Ground control point locations associated with images collected during unmanned aerial systems (UAS) flights over Coast Guard Beach, Nauset Spit, Nauset Inlet, and Nauset Marsh, Cape Cod National Seashore, Eastham, Massachusetts on 1 March 2016 (Text file and photos)

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Frequently anticipated questions:

What does this data set describe?

Title:
Ground control point locations associated with images collected during unmanned aerial systems (UAS) flights over Coast Guard Beach, Nauset Spit, Nauset Inlet, and Nauset Marsh, Cape Cod National Seashore, Eastham, Massachusetts on 1 March 2016 (Text file and photos)
Abstract:
This dataset documents the locations of ground control points associated with images obtained from unmanned aerial systems (UAS) flown in the Cape Cod National Seashore. Most of the ground control points were temporary targets placed by the U.S. Geological Survey field crew, but four were man-made features already in place, and two were points selected a posteriori from preliminary orthophotomosaics. Photographs of the four in-place features are included in this dataset, as are images showing the location of the two a posteriori points at two zoom levels. The locations of these ground control points can be used to constrain photogrammetric reconstructions based on the aerial imagery. The overall objective of the fieldwork was to evaluate the quality and cost of mapping from UAS images. Low-altitude (approximately 120 meters above ground level) digital images were obtained from cameras in a fixed-wing UAS flown from the lawn adjacent to the Coast Guard Beach parking lot on 1 March, 2016. All activities were conducted according to Federal Aviation Administration regulations and under a National Park Service Scientific Research and Collecting Permit, study number CACO-00285, permit number CACO-2016-SCI-003.
  1. How might this data set be cited?
    U.S. Geological Survey, 2016, Ground control point locations associated with images collected during unmanned aerial systems (UAS) flights over Coast Guard Beach, Nauset Spit, Nauset Inlet, and Nauset Marsh, Cape Cod National Seashore, Eastham, Massachusetts on 1 March 2016 (Text file and photos): data release DOI:10.5066/F7CN721H, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Sherwood, Christopher R., 2016, Low-altitude aerial imagery and related field observations associated with unmanned aerial systems (UAS) flights over Coast Guard Beach, Nauset Spit, Nauset Inlet, and Nauset Marsh, Cape Cod National Seashore, Eastham, Massachusetts on 1 March 2016: data release DOI:10.5066/F7CN721H, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -69.9527
    East_Bounding_Coordinate: -69.9391
    North_Bounding_Coordinate: 41.8478
    South_Bounding_Coordinate: 41.8255
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/57a0b1a6e4b060ce18fbf331?name=CACO_ground_control_points_map_20160301.jpg (JPEG)
    Map of ground control point locations.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 01-Mar-2016
    Currentness_Reference:
    ground condition temporary markers and permanent infrastucture
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form:
    raster digital data 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: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.00000
      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 North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257.
      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?
    Entity_and_Attribute_Overview:
    The text file CACO_ground_control_points_20160301.txt contains two header lines (preceded by hash # characters) and 32 more lines with four columns of comma-separated values. The first header line is the well-known-text (WKT) description of the projection. The second line contains column headings. The columns contain, in order, the name (or label), easting, northing, and elevation. Easting and Northing are UTM Zone 19 North (meters) in the NAD83(2011) coordinate system, the elevation is NAVD88 in meters.
    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)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Christopher R. Sherwood
    Research Oceanographer
    384 Woods Hole Road
    Woods Hole, Massachusetts

    508-548-8700 x2269 (voice)
    508-457-2310 (FAX)
    csherwood@usgs.gov

Why was the data set created?

The objective of obtaining these ground control points was to constrain the photogrammetric products constructed from the aerial images.

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: 12-Mar-2016 (process 1 of 3)
    Thirty-two ground control points are listed in the file CACO_ground_control_points_20160301.txt. Most (28) were targets placed by the USGS field crew but four were man-made features already in place. Of these, one target (B1) was removed and two targets (P6 and T2) were moved between flight 1 and flight 2 in advance of the rising tide. The labels associated with locations of moved targets are appended with _MOVED. Two additional locations without targets (designated fake1 and fake2) were used to improve photogrammetric results in the western marsh portion of the survey area. Placed targets included commercial targets (4 ft x 4 ft x 4-mil thick PVC plastic sheets with black and white diamond patterns and grommets in corners; Berntsen International, Inc. product number AT48IC-STK), plywood targets (2 ft x 2 ft x 1/2-inch thick plywood boards painted with black and white squares), and black plastic trash bags. The commercial targets were designated Tnn and the plywood targets were designated Pnn, where nn is the target number. The trash bags were designated Bxx or BNxx, where xx is the order in which they were deployed. In-place features included BE, BW, FLAGSTONE, and MAN-SW. Photos of these features are included so that they can be identified in the aerial images. Also included are images showing the location of the two points without targets (fake1 and fake2). Horizontal coordinates for these points were picked from a preliminary version of an orthophoto; vertical coordinates were determined from LiDAR data in the 2013-2014 U.S. Geological Survey CMGP LiDAR: Post Sandy (MA, NH, RI) https://coast.noaa.gov/dataviewer/index.html?action=advsearch&qType=in&qFld=ID&qVal=4914. Two differential GPS (Global Positioning System) rover instruments were used by field crews to map targets for ground control points. One was a Spectra Precision model SP80 GNSS (Global Navigation Satellite System) receiver linked via Bluetooth to a data collector (Carlson CHC LT30 Handheld Terminal running Carlson SurvCE v. 4.06 software under Windows Mobile v. 6.1 Professional operating system). This instrument was operated by Sandy Brosnahan. The second rover was a Spectra Precision model ProMark 800 GNSS receiver linked to a similar data collector, operated by Barry Irwin. Both rover antennas were mounted on 2-m survey rods with bubble levels and 5-cm (2-inch) sand feet. The rovers received differential GPS corrections in real time from a base station (described below). The rovers were used to map three reference points established near the base station at the beginning and end of the day. The average absolute deviation largest vertical difference measured was +0.03 m. A differential GPS base station was established over a temporary benchmark on the lawn of the NEED building at Coast Guard Beach. The base station was a Spectra model SP80 GNSS receiver with UHF radio and external antenna mounted on a separate tripod. The antenna height was 2.25 m. The coordinates of the reference point (named CGB_OPUS) were determined from an ultra-rapid precise orbit On-line Positioning User Service (OPUS) solution based on GPS data from a five-hour occupation on January 11, 2016. Coordinates in NAD83 2010(2011) UTM Zone 19 North, elevation NAVD88 (geoid 12a) for the reference point are: Northing (m) 4632792.698 (+/-0.002), Easting (m) 421296.521 (+/-0.003), Orthometric elevation (m) 12.880 (+/-0.012). The uncertainties in parentheses represent peak-to-peak values. Ground control point measurements were converted to NAD83 2010(2011), UTM Zone 19 North (meters) NAVD88 (Geoid 12a) as the data were collected. The measurements were exported from the data collector in a text file that was edited to isolate the ground control points and remove extraneous columns (CACO_ground_control_points_20160301.txt). Person who carried out this activity:
    U.S. Geological Survey
    Attn: Christopher R. Sherwood
    Research Oceanographer
    384 Woods Hole Road
    Woods Hole, Massachusetts

    508-548-8700 x2269 (voice)
    508-457-2310 (FAX)
    csherwood@usgs.gov
    Data sources used in this process:
    • None
    Data sources produced in this process:
    • Ground control points
    Date: 20-Jul-2018 (process 2 of 3)
    USGS Thesaurus keywords added to the keyword section. 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
    Date: 07-Aug-2020 (process 3 of 3)
    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?
    Horizontal positions were determined with one of two GNSS rovers receiving real-time differential corrections from a GNSS base station established over a temporary benchmark on the lawn of the NEED building at Coast Guard Beach. The base station was a Spectra model SP80 GNSS receiver with UHF radio and external antenna mounted on a separate tripod. The antenna height was 2.25 m. The coordinates of the reference point (named CGB_OPUS) were determined from an ultra-rapid precise orbit On-line Positioning User Service (OPUS) solution based on GPS data from a five-hour occupation on January 11, 2016. Coordinates in NAD83 2010(2011) UTM Zone 19, elevation NAVD88 (geoid 12a) for the reference point are: Northing (m) 4632792.698 (+/-0.002), Easting (m) 421296.521 (+/-0.003), Orthometric elevation (m) 12.880 (+/-0.012). The uncertainties in parentheses represent peak-to-peak values. One of the rovers was a Spectra Precision model SP80 GNSS receiver linked via Bluetooth to a data collector (Carlson CHC LT30 Handheld Terminal running Carlson SurvCE v. 4.06 software under Windows Mobile v. 6.1 Professional operating system). This instrument was operated by Sandy Brosnahan. The second rover was a Spectra Precision model ProMark 800 GNSS receiver linked to a similar data collector, operated by Barry Irwin. Both rover antennas were mounted on 2-m survey rods with bubble levels and 5-cm (2-inch) sand feet. The instruments were used to stake three reference points established near the base station at the beginning and end of the day. The average absolute deviation largest horizontal or vertical difference measured was +0.03 m. Conversions from satellite coordinates to NAD83(2011) UTM Zone 19 North and NAVD88 were made by Carlson SurvCE software in the data collector.
  3. How accurate are the heights or depths?
    Vertical positions were determined with one of two GNSS rovers receiving real-time differential corrections from a GNSS base station established over a temporary benchmark on the lawn of the NEED building at Coast Guard Beach (see Horizontal_Positional_Accuracy_Report for a complete description of the survey methods). The instruments were used to stake three reference points established near the base station at the beginning and end of the day. The average absolute deviation largest horizontal or vertical difference measured was +0.03 m. Conversions from satellite coordinates to NAD83(2011) UTM Zone 19 and NAVD88 were made by Carlson SurvCE software in the data collector.
  4. Where are the gaps in the data? What is missing?
    Locations of all 32 of the ground control points are listed in the text file CACO_ground_control_points_20160301.txt. Temporary targets are labeled as Bn, Pn, or Tn in the .txt file. One target (B1) was removed and two targets (P6 and T2) were moved between flight 1 and flight 2 in advance of the rising tide. The temporary targets are clearly visible in the aerial images, so ground photos of these targets are not included. In-place features included with labels BE, BW, FLAGSTONE, and MAN-SW. Ground photos of these features are included so that they can be identified in the aerial images. Also included are the locations of two additional points (labelled fake1 and fake2) that were used to constrain photogrammetry in western portion of Nauset Marsh, where no GCPs were deployed. These points were established by picking flat but distinctive locations in the orthophotomosaic and determining their elevations from the 2013 USGS Lidar data. Images showing the location of these points in the orthophotomosaic are included at two zoom levels.
  5. How consistent are the relationships among the observations, including topology?
    The text file CACO_ground_control_points_20160301.txt lists the locations (coordinates in UTM Zone 19 North meters) of all 32 ground control points, including in-place features, commercial targets, plywood targets, and black plastic trash bags, as well as two points established by picking flat but distinctive locations in the orthophotomosaic. The text contains two header lines (preceded by hash # characters) and 32 more lines with four columns of comma-separated values. The columns contain, in order, the name, easting, northing, and elevation. Easting and Northing are UTM Zone 19 North (meters) in the NAD83(2011) coordinate system. Elevation is in meters referenced to NAVD88. Targets with "MOVED" in the name were moved between flight 1 and flight 2.

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 zip file contains the text file CACO_ground_control_points_20160301.txt, six portable network graphics (PNG) files with images of in-place ground control points, four PNG files with images of the two a posteriori points, and one JPEG file with a map of the study area with markers indicating locations of the ground control points. FGDC CSDGM metadata is also included in XML and HTML formats.
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, nor the USGS, 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 .txt files are plain text with comma-separated-values. They can read with most editors and spreadsheet programs. The .png files are raster digital images and can be read with most image viewing software.

Who wrote the metadata?

Dates:
Last modified: 07-Aug-2020
Metadata author:
U.S. Geological Survey
Attn: Christopher R. Sherwood
Research Oceanographer
384 Woods Hole Road
Woods Hole, Massachusetts

508-548-8700 x2269 (voice)
508-457-2310 (FAX)
csherwood@usgs.gov
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_F7CN721H/CACO_UAS_GCPs.faq.html>
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