Topographic change detection at select archeological sites in Grand Canyon National Park, Arizona, 2007-2010

Abstract

This report and any updates to it are available online at: http://pubs.usgs.gov/sir/2012/5133/ For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment-visit http://www.usgs.gov or call 1-888-ASK-USGS For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted material contained within this report. Datum InformationHorizontal coordinate information was collected referenced to the North American Datum of 1983 (NAD83) and projected to Arizona Central Zone 0202 State Plane coordinates expressed in meters. For the purpose of protecting the sensitive nature of the archeological sites, all coordinates have been translated to a fictitious origin, still expressed in meters.Vertical coordinate information is referenced to the North American Datum of 1983 (NAD83) ellipsoid height, expressed in meters.Elevation, as used in this report, refers to distance above the vertical datum.This page intentionally left blank. Topographic Change Detection at Select AbstractHuman occupation in Grand

Illuminating wildfire erosion and deposition patterns with repeat terrestrial lidar

“…Terrestrial laser scanning (TLS) is a useful technology for rapid, detailed measurement of erosion/deposition patterns [ Collins and Sitar , ; Wheaton et al , ; Day et al , ; Lague et al , ] and changes in surface roughness [ Sankey et al , ; Lague et al , ]. Because the data acquisition process is relatively efficient, noninvasive [ Collins et al , ], and suitable for steep terrain [ Staley et al , ]; repeat surveys over a period of weeks to years make it possible to detect centimeter‐scale changes in topography over time [ Wheaton et al , ; Schmidt et al , ; Soulard et al , ; Staley et al , ]. Studies in the steep shrublands of the San Gabriel mountains, California, have demonstrated the potential of TLS to quantify post‐fire morphologic change [ Schmidt et al , ; Staley et al , ].…”

Comparing Two Methods of Surface Change Detection on an Evolving Thermokarst Using High-Temporal-Frequency Terrestrial Laser Scanning, Selawik River, Alaska

“…The form and components of this equation are similar to the one used by Brasington et al [23] for propagating uncertainty to change detection work with DoD analysis; however, the equation of Collins et al [29] deals more explicitly with the sources of error involved in point cloud change detection. The uncertainty of the OPUS positions used in 2011 and 2012 are not considered in this error analysis, because inter-year comparisons of the feature are not undertaken in this study.…”

“…Two error analysis techniques were used to calculate a change detection threshold to be used in conjunction with CbD to differentiate noise from measurable topographic change. Collins et al [29] proposed an additive RMS error analysis technique to estimate the accumulated errors associated with (1) the GPS solutions used for georeferencing; (2) the instrument; (3) the georeferencing itself; and (4) the registration of multiple point clouds. This error estimate can then be used to assess whether measured changes between two point clouds are significant.…”

“…This error estimate can then be used to assess whether measured changes between two point clouds are significant. For this study, Collins et al [29] equation was modified, because only one scan position was used to generate all point clouds, which allows the registration error to be dropped from the equation such that:…”

“…This method has been used with success to investigate structural and surface deformation [27,28]. Collins et al [29] have used similar techniques to investigate land surface change in the Grand Canyon, AZ. It should also be noted that Wheaton et al [10] and Glennie et al [30] used triangulated irregular networks, a meshing method, as an intermediate step when creating DEMs of their study area.…”