{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,23]],"date-time":"2025-10-23T16:50:28Z","timestamp":1761238228194,"version":"build-2065373602"},"reference-count":63,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2015,9,18]],"date-time":"2015-09-18T00:00:00Z","timestamp":1442534400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"PacTrans"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Monitoring unstable slopes with terrestrial laser scanning (TLS) has been proven effective. However, end users still struggle immensely with the efficient processing, analysis, and interpretation of the massive and complex TLS datasets. Two recent advances described in this paper now improve the ability to work with TLS data acquired on steep slopes. The first is the improved processing of TLS data to model complex topography and fill holes. This processing step results in a continuous topographic surface model that seamlessly characterizes the rock and soil surface. The second is an advance in the automated interpretation of the surface model in such a way that a magnitude and frequency relationship of rockfall events can be quantified, which can be used to assess maintenance strategies and forecast costs. The approach is applied to unstable highway slopes in the state of Alaska, U.S.A. to evaluate its effectiveness. Further, the influence of the selected model resolution and degree of hole filling on the derived slope metrics were analyzed. In general, model resolution plays a pivotal role in the ability to detect smaller rockfall events when developing magnitude-frequency relationships. The total volume estimates are also influenced by model resolution, but were comparatively less sensitive. In contrast, hole filling had a noticeable effect on magnitude-frequency relationships but to a lesser extent than modeling resolution. However, hole filling yielded a modest increase in overall volumetric quantity estimates. Optimal analysis results occur when appropriately balancing high modeling resolution with an appropriate level of hole filling.<\/jats:p>","DOI":"10.3390\/rs70912103","type":"journal-article","created":{"date-parts":[[2015,9,21]],"date-time":"2015-09-21T02:25:40Z","timestamp":1442802340000},"page":"12103-12134","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":32,"title":["To Fill or Not to Fill: Sensitivity Analysis of the Influence of Resolution and Hole Filling on Point Cloud Surface Modeling and Individual Rockfall Event Detection"],"prefix":"10.3390","volume":"7","author":[{"given":"Michael","family":"Olsen","sequence":"first","affiliation":[{"name":"School of Civil and Construction Engineering, Oregon State University, 101 Kearney Hall, Corvallis, OR 97331, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7659-7198","authenticated-orcid":false,"given":"Joseph","family":"Wartman","sequence":"additional","affiliation":[{"name":"Department of Civil and Environmental Engineering, University of Washington, 201 More Hall, Box 352700, Seattle, WA 98195, USA"}]},{"given":"Martha","family":"McAlister","sequence":"additional","affiliation":[{"name":"School of Civil and Construction Engineering, Oregon State University, 101 Kearney Hall, Corvallis, OR 97331, USA"}]},{"given":"Hamid","family":"Mahmoudabadi","sequence":"additional","affiliation":[{"name":"School of Civil and Construction Engineering, Oregon State University, 101 Kearney Hall, Corvallis, OR 97331, USA"}]},{"given":"Matt","family":"O\u2019Banion","sequence":"additional","affiliation":[{"name":"School of Civil and Construction Engineering, Oregon State University, 101 Kearney Hall, Corvallis, OR 97331, USA"}]},{"given":"Lisa","family":"Dunham","sequence":"additional","affiliation":[{"name":"Department of Civil and Environmental Engineering, University of Washington, 201 More Hall, Box 352700, Seattle, WA 98195, USA"}]},{"given":"Keith","family":"Cunningham","sequence":"additional","affiliation":[{"name":"International Artic Research Center, University of Alaska, Fairbanks, AK 99775, USA"}]}],"member":"1968","published-online":{"date-parts":[[2015,9,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Petley, D. (2012). Global patterns of loss of life from landslides. Geology.","DOI":"10.1130\/G33217.1"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1007\/s11069-010-9634-2","article-title":"Use of LIDAR in landslide investigations: A review","volume":"61","author":"Jaboyedoff","year":"2012","journal-title":"Nat. Hazards"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1002\/esp.3493","article-title":"State of science: Terrestrial laser scanner on rock slopes instabilities","volume":"39","author":"Jaboyedoff","year":"2014","journal-title":"Earth Surf. Process. Landf."},{"key":"ref_4","unstructured":"Kemeny, J., and Turner, A.K. Ground-Based LiDAR Rock Slope Mapping and Assessment. Available online: http:\/\/zh.scribd.com\/doc\/85760902\/GROUND-BASED-LiDAR-Rock-Slope-Mapping-and-Assessment#scribd."},{"key":"ref_5","unstructured":"Girardeau-Montaut, D., Roux, M., Marc, R., and Thibault, G. (2005, January 12\u201314). Change detection on point cloud data acquired with a ground laser scanner. Proceedings of the ISPRS Workshop Laser Scanning 2005, Enschede, the Netherlands."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"3425","DOI":"10.1080\/01431160601024234","article-title":"Terrestrial laser scanner to detect landslide displacement fields: A new approach","volume":"28","author":"Teza","year":"2007","journal-title":"Int. J. Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Rabatel, A., Deline, P., Jaillet, S., and Ravanel, L. (2008). Rockfalls in high-alpine rock walls quantified by terrestrial lidar measurements: A case study in the Mont Blanc area. Geophys. Res. Lett., 35.","DOI":"10.1029\/2008GL033424"},{"key":"ref_8","unstructured":"Alba, M., Roncoroni, F., and Scaioni, M. (2009, January 3\u20134). Application of TLS for change detection in rock faces. Proceedings of the ISPRS Laserscanning \u201809, Paris, France."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"365","DOI":"10.5194\/nhess-9-365-2009","article-title":"Detection of millimetric deformation using a terrestrial laser scanner: Experiment and application to a rockfall event","volume":"9","author":"Abellan","year":"2009","journal-title":"Nat. Hazards Earth Syst. Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"162","DOI":"10.1016\/j.geomorph.2010.03.016","article-title":"Detection and spatial prediction of rockfalls by means of terrestrial laser scanner monitoring","volume":"119","author":"Calvet","year":"2010","journal-title":"Geomorphology"},{"key":"ref_11","unstructured":"Alba, M., and Scaioni, M. (2010, January 21\u201324). Automatic detection of changes and deformation in rock faces by terrestrial laser scanning. Proceedings of the ISPRS Commission V Mid-Term Symposium, Newcastle upon Tyne, UK."},{"key":"ref_12","unstructured":"Stock, G.M., Luco, N., Harp, E.L., Collins, B.D., Reichenbach, P., Frankel, K., Matasci, B., Carrea, D., Jaboyedoff, M., and Oppikofer, T. (2012, January 3\u20138). Quantitative rock-fall hazard and risk assessment for Yosemite Valley, California, in Landslides and Engineered Slopes: Protecting Society through Improved Understanding. Proceedings of the 11th International Symposium on Landslides, Banff, AB, Canada."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Collins, B.D., and Stock, G.M. Lidar Based Rock-Fall Hazard Characterization of Cliffs, Available online: http:\/\/www.nps.gov\/yose\/learn\/nature\/upload\/Collins-Stock-2012-ASCE.pdf.","DOI":"10.1061\/9780784412121.309"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Ravanel, L., Deline, P., Lambiel, C., and Vincent, C. (2012). Instability of a high alpine rock ridge: The lower Ar\u00eate des Cosmiques, Mont Blanc Massif, France. Geogr. Ann. Ser. A Phys. Geogr.","DOI":"10.1111\/geoa.12000"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"702","DOI":"10.2112\/SI65-119.1","article-title":"Probabilistic coastal cliff collapse hazard from repeated terrestrial laser surveys: Case study from Mesnil Val (Normandy, northern France)","volume":"65","author":"Dewez","year":"2013","journal-title":"J. Coast. Res."},{"key":"ref_16","unstructured":"Lindenberg, R. (2013, January 9\u201310). Trends in detecting changes from repeated laser scanning data. Proceedings of the 2nd Joint International Symposium on Deformation Monitoring, Nottingham, UK."},{"key":"ref_17","unstructured":"D\u2019Amato, J., Guerin, A., Hantz, D., Rossetti, J.-P., and Jaboyedoff, M. (2014, January 15\u201319). Investigating rockfall frequency and failure configurations using Terrestrial Laser Scanner. Proceedings of the IAEG XII Congress, Torino, Italy."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"697","DOI":"10.1007\/s10346-013-0442-0","article-title":"Spatio-temporal analysis of rockfall pre-failure deformation using terrestrial LiDAR","volume":"11","author":"Royan","year":"2013","journal-title":"Landslides"},{"key":"ref_19","unstructured":"Girardeau-Montaut, D. Cloud Compare\u20143D Point Cloud and Mesh Processing Software. Available online: http:\/\/www.danielgm.net\/cc\/."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"04014040","DOI":"10.1061\/(ASCE)CP.1943-5487.0000328","article-title":"In-situ change analysis and monitoring through terrestrial laser scanning","volume":"29","author":"Olsen","year":"2015","journal-title":"J. Comput. Civil Eng."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1111\/j.1477-9730.2005.00315.x","article-title":"Combined digital photogrammetry and time-of-flight laser scanning for monitoring cliff evolution","volume":"20","author":"Lim","year":"2005","journal-title":"Photogramm. Record"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1016\/j.geomorph.2009.02.011","article-title":"Erosional processes in the hard rock coastal cliffs at Staithes, North Yorkshire","volume":"114","author":"Lim","year":"2010","journal-title":"Geomorphology"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"46","DOI":"10.2112\/JCOASTRES-D-09-00061.1","article-title":"Quantifying the controls and influence of tide and wave impacts on coastal rock cliff erosion","volume":"27","author":"Lim","year":"2011","journal-title":"J. Coast. Res."},{"key":"ref_24","first-page":"409","article-title":"Terrestrial laser scanning for quantitative rock fall hazard assessment","volume":"10","author":"Rosser","year":"2007","journal-title":"Landslides"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Rosser, N.J., Lim, M., Petley, D.N., Dunning, S., and Allison, R.J. (2007). Patterns of precursory rockfall prior to slope failure. J. Geophys. Res., 112.","DOI":"10.1029\/2006JF000642"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"363","DOI":"10.1144\/1470-9236\/05-008","article-title":"Terrestrial laser scanning for monitoring the process of hard rock coastal cliff erosion","volume":"38","author":"Rosser","year":"2005","journal-title":"Q. J. Eng. Geol. Hydrogeol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1061\/(ASCE)0733-9453(2009)135:4(161)","article-title":"Terrestrial laser scanning of extended cliff sections in dynamic environments: A parameter analysis","volume":"135","author":"Olsen","year":"2009","journal-title":"J. Surv. Eng."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"935","DOI":"10.5194\/nhess-9-935-2009","article-title":"Engineering monitoring of rockfall hazards along transportation corridors: Using mobile terrestrial LiDAR","volume":"9","author":"Lato","year":"2009","journal-title":"Nat. Hazards Earth Syst. Sci."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"416","DOI":"10.1016\/j.geomorph.2011.11.006","article-title":"Modeling cliff erosion using negative power law scaling of rockfalls","volume":"139\u2013140","author":"Barlow","year":"2012","journal-title":"Geomorphology"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1080\/19475705.2012.670668","article-title":"Optical techniques for multi-scale damage assessment in natural hazard analysis","volume":"4","author":"Olsen","year":"2013","journal-title":"Geomat. Nat. Hazards Risk"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1016\/j.enggeo.2012.07.001","article-title":"Magnitude\u2013frequency relation for rockfall scars using a terrestrial laser scanner","volume":"145\u2013146","author":"Santana","year":"2012","journal-title":"Eng. Geol."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Lee, M.L., and Jones, K.C. (2014). Landslide Risk Assessment, ICE Publishing.","DOI":"10.1680\/lra.58019"},{"key":"ref_33","first-page":"95","article-title":"Rockfall detection from LiDAR point clouds: A clustering approach using R","volume":"8","author":"Tonini","year":"2014","journal-title":"J. Spat. Inf. Sci."},{"key":"ref_34","first-page":"425","article-title":"Automatic rockfalls volume estimation based on terrestrial laser scanning data","volume":"2","author":"Carrea","year":"2015","journal-title":"Eng. Geol. Soc. Territ."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Turk, G., and Levoy, M. (1994, January 24\u201329). Zippered polygon meshes from range images. Proceedings of the 21st Annual Conference on Computer Graphics and Interactive Techniques, Orlando, FL, USA.","DOI":"10.1145\/192161.192241"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1109\/2945.817351","article-title":"The ball-pivoting algorithm for surface reconstruction","volume":"5","author":"Bernardini","year":"1999","journal-title":"IEEE Trans. Vis. Comput. Graph."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1109\/38.974519","article-title":"Building a digital model of michelangelo\u2019s florentine pieta","volume":"22","author":"Bernardini","year":"2002","journal-title":"IEEE Comput. Graph. Appl."},{"key":"ref_38","unstructured":"Medeiros, E., Velho, L., and Lopes, H. (2003, January 12\u201315). A topological framework for advancing front triangulation. Proceedings of the XVI Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI\u203203), Sao Carlos, Brazil."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Sheng, L., Li-qu, L., and Xiao-main, C. (2009, January 7\u20138). A new mesh growing surface reconstruction algorithm. Proceedings of the First International Workshop on Education Technology and Computer Science (ETCS), Wuhan, Hubei.","DOI":"10.1109\/ETCS.2009.736"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1061\/(ASCE)SU.1943-5428.0000101","article-title":"Hinged, pseudo-grid triangulation method for long, near linear cliff analysis","volume":"139","author":"Olsen","year":"2013","journal-title":"J. Surv. Eng."},{"key":"ref_41","unstructured":"National Geodetic Survey OPUS: Online Positioning User Service, Available online: http:\/\/www.ngs.noaa.gov\/OPUS\/."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1061\/(ASCE)SU.1943-5428.0000030","article-title":"New automated point-cloud alignment for ground based lidar data of long coastal sections","volume":"137","author":"Olsen","year":"2011","journal-title":"J. Surv. Eng."},{"key":"ref_43","unstructured":"Williams, K., Olsen, M.J., and Chin, A. (2012, January 19\u201323). Accuracy assessment of geo-referencing methodologies for terrestrial laser scan surveys. Proceedings of the ASPRS Annual Conference, Sacramento, CA, USA."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1061\/(ASCE)SU.1943-5428.0000072","article-title":"To Level or Not to Level: Laser scan inclination sensor evaluation","volume":"138","author":"Silvia","year":"2012","journal-title":"J. Surv. Eng."},{"key":"ref_45","unstructured":"Eberly, D. Least Squares Fitting of Data, Geometric Tools, LLC. Available online: http:\/\/www.geometrictools.com."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"629","DOI":"10.1364\/JOSAA.4.000629","article-title":"Closed-Form solution of absolute orientation using unit quaternions","volume":"4","author":"Horn","year":"1987","journal-title":"J. Opt. Soc. Am."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"1127","DOI":"10.1364\/JOSAA.5.001127","article-title":"Closed-Form solution of absolute orientation using orthonormal matricies","volume":"5","author":"Horn","year":"1988","journal-title":"J. Opt. Soc. Am."},{"key":"ref_48","unstructured":"Donato, G., and Belongie, S. Approximation Methods for Thin Plate Spline Mappings and Principal Warps. Available online: http:\/\/cseweb.ucsd.edu\/~sjb\/pami_tps.pdf."},{"key":"ref_49","unstructured":"Elonen, J. Thin Plate Spline Editor\u2014An Example Program in C++. Available online: http:\/\/elonen.iki.fi\/code\/tpsdemo\/."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Szeliski, R. (2011). Computer Vision: Algorithms and Applications, Springer Press.","DOI":"10.1007\/978-1-84882-935-0"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"2813","DOI":"10.3390\/rs5062813","article-title":"Comparing two methods of surface change detection on an evolving thermokarst using high-temporal-frequency terrestrial laser scanning, Selawik River, Alaska","volume":"5","author":"Barnhart","year":"2013","journal-title":"Remote Sens."},{"key":"ref_52","unstructured":"Zeiback, R., and Filin, S. (2007, January 12\u201314). Change detection via terrestrial laser scanning. Proceedings of the Laser Scanning 2007 and SilviLaser 2007, ISPRS, Espoo, Finland."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1145\/128749.128750","article-title":"A general approach to connected-component labeling for arbitrary image representations","volume":"39","author":"Dillencourt","year":"1992","journal-title":"J. ACM"},{"key":"ref_54","unstructured":"Fisher, R., Perkins, S., Walker, A., and Wolfart, E. Connected Components Labeling. Available online: http:\/\/homepages.inf.ed.ac.uk\/rbf\/HIPR2\/label.htm."},{"key":"ref_55","doi-asserted-by":"crossref","unstructured":"Plafker, G., and Berg, H.C. (1994). The Geology of Alaska, Geologic Society of America.","DOI":"10.1130\/DNAG-GNA-G1"},{"key":"ref_56","unstructured":"Trop, J.M., and Plawman, T.L. Bedrock Geology of the Glenn Highway from Anchorage to Sheep Mountain, Alaska: Mesozoic-Cenozoic Forearc Basin Development along an Accretionary Convergent Margin. Available online: http:\/\/archives.datapages.com\/data\/alaska\/data\/029\/029001\/1_akgs0290001.htm."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"224","DOI":"10.1139\/t98-106","article-title":"Magnitude and frequency of rock slides along the main transportation corridors of southwestern British Columbia","volume":"36","author":"Hungr","year":"1999","journal-title":"Can. Geotech. J."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"1303","DOI":"10.5194\/nhess-11-1303-2011","article-title":"Quantitative assessment of diffuse rock fall hazard along a cliff foot","volume":"11","author":"Hantz","year":"2011","journal-title":"Nat. Hazards Earth Syst. Sci."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1016\/S0012-821X(01)00589-1","article-title":"Power-law correlations of landslide areas in central Italy","volume":"195","author":"Guzzetti","year":"2002","journal-title":"Earth Planet. Sci. Lett."},{"key":"ref_60","unstructured":"National Parks Service (2010). Thornberry-Ehrlich, Denali National Park and Preserve: Geologic Resources Inventory Report, National Parks Service."},{"key":"ref_61","doi-asserted-by":"crossref","unstructured":"Wahrhaftig, C., and Black, R.F. (1958). Engineering Geology along Part of the Alaska Railroad.","DOI":"10.1525\/9780520310483-011"},{"key":"ref_62","doi-asserted-by":"crossref","unstructured":"Turner, A., and Schuster, R. (2012). Modeling and Prediction of Rockfall, Rockfall Characterization and Control, Transportation Research Board.","DOI":"10.17226\/27824"},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1061\/(ASCE)0733-9453(2005)131:4(135)","article-title":"Error models and propagation in directly georeferenced terrestrial laser scanner networks","volume":"131","author":"Lichti","year":"2005","journal-title":"J. Surv. Eng."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/7\/9\/12103\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T20:48:51Z","timestamp":1760215731000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/7\/9\/12103"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,9,18]]},"references-count":63,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2015,9]]}},"alternative-id":["rs70912103"],"URL":"https:\/\/doi.org\/10.3390\/rs70912103","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2015,9,18]]}}}