Ground control point locations for the UAS survey of the Los Padres Reservoir delta, Carmel River valley, CA, 2017-11-01

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Frequently anticipated questions:

What does this data set describe?

Title:
Ground control point locations for the UAS survey of the Los Padres Reservoir delta, Carmel River valley, CA, 2017-11-01
Abstract:
This portion of the data release presents the locations of the temporary ground control points (GCPs) used for the structure-from-motion (SfM) processing of the imagery collected during the unoccupied aerial system (UAS) survey of the Los Padres Reservoir delta, Carmel River valley, CA, 2017-11-01. Twenty temporary ground control points (GCPs) consisting of small square tarps with black-and-white cross patterns were distributed throughout the area to establish survey control. The GCP positions were measured using real-time kinematic (RTK) GPS, using corrections from a GPS base station located on a benchmark designated SFML, located approximately 1 kilometer from the study area. The GCP positions are presented in a comma-delimited text file.
Supplemental_Information:
Additional information about the field activity from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-635-FA
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?
    Logan, Joshua B., and East, Amy E., 20230111, Ground control point locations for the UAS survey of the Los Padres Reservoir delta, Carmel River valley, CA, 2017-11-01: data release DOI:10.5066/P9TO24SR, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Logan, Joshua B., and East, Amy E., 2023, Aerial imagery and structure-from-motion data products from a UAS survey of the Los Padres Reservoir delta, Carmel River valley, CA, 2017-11-01: data release DOI:10.5066/P9J9CHOH, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -121.66731
    East_Bounding_Coordinate: -121.66118
    North_Bounding_Coordinate: 36.38117
    South_Bounding_Coordinate: 36.37326
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/638a95ced34ed907bf79095e?name=F03_20171101T201127Z_RB000585_browse.jpg&allow=openTrue (JPEG)
    Aerial image showing a ground control point used for the UAS survey.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 01-Nov-2017
    Currentness_Reference:
    ground condition at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: comma-delimited text
  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 (21)
    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 0.001
      Ordinates (y-coordinates) are specified to the nearest 0.001
      Planar coordinates are specified in meters
      The horizontal datum used is NAD83 (National Spatial Reference System 2011) (EPSG:1116).
      The ellipsoid used is GRS 1980 (EPSG:7019).
      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 GEOID03
      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)
    pid
    Point ID (Source: producer defined) A unique identification code for the point.
    northing_utmz10_m
    Northing coordinate of data point relative to the NAD83 (National Spatial Reference System 2011) datum, projected in the Universal Transverse Mercator (UTM) Zone 10 North coordinate system, meters (EPSG:6339) (Source: Producer defined)
    Range of values
    Minimum:4026240.496
    Maximum:4027605.687
    Units:meters
    easting_utmz10_m
    Easting coordinate of data point relative to the NAD83 (National Spatial Reference System 2011) datum, projected in the Universal Transverse Mercator (UTM) Zone 10 North coordinate system, meters (EPSG:6339) (Source: Producer defined)
    Range of values
    Minimum:619388.761
    Maximum:619968.032
    Units:meters
    orthometric_ht_navd88_m
    Orthometric height of data point in meters relative to the North American Vertical Datum of 1988 (EPSG:5703), derived using the National Geodetic Survey GEOID03. (Source: Producer defined)
    Range of values
    Minimum:313.960
    Maximum:322.359
    Units:meters

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Joshua B. Logan
    • Amy E. East
  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?

These data are intended to be used to characterize the position, elevation, volume, and morphology of the Los Padres Reservoir delta sediment where the Carmel River enters the reservoir. This assessment of reservoir sediment was made in response to the 2016 Soberanes Fire in the upper Carmel watershed, followed by high flows during water year 2017.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 01-Nov-2017 (process 1 of 2)
    Ground control was established using ground control points (GCPs) consisting of small square tarps with black-and-white cross patterns placed on the ground surface throughout the survey area. The GCP positions were measured using survey-grade GPS receivers operating in real-time kinematic (RTK) mode. For each GCP measurement the GPS receiver was placed on a fixed-height tripod and set to occupy each GCP for a minimum occupation time of one minute. The RTK corrections were referenced to a GPS base station occupying a previously established benchmark designated SFML, located on the Los Padres Reservoir dam approximately 1 kilometer from the survey area. In order to ensure consistency with historic surveys, the previously established position for SFML published in Smith and others, 2009 was used for the real-time surveys. After the survey, the static occupation on SFML was submitted to the National Geodetic Survey (NGS) Online Positioning User Service (OPUS). Person who carried out this activity:
    Joshua Logan
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission Street
    Santa Cruz, CA

    831-460-7519 (voice)
    jlogan@usgs.gov
    Date: 2022 (process 2 of 2)
    A uniform adjustment was applied to the GCPs to shift the positions from the historic reference frame published in Smith and others, 2009 to the updated reference frame observed at the SFML benchmark during the 2017 survey (derived using the National Geodetic Survey (NGS) Online Positioning User Service (OPUS)).
    To ensure consistency with historic data sets, the original published position for the SFML benchmark was used for the RTK GPS base station position. Thus, the GCP positions and original SfM data products were consistent with the historic data presented in Smith and others, 2009. The SFML benchmark position published in that report is (in UTM zone 10 coordinates relative to the NAD83 reference frame): Northing: 4027605.397 Easting: 619388.986 Ortho. Ht. [m, NAVD88]: 322.418 (GEOID03)
    After the 2017-11-01 UAS survey, the 5:40 static GPS occupation on SFML was submitted to NGS OPS which derived the following current-epoch position for SFML: Northing: 4027605.687 Easting: 619388.761 Ortho. Ht. [m, NAVD88]: 322.359 (using GEOID03 separation = -33.047 m)
    Thus, the displacement between the 2009 published SFML position and the 2017-11-01 observed position is: dN: +0.290 meters dE: -0.225 meters dElev.: -0.059 meters
    This magnitude and direction of displacement is similar to those estimated for this location by the National Geodetic Survey Horizontal Time-Dependent Positioning (HTDP), shown below: HTDP OUTPUT, VERSION 3.4.0 DISPLACEMENTS IN METERS RELATIVE TO NAD_83(2011/CORS96/2007) FROM 11-05-2008 TO 11-01-2017 (month-day-year) FROM 2008.847 TO 2017.835 (decimal years) NAME OF SITE: SFML LATITUDE: 36 23 10.23945 N LONGITUDE: 121 40 7.85831 W NORTH: 0.341 meters EAST: -0.241 meters UP: -0.012 meters
    To produce the final data products for this data release, all data were transformed from the historic reference frame into the current-epoch reference frame consistent with the 2017-11-01 observed position for SFML. This transformation was done using a uniform horizontal and vertical adjustment applied to each data set.
    For adjustment of the GCPs, the horizontal and vertical displacements were applied to the northing, easting, and elevation coordinates to shift them into the updated reference frame. Person who carried out this activity:
    Joshua Logan
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission Street
    Santa Cruz, CA

    831-460-7519 (voice)
    jlogan@usgs.gov
  3. What similar or related data should the user be aware of?
    Smith, D.P., Kvitek, R., Aiello, I., Iampietro, P., Quan, C., Paddock, E., Endris, C., and Gomez, K., 2009, Fall 2008 Stage-Volume Relationship for Los Padres Reservoir, Carmel Valley, California: Prepared for the Monterey Peninsula Water Management District.

    Online Links:

    Other_Citation_Details:
    Smith, D.P., Kvitek, R., Aiello, I., Iampietro, P., Quan, C., Paddock, E., Endris, C, and Gomez, K., 2009, Fall 2008 Stage-Volume Relationship for Los Padres Reservoir, Carmel Valley, California: Prepared for the Monterey Peninsula Water Management District. The Watershed Institute, California State University Monterey Bay, Publication no. WI-2009-2, 30 pp.

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?
    GCP positions were measured using a survey-grade dual-frequency GPS receiver operating in real-time kinematic (RTK) mode. The GPS receiver was placed on a fixed-height tripod and set to occupy each GCP for a minimum occupation time of one minute. The RTK corrections were referenced to a GPS base station located on a benchmark designated SFML, located approximately 1 kilometer from the study area. The mean reported horizontal precision of these measurements was 0.008 meters. The reported horizontal peak-to-peak error reported for the base station position from NGS OPUS was 0.015, suggesting a total horizontal accuracy of about 0.020 meters. Uncertainty in the horizontal positions associated with tripod centering, antenna height measurement errors, and errors from the weight of the rover tripod settling onto the GCP tarp during data collection, and possible subsequent rebound of the center of the tarp after removal is unknown.
  3. How accurate are the heights or depths?
    GCP positions were measured using a survey-grade dual-frequency GPS receiver operating in real-time kinematic (RTK) mode. The GPS receiver was placed on a fixed-height tripod and set to occupy each GCP for a minimum occupation time of one minute. The RTK corrections were referenced to a GPS base station located on a benchmark designated SFML, located approximately 1 kilometer from the study area. The mean reported vertical precision of these measurements was 0.012 meters. The reported vertical peak-to-peak error reported for the base station position from NGS OPUS was 0.039 meters, suggesting a total vertical accuracy of about 0.041 meters. Uncertainty in the vertical positions associated with the weight of the tripod settling onto the GCP tarp during data collection, and possible subsequent vertical rebound of the center of the tarp after removal is unknown.
  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 None
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 - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO
    United States

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? The GCP locations 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: 11-Jan-2023
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/ScienceBase/DR_P9J9CHOH/LosPadresReservoir_2017-11-01_GCP_positions_metadata.faq.html>
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