Point clouds showing erosion in an approximately 13 km long section of the Big Sur coast, California, between two flights and projected onto topography from the second flight

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Metadata:

Identification_Information
Data_Quality_Information
Spatial_Data_Organization_Information
Spatial_Reference_Information
Entity_and_Attribute_Information
Distribution_Information
Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: Helen W. Dow
Originator: Jonathan A. Warrick
Originator: Andrew C. Ritchie
Publication_Date: 20250903
Title:

Point clouds showing erosion in an approximately 13 km long section of the Big Sur coast, California, between two flights and projected onto topography from the second flight

Geospatial_Data_Presentation_Form: point cloud digital data
Series_Information:

Series_Name: data release
Issue_Identification: DOI:10.5066/P13FEC44

Publication_Information:

Publication_Place:

Pacific Coastal and Marine Science Center, Santa Cruz, California

Publisher: U.S. Geological Survey

Online_Linkage: https://doi.org/10.5066/P13FEC44
Online_Linkage:

https://cmgds.marine.usgs.gov/data-releases/datarelease/10.5066-P13FEC44/

Larger_Work_Citation:

Citation_Information:

Originator: Helen W. Dow
Originator: Jonathan A. Warrick
Originator: Andrew C. Ritchie
Publication_Date: 2025
Title:

Topographic point clouds and change analysis for the Big Sur, California coastline from structure-from-motion photogrammetry from aerial photographs, 2017–2023

Series_Information:

Series_Name: data release
Issue_Identification: DOI:10.5066/P13FEC44

Publication_Information:

Publication_Place:

Pacific Coastal and Marine Science Center, Santa Cruz, California

Publisher: U.S. Geological Survey

Other_Citation_Details:

Suggested Citation: Dow, H.W., Warrick, J.A., and Ritchie, A.C., 2025, Topographic point clouds and change analysis for the Big Sur, California coastline from structure-from-motion photogrammetry from aerial photographs, 2017–2023: U.S. Geological Survey data release, https://doi.org/10.5066/P13FEC44.

Online_Linkage: https://doi.org/10.5066/P13FEC44

Description:

Abstract:

Presented here are point clouds of approximately 13 km of the Big Sur coastline each showing erosion (as positive values) between two dates. The point cloud coordinates reflect topography at the later date. Change detection was computed using point clouds published in this data release and developed with structure-from-motion on aerial photography collected by the U.S. Geological Survey (USGS) using an oblique plane-mounted camera system. Ground points were identified in these point clouds using LAStools and manual reclassification of some protruding rocks as ground. Non-ground points were then removed, and the point clouds were clipped to an area of interest (AOI) of the cliff face using LASTools. We used the Multiscale Model-to-Model Cloud Comparison (M3C2) tool to calculate change in the cliff face between two flights. The M3C2 point cloud is a subsampled (at 0.25-m resolution) version of the point cloud of the second flight and M3C2 distances reflect erosion that occurred between the previous flight and this flight. This point cloud was then filtered using a combination of the Visible Atmospherically Resistant Index (VARI) and manual assessment to eliminate changes that do not reflect erosion, such as vegetation changes. It was then additionally filtered to include only points that the M3C2 algorithm considered significant (low uncertainty). Point cloud contains XYZ data and the following scalar fields: G-R/G+R-B (VARI), M3C2 distance, distance uncertainty, and significant change. Point cloud coordinates are in NAD83 UTM Zone 10 meters. The AOI was created in ArcGIS Pro 3.3.1. M3C2 distances, VARI calculation, and filtering were calculated in CloudCompare v2.12.4. Note that some flight dates represented in the topographic point cloud dataset will not have an associated M3C2 file because the product showed no erosion but substantial vegetation noise and was thus excluded.

Purpose:

Data were produced to investigate the magnitude, patterns, and drivers of seacliff erosion in Big Sur as part of the USGS Remote Sensing Coastal Change (RSCC) Project.

Supplemental_Information:

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 Federal Geographic Data Committee-compliant metadata file is intended to document the dataset in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 20170125
Ending_Date: 20230608

Currentness_Reference: ground condition

Status:

Progress: Complete
Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -121.659423
East_Bounding_Coordinate: -121.583232
North_Bounding_Coordinate: 36.147515
South_Bounding_Coordinate: 36.042181

Keywords:

Theme:

Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:68f40e93-c821-4c6d-bd55-9be4d716c831

Theme:

Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: geoscientificInformation
Theme_Keyword: elevation
Theme_Keyword: imageryBaseMapsEarthCover
Theme_Keyword: transportation

Theme:

Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) keywords
Theme_Keyword: geomorphology
Theme_Keyword: coastal change hazards topics
Theme_Keyword: coastal landsliding
Theme_Keyword: aerial and satellite photography
Theme_Keyword: agents of coastal change
Theme_Keyword: anthropogenic agents of coastal change
Theme_Keyword: coastal landslides
Theme_Keyword: coastal processes
Theme_Keyword: coastal sediment budget
Theme_Keyword: coastal zone management
Theme_Keyword: effects of coastal change
Theme_Keyword: human responses to coastal change
Theme_Keyword: hazards and disasters

Theme:

Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: landslides
Theme_Keyword: coastal processes
Theme_Keyword: hazards
Theme_Keyword: topography
Theme_Keyword: remote sensing
Theme_Keyword: aerial photography
Theme_Keyword: image analysis
Theme_Keyword: image collections

Theme:

Theme_Keyword_Thesaurus: Data Categories for Marine Planning
Theme_Keyword: Bathymetry and Elevation

Theme:

Theme_Keyword_Thesaurus: None
Theme_Keyword: U.S. Geological Survey
Theme_Keyword: USGS
Theme_Keyword: Coastal and Marine Hazards and Resources Program
Theme_Keyword: CMHRP
Theme_Keyword: Pacific Coastal and Marine Science Center
Theme_Keyword: PCMSC

Place:

Place_Keyword_Thesaurus: Geographic Names Information System (GNIS)
Place_Keyword: State of California
Place_Keyword: Monterey County
Place_Keyword: Big Sur

Place:

Place_Keyword_Thesaurus: Common geographic areas
Place_Keyword: United States
Place_Keyword: California
Place_Keyword: Central California Coastal
Place_Keyword: Monterey

Access_Constraints: No access constraints
Use_Constraints:

USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data.

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:

U.S. Geological Survey, Pacific Coastal and Marine Science Center

Contact_Person: PCMSC Science Data Coordinator

Contact_Address:

Address_Type: mailing and physical
Address: 2885 Mission Street
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060
Country: United States

Contact_Voice_Telephone: 831-427-4747
Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov

Native_Data_Set_Environment:

Microsoft Windows versions 10 and 11, Agisoft PhotoScan version 1.7 through 2.0, LASTools 180322 through 230327 were used to process data for this release.

Cross_Reference:

Citation_Information:

Originator: Dimitri Lague
Originator: Nicolas Brodu
Originator: Jérôme Leroux
Publication_Date: 2013
Title:

Accurate 3D comparison of complex topography with terrestrial laser scanner: Application to the Rangitikei canyon (N-Z)

Other_Citation_Details:

Lague D, Brodu N, Leroux J (2013) Accurate 3D comparison of complex topography with terrestrial laser scanner: Application to the Rangitikei canyon (N-Z). ISPRS J Photogramm Remote Sens 82:10–26. https://doi.org/10.1016/j.isprsjprs.2013.04.009

Online_Linkage: https://doi.org/10.1016/j.isprsjprs.2013.04.009

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report: No formal attribute accuracy tests were conducted

Logical_Consistency_Report:

Coordinates recorded for each point in the point cloud describe discrete positions in space at the time of capture and change in space between two data collection days. This final point cloud was checked for accuracy by rotating the point cloud to view from multiple angles to ensure that obvious spurious points do not cause artifacts in measurements or derivative products. Although some outlying points were eliminated during processing, there may still be points that do not represent ground features but are instead artifacts generated by erroneous tie points or spurious matches in the photogrammetric process.

Completeness_Report:

Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

Total 3D uncertainty is the same as the point cloud this change detection product is based on and is estimated at 0.5 m.

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

Total 3D uncertainty is the same as the point cloud this change detection product is based on and is estimated at 0.5 m.

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: Helen W. Dow
Originator: Jonathan A. Warrick
Originator: Andrew C. Ritchie
Publication_Date: 2025
Title:

Structure-from-motion point clouds of an approximately 13 km long section of the Big Sur coast, California for 33 flights between 2017-01-25 and 2023-06-08

Geospatial_Data_Presentation_Form: point cloud digital data
Online_Linkage: https://doi.org/10.5066/P13FEC44
Online_Linkage:

https://cmgds.marine.usgs.gov/data-releases/datarelease/10.5066-P13FEC44/

Type_of_Source_Media: Digital
Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 20170125
Ending_Date: 20230608

Source_Currentness_Reference: ground condition at time data were collected

Source_Citation_Abbreviation: Structure-from-motion point clouds
Source_Contribution:

We used these point clouds to measure erosion between each flight using the Multiscale Model-to-Model Cloud Comparison tool (Lague and others, 2013).

Process_Step:

Process_Description:

The point clouds were filtered and clipped to remove points representing tree canopy and not on the cliff face: 1. LAStools lasground tool was used on both point clouds to classify points as ground and non-ground points using the following command and settings: lasground_new -i temp_tiles\tile*.laz ^ -step 3.0 ^ -nature -hyper_fine ^ -bulge 1.0 ^ -offset 1.0 ^ -odir temp_tiles_ground -olaz ^ -cores %CORES% 2. Protruding rocks were reclassified as ground points using LAStools and a shapefile delineating the misclassified rocks. 3. Non-ground points were removed. 4. The point clouds were clipped to an AOI of the cliff face using LAStools.

Source_Used_Citation_Abbreviation: Structure-from-motion point clouds
Process_Date: 2025
Source_Produced_Citation_Abbreviation: processed point clouds

Process_Step:

Process_Description:

The Multiscale Model-to-Model Cloud Comparison tool (Lague and others, 2013) was used in CloudCompare v2.12.4 to calculate distance between the two point clouds, using the second-flight point cloud subsampled at 0.25-m resolution as core points and setting the diameter for normals calculation and projected cylinder to 3 m and maximum depth to 20 m.

Source_Used_Citation_Abbreviation: processed point clouds
Process_Date: 2025
Source_Produced_Citation_Abbreviation: full M3C2 point clouds

Process_Step:

Process_Description:

The M3C2 point clouds were filtered and clipped to reflect erosional events and not vegetation changes with the following steps: 1. The Visible Atmospherically Resistant Index or VARI, (G-R)/(G+R-B), was calculated on the core points using RGB values and interpolated onto the M3C2 point cloud. 2. Computed a histogram-based 20th percentile threshold of VARI values across the point cloud and removed all points whose VARI exceeds that threshold, effectively filtering to retain only the lowest 20 percent of VARI values. 3. All points not marked as significant change = 1 in the M3C2 output (such as, low uncertainty) were removed. 4. The final point cloud was manually checked against the first and second flight and the unfiltered M3C2 product. Any erosion that was filtered out was restored and any remaining erosion noise was removed. 5. Step 3 was repeated to remove any insignificant points that were spuriously added during the manual check.

Source_Used_Citation_Abbreviation: full M3C2 point clouds
Process_Date: 2025

Spatial_Data_Organization_Information:

Indirect_Spatial_Reference:

An approximately 13 km (8 miles) section of the Big Sur coast, Monterey County, California, from Anderson Canyon bridge to Gamboa Point.

Direct_Spatial_Reference_Method: Point

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Grid_Coordinate_System:

Grid_Coordinate_System_Name: Universal Transverse Mercator
Universal_Transverse_Mercator:

UTM_Zone_Number: 10
Transverse_Mercator:

Scale_Factor_at_Central_Meridian: 0.9996
Longitude_of_Central_Meridian: -123.0
Latitude_of_Projection_Origin: 0.0
False_Easting: 500000.0
False_Northing: 0.0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:

Abscissa_Resolution: 0.01
Ordinate_Resolution: 0.01

Planar_Distance_Units: METERS

Geodetic_Model:

Horizontal_Datum_Name: NAD83
Ellipsoid_Name: GRS 1980
Semi-major_Axis: 6378137.0
Denominator_of_Flattening_Ratio: 298.257222101

Vertical_Coordinate_System_Definition:

Altitude_System_Definition:

Altitude_Datum_Name:

North American Vertical Datum of 1988 (EPSG:5703), derived using GEOID18

Altitude_Resolution: 0.01
Altitude_Distance_Units: meters
Altitude_Encoding_Method:

Explicit elevation coordinate included with horizontal coordinates

Entity_and_Attribute_Information:

Overview_Description:

Entity_and_Attribute_Overview:

The attribute information associated with point cloud follows the LAZ file standard. Attributes include location (northing, easting, and elevation in the NAD83/UTM zone 10N (EPSG:26910) horizontal and NAVD88 vertical coordinate systems), VARI (G-R/G+R-B), and M3C2 outputs (M3C2 distance, distance uncertainty, and significant change).

Entity_and_Attribute_Detail_Citation:

American Society for Photogrammetry and Remote Sensing (ASPRS; 2013, https://www.asprs.org/committee-general/laser-las-file-format-exchange-activities.html) and Isenburg (2013, https://doi.org/10.14358/PERS.79.2.209)

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey - CMGDS

Contact_Address:

Address_Type: mailing and physical
Address: 2885 Mission Street
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060

Contact_Voice_Telephone: 831-427-4747
Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov

Resource_Description:

These data are available in LAZ format contained in a single zip file (BigSur_M3C2_PointClouds.zip) accompanied by CSDGM FGDC-compliant metadata.

Distribution_Liability:

Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: LAZ
Format_Version_Number: LAS 1.2
Format_Information_Content:

This zip file contains 27 point clouds in LAZ format (LAS 1.2 specification).

File_Decompression_Technique: Unzip. Data are compressed into a zip file.
Transfer_Size: 514.8

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: https://doi.org/10.5066/P13FEC44

Access_Instructions:

Data can be downloaded using the Network_Resource_Name link and scrolling down to the Location-Elevation Data section

Fees: None.

Technical_Prerequisites:

This zip file contains point clouds in LAZ format (LAS 1.2 specification). The user must have software capable of uncompressing the .zip compressed file and displaying or processing the .laz format file.

Metadata_Reference_Information:

Metadata_Date: 20250903
Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:

U.S. Geological Survey, Pacific Coastal and Marine Science Center

Contact_Person: PCMSC Science Data Coordinator

Contact_Address:

Address_Type: mailing and physical
Address: 2885 Mission Street
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060
Country: United States

Contact_Voice_Telephone: 831-427-4747
Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov

Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998

This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/DataReleases/CMGDS_DR_tool/DR_P13FEC44/BigSur_M3C2_metadata.html>