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

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Frequently anticipated questions:

What does this data set describe?

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
Abstract:
Presented here are point clouds derived from aerial photography collected by the U.S. Geological Survey (USGS) using an oblique plane-mounted camera system, covering approximately 13 km of the coastline near Big Sur, California. These point clouds are referenced to previously published lidar data and contain RGB information as well as XYZ. Point cloud coordinates are in NAD83 UTM Zone 10 meters. Imagery was collected with a Nikon D800 camera in RAW format and processed using structure-from-motion photogrammetry with Agisoft PhotoScan version 1.7 through 2.0. Point clouds were clipped to an area of interest (AOI) using LASTools. The AOI was created in ArcGIS Pro 3.3.1.
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.
  1. How might this data set be cited?
    Dow, Helen W., Warrick, Jonathan A., and Ritchie, Andrew C., 20250903, 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: data release DOI:10.5066/P13FEC44, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Dow, Helen W., Warrick, Jonathan A., and Ritchie, Andrew C., 2025, Topographic point clouds and change analysis for the Big Sur, California coastline from structure-from-motion photogrammetry from aerial photographs, 2017–2023: data release DOI:10.5066/P13FEC44, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    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.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -121.659423
    East_Bounding_Coordinate: -121.583232
    North_Bounding_Coordinate: 36.147515
    South_Bounding_Coordinate: 36.042181
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 25-Jan-2017
    Ending_Date: 08-Jun-2023
    Currentness_Reference:
    ground condition at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: point cloud digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      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.
      This is a Point data set.
    2. What coordinate system is used to represent geographic features?
      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 coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.01
      Ordinates (y-coordinates) are specified to the nearest 0.01
      Planar coordinates are specified in METERS
      The horizontal datum used is NAD83.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
      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
  7. How does the data set describe geographic features?
    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), color (red, blue, and green components), and confidence (an alignment product).
    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)

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Helen W. Dow
    • Jonathan A. Warrick
    • Andrew C. Ritchie
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: PCMSC Science Data Coordinator
    2885 Mission Street
    Santa Cruz, CA
    United States

    831-427-4747 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

Data were collected as part of ongoing monitoring of the California coastline within the USGS Remote Sensing Coastal Change (RSCC) Project.

How was the data set created?

  1. From what previous works were the data drawn?
    PCMSC PlaneCam photographs (source 1 of 2)
    U.S. Geological Survey, 20230221, PCMSC PlaneCam – Field data from periodic and event-response surveys of the U.S. West Coast..

    Online Links:

    Other_Citation_Details:
    https://cmgds.marine.usgs.gov/data-services/rscc/pcmsc_planecam/pcmsc_planecam_metadata.xml
    Type_of_Source_Media: Digital
    Source_Contribution:
    We used aerial imagery to produce point clouds using photogrammetry techniques.
    2018 lidar (source 2 of 2)
    U.S. Geological Survey, 20210205, 2018 FEMA Lidar: Region 9, CA Point Cloud files with Orthometric Vertical Datum North American Vertical Datum of 1988 (NAVD88) using GEOID18.

    Online Links:

    Other_Citation_Details:
    https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9269/2018_ca_fema_region9_metadata.xml
    Type_of_Source_Media: Digital
    Source_Contribution: ground control
  2. How were the data generated, processed, and modified?
    Date: 2023 (process 1 of 3)
    Aerial imagery for the study area were downloaded. Imagery had previously been collected using a USGS platform built to collect survey-grade Global Navigation Satellite System (GNSS) data and simultaneously collect images at 1-second intervals on a Nikon D810 camera mounted obliquely on a Cessna 210. Data sources used in this process:
    • PCMSC PlaneCam Photographs
    Date: 2023 (process 2 of 3)
    These process steps following the general technique presented in Warrick and others (2017) and the detailed procedures outlined in Over and others (2021) 1. Geotagged images containing imagery from the survey area were imported into Agisoft Photoscan Professional v. 1.7-2.0 software using the 'Add photos' tool. 2. PPK post-processed positions were imported for all flights where data were available (accuracy set to 10 cm horizontal 15 cm vertical). 3. The photos were processed through an initial alignment and optimization procedure using the following settings: Alignment - Accuracy: 'High'; Pair selection: 'Reference, generic'; Key point limit: 0 (unlimited); Tie point limit: 0 (unlimited). Optimization - Lens-calibration parameters f, cx, cy, k1, k2, k3, p1, and p2 were included; b1, b2, and higher-order parameters k4, p3, and p4 were not. 4. The sparse point cloud (tie points; created as a result of photo alignment and optimization) was edited using an iterative error-reduction procedure to filter the data. This was done in several iterations of a process called "Gradual Selection" to first reduce reconstruction uncertainty (to a unitless value of 10) and then projection accuracy (to a weighted value of 6). 5. Synthetic ground control points (SGCPs) were created from identifiable, stable ground features (for example, buildings, road intersections) clearly visible in both lidar and imagery. 6. SGCP location files, which assigned coordinates (northing, easting, and elevation in UTM Zone 10 North meters in NAD83 and NAVD88 coordinate systems) were imported, markers were manually placed on photos where they were visible, and another optimization procedure was performed. 7. Another round of "Gradual Selection" was done to reduce the reprojection error (to a value of 0.3 pixels). 8. Confidence filtering was done to remove points with low confidence (confidence 0-4 removed). 9. A dense point cloud was then created with the parameters "High" quality and "Mild" depth filtering. Data sources used in this process:
    • PCMSC PlaneCam photographs
    • 2018 lidar
    Date: 2023 (process 3 of 3)
    The dense point cloud was exported in LAZ format and clipped to a polygon of the study area using lastools
  3. What similar or related data should the user be aware of?
    Over, Jin-Si R., Ritchie, Andrew C., Kranenburg, Christine J., Brown, Jenna A., Buscombe, Daniel D., Noble, Tom, Sherwood, Christopher R., Warrick, Jonathan A., and Wernette, Phillipe A., 2021, Processing coastal imagery with Agisoft Metashape Professional Edition, version 1.6-Structure from motion workflow documentation.

    Online Links:

    Other_Citation_Details:
    Over, J.R., Ritchie, A.C., Kranenburg, C.J., Brown, J.A., Buscombe, D., Noble, T., Sherwood, C.R., Warrick, J.A., and Wernette, P.A., 2021, Processing coastal imagery with Agisoft Metashape Professional Edition, version 1.6—Structure from motion workflow documentation: U.S. Geological Survey Open-File Report 2021–1039, 46 p., https://doi.org/10.3133/ofr20211039.
    Warrick, Jonathan A., Ritchie, Andrew C., Adelman, Gabrielle, Adelman, Kenneth, and Limber, Patrick W., 20170101, New Techniques to Measure Cliff Change from Historical Oblique Aerial Photographs and Structure-from-Motion Photogrammetry.

    Online Links:

    Other_Citation_Details:
    Warrick, J.A.; Ritchie, A.C.; Adelman, G.; Adelman, K., and Limber, P.W., 2017. New techniques to measure cliff change from historical oblique aerial photographs and Structure-from-Motion photogrammetry: Journal of Coastal Research 33(1), 39-55, (1 January 2017). https://doi.org/10.2112/JCOASTRES-D-16-00095.1.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    No formal attribute accuracy tests were conducted
  2. How accurate are the geographic locations?
    Ground control was derived from three photo- and lidar-identifiable, stable locations that were dispersed across the length of coastline analyzed. These synthetic ground control points consisted of the centers of physical structures and one point of transition between older road and freshly paved and painted road. Positions for these locations were derived from 2018 airborne lidar point data. The vertical and horizontal accuracies for these positions were assumed to be 0.25 m for the lidar-derived data. The lidar-derived data include the additional uncertainty of accurately matching the irregularly spaced lidar points to the photo-identifiable points, which is difficult to measure, but estimated to be an additional 0.25 m, resulting in a total estimated 3D uncertainty of 0.5 m.
  3. How accurate are the heights or depths?
    Ground control was derived from three photo- and lidar-identifiable, stable locations that were dispersed across the length of coastline analyzed. These synthetic ground control points consisted of the centers of physical structures and one point of transition between older road and freshly paved and painted road. Positions for these locations were derived from 2018 airborne lidar point data. The vertical and horizontal accuracies for these positions were assumed to be 0.25 m for the lidar-derived data. The lidar-derived data include the additional uncertainty of accurately matching the irregularly spaced lidar points to the photo-identifiable points, which is difficult to measure, but estimated to be an additional 0.25 m, resulting in a total estimated 3D uncertainty of 0.5 m.
  4. Where are the gaps in the data? What is missing?
    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.
  5. How consistent are the relationships among the observations, including topology?
    Coordinates recorded for each point in the point cloud describe discrete positions in space and the visual reflectance (in RGB values) at the time of capture. 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 (Digital Elevation Model (DEM) and Orthomosaic). 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.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
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.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - CMGDS
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov
  2. What's the catalog number I need to order this data set? These data are available in LAZ format contained in zip folders organized by flight dates accompanied by CSDGM FGDC-compliant metadata.
  3. What legal disclaimers am I supposed to read?
    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.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: This zip file contains 5 point clouds in LAZ format (LAS 1.2 specification) for flight dates 20170125, 20170222, 20170308, 20170405, and 20170519. in format LAZ (version LAS 1.2) Size: 1900
      Network links: https://doi.org/10.5066/P13FEC44
      Data format: This zip file contains 5 point clouds in LAZ format (LAS 1.2 specification) for flight dates 20170627, 20171221, 20180129, 20180307, and 20180605. in format LAZ (version LAS 1.2) Size: 1700
      Network links: https://doi.org/10.5066/P13FEC44
      Data format: This zip file contains 5 point clouds in LAZ format (LAS 1.2 specification) for flight dates 20180910, 20190223, 20190311, 20190610, and 20191031. in format LAZ (version LAS 1.2) Size: 1800
      Network links: https://doi.org/10.5066/P13FEC44
      Data format: This zip file contains 4 point clouds in LAZ format (LAS 1.2 specification) for flight dates 20200125, 20200319, 20200705, and 20210110. in format LAZ (version LAS 1.2) Size: 1500
      Network links: https://doi.org/10.5066/P13FEC44
      Data format: This zip file contains 4 point clouds in LAZ format (LAS 1.2 specification) for flight dates 20210129, 20210326, 20211218, and 20220204. in format LAZ (version LAS 1.2) Size: 1800
      Network links: https://doi.org/10.5066/P13FEC44
      Data format: This zip file contains 6 point clouds in LAZ format (LAS 1.2 specification) for flight dates 20220609, 20230101, 20230106, 20230112, 20230123, and 20230208. in format LAZ (version LAS 1.2) Size: 1800
      Network links: https://doi.org/10.5066/P13FEC44
      Data format: This zip file contains 4 point clouds in LAZ format (LAS 1.2 specification) for flight dates 20230302, 20230313, 20230317, and 20230608. in format LAZ (version LAS 1.2) Size: 1100
      Network links: https://doi.org/10.5066/P13FEC44
    • Cost to order the data: None.

  5. What hardware or software do I need in order to use the data set?
    This zip file contains point cloud data 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.

Who wrote the metadata?

Dates:
Last modified: 03-Sep-2025
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA
United States

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/DataReleases/CMGDS_DR_tool/DR_P13FEC44/BigSur_TopographicPointClouds_metadata.faq.html>
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