Positions of temporary targets used as ground control points associated with UAS flights over Black Beach, Falmouth, Massachusetts on 18 March 2016 (text file)

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Frequently anticipated questions:

What does this data set describe?

Title:
Positions of temporary targets used as ground control points associated with UAS flights over Black Beach, Falmouth, Massachusetts on 18 March 2016 (text file)
Abstract:
Imagery acquired with unmanned aerial systems (UAS) and coupled with structure from motion (SfM) photogrammetry can produce high-resolution topographic and visual reflectance datasets that rival or exceed lidar and orthoimagery. These new techniques are particularly useful for data collection of coastal systems, which requires high temporal and spatial resolution datasets. The U.S. Geological Survey worked in collaboration with members of the Marine Biological Laboratory and Woods Hole Analytics at Black Beach, in Falmouth, Massachusetts to explore scientific research demands on UAS technology for topographic and habitat mapping applications. This project explored the application of consumer-grade UAS platforms as a cost-effective alternative to lidar and aerial/satellite imagery to support coastal studies requiring high-resolution elevation or remote sensing data. A small UAS was used to capture low-altitude photographs and GPS devices were used to survey reference points. These data were processed in an SfM workflow to create an elevation point cloud, an orthomosaic image, and a digital elevation model.
Supplemental_Information:
For more information regarding field activity 2016-010-FA, see https://cmgds.marine.usgs.gov/fan_info.php?fan=2016-010-FA.
  1. How might this data set be cited?
    Sturdivant, Emily J., Lentz, Erika E., Thieler, E. Robert, Remsen, David P., and Miner, Simon, 2017, Positions of temporary targets used as ground control points associated with UAS flights over Black Beach, Falmouth, Massachusetts on 18 March 2016 (text file): data release DOI:10.5066/F7KW5F04, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details:
    The first link is to the publication landing page. The second link is to the page containing the data.
    This is part of the following larger work.

    Sturdivant, Emily J., Thieler, E. Robert, Lentz, Erika E., Remsen, David P., and Miner, Simon, 2017, Topographic, imagery, and raw data associated with unmanned aerial systems (UAS) flights over Black Beach, Falmouth, Massachusetts on 18 March 2016: data release DOI:10.5066/F7KW5F04, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Sturdivant, E.J., Thieler, E.R., Lentz, E.E., Remsen, D.P., and Miner, Simon, 2017, Topographic, imagery, and raw data associated with unmanned aerial systems (UAS) flights over Black Beach, Falmouth, Massachusetts on 18 March 2016: U.S. Geological Survey data release, https://doi.org/10.5066/F7KW5F04.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.643
    East_Bounding_Coordinate: -70.641
    North_Bounding_Coordinate: 41.586
    South_Bounding_Coordinate: 41.583
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/59b00e00e4b020cdf7d4db31/?name=bb20160318_gcps_browse.png (PNG)
    Map of ground control point locations
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 18-Mar-2016
    Currentness_Reference:
    ground condition temporary markers
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: digital text files
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    2. What coordinate system is used to represent geographic features?
      The map projection used is Universal Transverse Mercator.
      Projection parameters:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -69.00000
      Latitude_of_Projection_Origin: 0.000
      False_Easting: 500000.0000
      False_Northing: 0.0000
      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 World Geodetic System 1984 (WGS 84).
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257224.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988 (NAVD88)
      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?
    bb20160318_gcps.csv
    These files contain positions in the horizontal and vertical plane surveyed at Black Beach to provide independent reference points for accuracy assessment of photogrammetric elevation products. (Source: U.S. Geological Survey)
    Note
    Target identifier. (Source: GPS operator) character set
    Latitude
    Latitude in degrees minutes seconds referenced to WGS 84. (Source: SP80 GNSS receiver)
    Range of values
    Minimum:41 34 59.559114
    Maximum:41 35 11.049408
    Units:degrees minutes seconds
    Resolution:1.0E-6
    Longitude
    Longitude in degrees minutes seconds referenced to WGS 84. (Source: SP80 GNSS receiver)
    Range of values
    Minimum:-70 38 36.578868
    Maximum:-70 38 27.210132
    Units:degrees minutes seconds
    Resolution:1.0E-6
    Elevation
    Ellipsoid elevation in meters referenced to WGS 84 mean sea level. (Source: SP80 GNSS receiver)
    Range of values
    Minimum:-26.6034
    Maximum:-23.7434
    Units:meters
    Resolution:1.0E-4
    Local_N
    Northing in meters referenced to UTM Zone 19 North referenced to WGS 84. (Source: SP80 GNSS receiver)
    Range of values
    Minimum:4604805.531
    Maximum:4605156.798
    Units:meters
    Resolution:1.0E-4
    Local_E
    Easting in meters referenced to UTM Zone 19 North referenced to WGS 84. (Source: SP80 GNSS receiver)
    Range of values
    Minimum:363008.5896
    Maximum:363226.5609
    Units:meters
    Resolution:1.0E-4
    Local_Z
    Elevation referenced to NAVD88. (Source: SP80 GNSS receiver)
    Range of values
    Minimum:0.0212
    Maximum:2.8787
    Units:meters
    Resolution:1.0E-4
    Dev_1
    Horizontal RMS error reported by the GNSS receiver. (Source: SP80 GNSS receiver)
    Range of values
    Minimum:0.008
    Maximum:0.017
    Units:meters
    Resolution:1.0E-4
    Dev_2
    Vertical RMS error reported by the GNSS receiver. (Source: SP80 GNSS receiver)
    Range of values
    Minimum:0.01
    Maximum:0.022
    Units:meters
    Resolution:1.0E-4
    noSV
    number of visible satellites, dilution of precision (DOP), (Source: SP80 GNSS receiver)
    Range of values
    Minimum:14
    Maximum:18
    PDOP
    Positional dilution of precision (DOP) (Source: SP80 GNSS receiver)
    Range of values
    Minimum:0.9
    Maximum:1.6
    Units:meters
    Resolution:1.0E-1
    HDOP
    Horizontal dilution of precision (DOP) (Source: SP80 GNSS receiver)
    Range of values
    Minimum:0.5
    Maximum:0.9
    Units:meters
    Resolution:1.0E-1
    VDOP
    Vertical dilution of precision (DOP) (Source: SP80 GNSS receiver)
    Range of values
    Minimum:0.8
    Maximum:1.4
    Units:meters
    Resolution:1.0E-1
    GPS_TIME
    Date and time in Coordinated Universal Time (UTC) at which the data were recorded in the field in Fri, 18 Mar 2016 HH:MM:SS format. (Source: SP80 GNSS receiver)
    Range of values
    Minimum:Fri, 18 Mar 2016 14:03:41
    Maximum:Fri, 18 Mar 2016 14:52:03
    PhotoScan_ptID
    Point number assigned by PhotoScan to the GCP (Source: Agisoft Photoscan) character set
    Operator
    Surname of crewmember who collected the point. (Source: Sturdivant) character set
    Entity_and_Attribute_Overview:
    The text file contains one header line and 18 additional lines with 16 columns of comma-separated values. The first header line contains column headings.
    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)
    • Emily J. Sturdivant
    • Erika E. Lentz
    • E. Robert Thieler
    • David P. Remsen
    • Simon Miner
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Emily J. Sturdivant
    Geographer
    384 Woods Hole Road
    Woods Hole, Massachusetts

    508-548-8700 x2230 (voice)
    508-457-2310 (FAX)
    esturdivant@usgs.gov

Why was the data set created?

These points were surveyed to provide the horizontal and vertical positions of 18 temporary targets that were used to geo-reference photogrammetric products derived from an aerial image survey at Black Beach on 18 March, 2016.

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: 18-Mar-2016 (process 1 of 2)
    These points correspond to the 18 temporary targets placed in the field by the U.S. Geological Survey field crew and used as ground control points (GCPs) to geo-reference SfM products. Field crews distributed 18 targets evenly around the study area by referring to a pre-created map with suggested placement of GCPs. Targets were commercial 4 ft x 4 ft x 4-mil thick PVC plastic sheets diagonally quartered in alternating black and white triangles (Berntsen International, Inc. product number AT48IC-STK). Each target was labeled with a unique identifying integer.
    Field crews used three differential GNSS (Global Navigation Satellite System) rover instruments to record the horizontal and vertical position of the targets. The rovers received differential GPS corrections in real time from a base station on the Massachusetts Continuously Operating Reference Station Network (MaCORS) for RTK position corrections that yield (x,y,z) data accurate to within 1-3 cm (network: NTRIP RTCM3_MAX). The RTK base station was located in East Falmouth, approximately 9 km from Black Beach. Positions were referenced to WGS 84, UTM Zone 19 North (meters horizontal) and Geoid 12a, NAVD88 (meters vertical) by the MaCORS base station.
    Two rovers were Spectra Precision model SP80 GNSS receivers with antenna SPP91564_2 (radius: 0.0985 m; slant height measure point: 0.028 m; L1 offset: 0.0826 m; L2 offset: 0.0756 m; instrument height: 2.0826 m) and the other, model ProMark GNSS Receiver 800 was operated with antenna ASH802147 (radius: 0.098 m; slant height measure point: 0.04 m; L1 offset: 0.0852 m; L2 offset: 0.0922 m; instrument height: 2.0852 m). Rover antennas were mounted on 2-m survey rods with bubble levels and 5-cm (2-inch) sand feet. The receivers were connected to Carlson CHC LT30 Handheld Terminal running Carlson SurvCE software under Windows Mobile v. 6.1 Professional operating system.
    Rovers were operated by Sandy Brosnahan, Barry Irwin, Jonathan Borden, and E. Robert Thieler to survey the temporary targets and survey elevations around the study area. The SP80 rover operated by Brosnahan was connected by receiver Wifi to a data collector running SurvCE Version 4.06. Brosnahan surveyed Targets 1–10 (twice surveying Target 2) on the western landmass and two south–north transects from the tidal flats to the marsh. The rover operated by Thieler was connected by Data Collector Internet to the data collector running SurvCE Version 4.07. Thieler surveyed targets 11–16 and 19–20. The ProMark 800 was connected by internal GSM to the data collector running SurvCE Version 4.90.44. It was operated by Irwin to survey Targets 1–10 (except for Target 2) and 5 west–east transects from the beach and to the marsh. Positions were only recorded when the solution was fixed.
    The measurements were exported from the data collector in a text file in the RW5 format and then converted to a comma-separated values file using the Carlson Report Generator for a SurvCE RW5 Report (https://www.carlsonemea.com/cwa/report). The three datasets were consolidated into one and then manually divided into two: GCP locations and transect points by referring to the operator-entered label stored in the Note column. The Note column indicates the target number and can be used to match the coordinate to its corresponding target. All points used as GCPs in SfM processing (see bb_20160318_pointcloud.laz metadata in the larger work) are listed in the text file. The following columns were removed because they contained values that were unnecessary or misleading: Point_ID, Cartesian_X, Cartesian_Y, Cartesian_Z, Ant_Hgt_KI, Ant_Hgt_True, Solution, PC DATE STAMP, PC TIME STAMP, and GPS END TIME. The Note column was moved to the first column position. The columns PhotoScan_ptID and Operator were added and populated manually to correspond to the GCP label in the SfM software and the rover operator. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Emily J. Sturdivant
    Geographer
    384 Woods Hole Road
    Woods Hole, Massachusetts

    508-548-8700 x22630 (voice)
    508-457-2310 (FAX)
    esturdivant@usgs.gov
    Date: 07-Aug-2020 (process 2 of 2)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?

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

  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
    A formal accuracy assessment of the horizontal positional information in the data set has not been conducted. Horizontal RMS error is calculated for each point in the column “Dev_1” of the data file. The average HRMS error estimated by the receivers is approximately 0.011 m. The largest horizontal difference measured was 0.017 m. Positions were only recorded when the solution was fixed. Number of visible satellites was always greater than 13 and the geometry of triangulation points was consistently of high quality, indicated by dilution of precision (DOP) values close to 1. Position DOP ranged from 0.9 to 1.1, horizontal DOP from 0.5 to 0.7, and vertical DOP from 0.8 to 0.9.
  3. How accurate are the heights or depths?
    A formal accuracy assessment of the positional information in the data set has not been conducted. Vertical RMS is recorded for each entry in the column “Dev_2” of the data file. The average VRMS estimated by the receivers is approximately 0.014 m. The largest vertical difference measured was 0.018 m. Number of visible satellites was always greater than 13 and the geometry of triangulation points was consistently of high quality, indicated by dilution of precision (DOP) values close to 1. Position DOP ranged from 0.9 to 1.1, horizontal DOP from 0.5 to 0.7, and vertical DOP from 0.8 to 0.9.
  4. Where are the gaps in the data? What is missing?
    The locations of all 18 targets are listed in the text file. In cases where the same target was surveyed multiple times, the surveyed locations were compared and finding that all locations matched, those surveyed by Brosnahan were retained. The Note column indicates the target number. The following columns were removed because they contained values that were unnecessary or misleading: Point_ID, Cartesian_X, Cartesian_Y, Cartesian_Z, Ant_Hgt_KI, Ant_Hgt_True, Solution, PC DATE STAMP, PC TIME STAMP, and GPS END TIME.
  5. How consistent are the relationships among the observations, including topology?
    Coordinates recorded for each entry describe discrete positions in space. A total of 18 targets were placed, each of which had a unique ID between 1 and 20. Targets 1-10 are referred to in the data as TXX, whereas the remaining targets are referred to as gcpXX. Targets 17 and 18 were not placed.

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:
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset.
  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

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? The data include a comma-separated values file of the ground control points and one PNG file with a map of the study area with markers indicating locations of the ground control points. Additionally, the CSDGM FGDC metadata in XML format is included.
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, the USGS, the Marine Biological Laboratory, Woods Hole Analytics, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  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 file is plain text with comma-separated-values. It can be read with most editors and spreadsheet programs.

Who wrote the metadata?

Dates:
Last modified: 19-Nov-2021
Metadata author:
U.S. Geological Survey
Attn: Emily J. Sturdivant
384 Woods Hole Road
Woods Hole, Massachusetts

508-548-8700 x2230 (voice)
508-457-2310 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the metadata contact is no longer with the USGS or the email is otherwise invalid.
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_F7KW5F04/bb20160318_gcps_meta.faq.html>
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