and morphometric changes in landforms at various spatial scales, quantify rates of sediment transport through morphological DTM of differences approaches, and serve as benchmark datasets to test numerical and physical models of surface processes.  Repeat TLS surveys also permit the detection of fine scale changes in topography associated with geomorphic processes.

Advancing our understanding of geomorphic processes by incorporating TLS methodology presents new challenges: evaluation of scalar variability and dependencies in process-form relationships; linking process mechanics to high resolution topographic data, and data storage and transfer issues are also important considerations in TLS analytics.  While similar topics have been previously addressed at professional conferences (e.g. the LiDAR oral and poster sessions at the previous GSA meeting), these sessions have largely focused upon airborne LiDAR applications. Very little discussion has centered on TLS applications.  The growing popularity of TLS use in the geosciences necessitates a session devoted to the development of TLS methodology and data analysis in geology and geomorphology.  This session seeks to bring together researchers using TLS to identify and discuss critical issues concerning the application of TLS in the geosciences, as well as highlight cutting edge research that utilizes this methodology to further our understanding of the processes that sculpt the surface of the Earth.

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Filtering vegetation from Terrestrial Laser Scanning data using the Point2Grid tool

Posted on Fri, February 26, 2010 by C. Crosby in Software • TLS

Max Wilkinson, a PhD student in the Dept. of Earth Sciences at Durham University in the UK, recently sent us a link to a video of a seminar he gave on methods of vegetation filtration from Terrestiral Laser Scanning (TLS) data using the Points2Grid tool developed by the OpenTopography team (originally developed with GEON funding).  Points2Grid is a Windows application that implements the exact same DEM generation algorithm that is used in the OpenTopography point cloud processing system.  It was developed to allow users to get the same DEM generation capabilities as are available in OpenTopography for non-hosted data. 

Dealing with vegetation in TLS scanner data can be a significant problem, and Max shows in the video how he is able to use the MIN surface feature in P2G to remove much of the vegetation from the scan.  Points2Grid is not technically designed to filter vegetation, but the minimum surface function can act as a low budget filter.  P2G is also handy for reducing the complexity of the point cloud data down to something more manageable for analysis.  In this case, Max has much higher shot densities than he needs to construct a surface from the data, and P2G helps to reduce the amount of data he is working with:

From the TLS perspective, I’m finding P2G is tremendously useful for distilling large pointsets down to a size whereby the computing time required to test various interpolation methods becomes bearable! I had previously spent many hours waiting to see the output of an interpolation based on millions of points, only to find the parameters I used were not quite right. With the reduced computing time I’m now able to run more interpolations in various programs with a range of different parameters to see the results. I’m now using arcGIS for interpolations of TLS data, rather than just goCAD. For example, I’ve just finished a flow routing analysis of footwall drainage in arcGIS. A big thank you to the team for making P2G available!

Screen capture of the video:

You can download the video from Max’s page here: Vegetation Removal.avi (124 MB download). 

I had difficulties getting the file to play in Quicktime on a Mac, but the video played perfectly in open source (free) VLC player.  You may also need this ffdshow codec provided by Max.

The GEON Points2Grid tool can be downloaded via the lidar.asu.edu site.  I recommend reading the P2G Instructions / Help doc and also looking at the this page on how the search radius parameter in P2G works.

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Close range morphological measurement for the earth sciences

Posted on Mon, December 08, 2008 by C. Crosby in TLS

Here is an announcement related to terrestrial laser scanning that should be of interest to the OpenTopography community. The announcement came through on the GEOMOD-LIDAR-L listserv this morning:

Dear Colleagues,

ISPRS V/6: Close range morphological measurement for the earth sciences.

I’m pleased to announce the formation of an International Society for Photogrammetry and Remote Sensing (ISPRS) working group (V6) to promote and coordinate the use of modern geomatic techniques (terrestrial laser scanning and close range digital photogrammetry) for the measurement of natural objects. This should be of interest to a wide spectrum of researchers involved in 3D reconstruction, modelling and quantitative earth science research. The following fields are just an example of those within the broader earth science discipline: geomorphology, geology, glaciology, hydrology, agriculture, forestry, surface roughness and climate change studies.

For further details contact either myself, Jim Chandler j.h.chandler@lboro.ac.uk (Chair), or Rene Wackrow r.wackrow@lboro.ac.uk (secretary). Please note that involvement/membership is free and open to all.

Please circulate this announcement to colleagues who may be interested, and apologies for any cross-posting.

Best regards,

Simon Buckley
Co-chair, ISPRS Working Group V/6

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Airborne and terrestrial LiDAR coordination for The Great Southern California ShakeOut

Posted on Thu, November 13, 2008 by C. Crosby in News • TLS

Today at 10 am The Great Southern California ShakeOut staged an Mw=7.8 earthquake on the southern San Andreas Fault to raise public awareness of earthquake hazards and to allow public responders and the scientific community to practice their response to such an event.  As part of the scientific response, UNAVCO is coordinating community equipment deployment and data acquisition activities via their Great Southern California ShakeOut Response discussion forum.  A sub-forum, coordinated by David Phillips, is tracking the airborne and terrestrial LiDAR response to the earthquake.  As of 12:23 pm (CA time), TLS resources from University of New Mexico LiDAR Lab and NCALM are availble to respond to the event.  NCALM and UT Austin Center for Space Research have also confirmed that they could respond with airborne scanners and aircraft.

LiDAR acquisition immediately following a large, ground-rupturing earthquake on the San Andreas system, will be of great importance to preserve slip distribution, offset features and to provide a post-earthquake snap-shot of the landscape that could then be differenced with the recently acquired B4 or GeoEarthScope LiDAR topography datasets to provide information about near-field deformation along the fault rupture.

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