Synthetic ground control point locations used in photogrammetric processing of approximately 13 km of Big Sur coast from McWay Canyon to Gorda Point, 2017–2023

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Frequently anticipated questions:

What does this data set describe?

Title:
Synthetic ground control point locations used in photogrammetric processing of approximately 13 km of Big Sur coast from McWay Canyon to Gorda Point, 2017–2023
Abstract:
This portion of the data release presents locations for the synthetic ground control points (SGCPs) used during the structure-for-motion alignment process in Agisoft Metashape v1.7-2.0. The locations were chosen from lidar flown in early 2018 and then tagged in all imagery where they could be found. Following this procedure the alignment was reoptimized prior to development of the dense point clouds presented in this data release. The data contain the easting, northing, and elevation of the SGCPs taken from the lidar, as well as a description of each location. The data are presented in a comma-delimited text file.
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.
  1. How might this data set be cited?
    Dow, Helen W., Warrick, Jonathan A., and Ritchie, Andrew C., 20250903, Synthetic ground control point locations used in photogrammetric processing of approximately 13 km of Big Sur coast from McWay Canyon to Gorda Point, 2017–2023: 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, CA.

    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: -121.651322
    East_Bounding_Coordinate: -121.588558
    North_Bounding_Coordinate: 36.140484
    South_Bounding_Coordinate: 36.048398
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 22-Jan-2018
    Ending_Date: 21-Apr-2018
    Currentness_Reference:
    ground condition at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: CSV
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (3)
    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 0.1
      Ordinates (y-coordinates) are specified to the nearest 0.1
      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: 0.001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    Attribute Table
    Table containing attribute information associated with the dataset (Source: Producer defined)
    ID
    Point ID (Source: producer defined) A unique identification code for the point.
    easting
    Easting coordinate of data point relative to the North American Datum of 1983, projected in the Universal Transverse Mercator coordinate system, zone 10 north, in units of meters (EPSG:26910) (Source: Producer defined)
    Range of values
    Minimum:621340.6
    Maximum:627136.1
    Units:meters
    northing
    Northing coordinate of data point relative to the North American Datum of 1983, projected in the Universal Transverse Mercator coordinate system, zone 10 north, in units of meters (EPSG:26910) (Source: Producer defined)
    Range of values
    Minimum:3990238.2
    Maximum:4000372.7
    Units:meters
    elevation
    Elevation derived from the 2018 lidar. (Source: Producer defined)
    Range of values
    Minimum:48.1
    Maximum:100.5
    Units:meters
    location
    Description of the location. (Source: Producer defined) Text string describing the location (such as roof apex, road seam, dormer ridge).
    Entity_and_Attribute_Overview: The first line of the csv file is a header line.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

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

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

Why was the data set created?

Data were produced to tie the point clouds presented in this data release to lidar for future use.

How was the data set created?

  1. From what previous works were the data drawn?
    2018 lidar (source 1 of 1)
    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: 2024 (process 1 of 1)
    The SGCPs were chosen by looking at the lidar, the dense point clouds, and the imagery. All points that could be located on all data sources and were part of the built environment (and therefore considered to be more stable than the natural environment in this location) were included. The coordinates and elevation of the markers were exported from the lidar. Data sources used in this process:
    • 2018 lidar
  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:

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?
    The horizontal accuracy of these locations is equal to the horizontal accuracy of the lidar, which is not reported
  3. How accurate are the heights or depths?
    The vertical accuracy of these locations is equal to the vertical accuracy of the lidar, which is 10 cm
  4. Where are the gaps in the data? What is missing?
    Dataset 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?
    No formal logical accuracy tests were conducted.

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. This information is not intended for navigation purposes.
  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? The SGCP data are available in a comma-delimited text format.
  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?
  5. What hardware or software do I need in order to use the data set?
    The downloadable data file is available in comma-separated values (CSV) spreadsheet format. Text editing software can be used to open the file, as well as spreadsheet programs, such as Microsoft Excel.

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

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_SGCP_locations_metadata.faq.html>
Generated by mp version 2.9.51 on Tue Sep 9 17:04:02 2025