Ground control point and transect locations associated with images collected during unmanned aerial systems (UAS) flights over The Lake Ontario shoreline in the vicinity of Chimney Bluffs, New York in July 2017

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Frequently anticipated questions:

What does this data set describe?

Title:
Ground control point and transect locations associated with images collected during unmanned aerial systems (UAS) flights over The Lake Ontario shoreline in the vicinity of Chimney Bluffs, New York in July 2017
Abstract:
Low-altitude (80-100 meters above ground level) digital images were obtained from a camera mounted on a 3DR Solo quadcopter, a small unmanned aerial system (UAS), in three locations along the Lake Ontario shoreline in New York during July 2017. These data were collected to document and monitor effects of high lake levels, including shoreline erosion, inundation, and property damage in the vicinity of Chimney Bluffs State Park, New York. This data release includes images tagged with locations determined from the UAS GPS; tables with updated estimates of camera positions and attitudes based on the photogrammetric reconstruction; tables listing locations of the base stations, ground control points, and transect points; geolocated, RGB-colored point clouds; orthomosaic images; and digital elevation models for each of the survey regions. Collection of these data was supported by the Federal Emergency Management Agency, the State of New York Departments of State and Environmental Conservation, and the USGS Coastal and Marine Geology Program and was conducted under USGS field activity number 2017-042-FA.
Supplemental_Information:
For more information about this field activity, see https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-042-FA. Photogrammetric processing using ground control points produces estimates of camera location and attitude (roll, pitch, and yaw) with much higher accuracies than can be provided by a GPS attached to the UAS. These tables contain ground control points and transect points, derived using surveying techniques, and are used in post-processing to improve the quality of the positioning in the final photogrammetric products, and to verify the accuracy and precision of the photogrammetric products, respectively.
  1. How might this data set be cited?
    U.S. Geological Survey, 2018, Ground control point and transect locations associated with images collected during unmanned aerial systems (UAS) flights over The Lake Ontario shoreline in the vicinity of Chimney Bluffs, New York in July 2017: data release DOI:10.5066/P9W81QEZ, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Sherwood, Christopher R., Brosnahan, Sandra M., Ackerman, Seth D., Borden, Jonathan, Montgomery, Ellyn T., Pendleton, Elizabeth A., and Sturdivant, Emily J., 2018, Aerial imagery and photogrammetric products from unmanned aerial systems (UAS) flights over the Lake Ontario shoreline at Chimney Bluffs, New York, July 14, 2017: data release DOI:10.5066/P9W81QEZ, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Sherwood, C.R., Brosnahan, S.M., Ackerman, S.D., Borden, Jonathan, Montgomery, E.T., Pendleton, E.A., and Sturdivant, E.J., 2018, Aerial imagery and photogrammetric products from unmanned aerial systems (UAS) flights over the Lake Ontario shoreline at Chimney Bluffs, New York, July 14, 2017: U.S. Geological Survey data release, https://doi.org/10.5066/P9W81QEZ.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -76.912025
    East_Bounding_Coordinate: -76.906199
    North_Bounding_Coordinate: 43.290785
    South_Bounding_Coordinate: 43.287241
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5b28643de4b0592076260e53/?name=2017042FA_ChimneyBluffs_GCPs_browse.jpg (JPEG)
    Browse image of the ground control point locations
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 14-Jul-2017
    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?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (33)
    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: -75.00000
      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 0.0001
      Ordinates (y-coordinates) are specified to the nearest 0.0001
      Planar coordinates are specified in meters
      The horizontal datum used is North American Datum of 1983 (2011).
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      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 (NAVD88)
      Altitude_Resolution: 0.0001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    Ground control points and transect point locations
    Target points and transect points were collected using surveying techniques. These tables are used in post-processing to improve the quality of the positioning in the final photogrammetric products (ground control points) and in assessing the vertical accuracy of the final products (transects) (Source: U.S. Geological Survey)
    Northing
    Northing coordinate in UTM Zone 18 meters, NAD83 (2011) (Source: U.S. Geological Survey)
    Range of values
    Minimum:4794488.274
    Maximum:4794871.037
    Units:meters
    Easting
    Easting coordinate in UTM Zone 18 meters, NAD83 (2011) (Source: U.S. Geological Survey)
    Range of values
    Minimum:344880.184
    Maximum:345361.8026
    Units:meters
    Elevation
    Orthometric elevation relative to NAVD88 (geoid12b) (Source: U.S. Geological Survey)
    Range of values
    Minimum:73.7739
    Maximum:120.6586
    Units:meters
    ORIGINAL_ID
    Target or transect identifier (name) provided by the surveyor to differentiate between targets and transects, and to label targets (Source: U.S. Geological Survey) character set used to identify target name and distinguish from transect
    DATE_Collected
    Date of point collection in YYYYMMDD format (Source: U.S. Geological Survey) character set to represent calendar date of collection
    Entity_and_Attribute_Overview:
    The text file 2017042FA_ChimneyBluffs_GCPs.csv lists the locations (coordinates in NAD83(2011) UTM zone 18N (EPSG::6347) for the horizontal, and NAVD88, GEOID 12b, for the vertical, meters) of all 17 ground control points, and 16 transect points. The text contains one header record, and 33 data records with five columns of comma-separated values. The columns contain, in order, northing, easting, elevation, ID, and date collected.
    Entity_and_Attribute_Detail_Citation: USGS Field Activity 2017-042-FA

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: Sandra Brosnahan
    Physical Scientist
    384 Woods Hole Road
    Woods Hole, Massachusetts

    508-548-8700 x2265 (voice)
    508-457-2310 (FAX)
    sbrosnahan@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 taken at Chimney Bluffs, by providing survey-quality ground validation, which far exceeds the accuracy that can be provided from the photo geolocations alone. Transect points are used to validate the final accuracy of the products, and ground control points are used to geolocate the products as accurately as possible.

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: Jul-2017 (process 1 of 3)
    Seventeen ground control points, and 16 transect points, are listed in the CSV file 2017042FA_ChimneyBluffs_GCPs.csv. All locations were collected by the USGS field crew over 1 day of GPS data collection at Chimney Bluffs. 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). The commercial targets were designated Tnn and the plywood targets were designated Pnn, where nn is the one or two digit target number. Transet points were not used in the photogrammetry processing but are included in the GCP file as indicated by "TRANS". Other in-place objects that were surveyed may have other non-conforming designations such as "H" or "ORANGEXROCK-D" in the ORIGINAL_ID field. Two differential GPS (Global Positioning System) rover instruments were used by field crews to map targets for ground control points, 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). Both rover antennas were mounted on 2-m survey rods with bubble levels and 5-cm (2-inch) sand feet. Positions were determined with two GNSS rovers receiving real-time differential corrections from a GNSS base station. Ground control point measurements were transformed to NAD83(2011) UTM zone 18N meters, NAVD88 (Geoid 12b) as the data were collected within the SurvCE software. Person who carried out this activity:
    Sandy Brosnahan
    U.S. Geological Survey
    physical scientist
    U.S. Geological Survey
    Woods Hole, MA

    508-548-8700 x2265 (voice)
    508-457-2310 (FAX)
    sbrosnahan@usgs.gov
    Date: 22-Aug-2017 (process 2 of 3)
    The 17 targets and 16 transect measurements were exported from the data collectors as text file in the RW5 format and then processed (referenced to the base opus rapid static solution) and exported to comma-separated values (CSV) files using the Carlson Report Generator for a SurvCE RW5 Report (https://www.carlsonemea.com/cwa/report). The individual datasets were combined and manually edited to filter by transect point or ground control point and extraneous columns were removed. The target data are used as an input to the Agisoft Photoscan software to control the data horizontally and vertically. The transect points collected within the study area are used to independent of the photogrammetry software to ground truth the accuracy and precision of processed data products (Point Cloud, DEM and Orthomosaic) created in Agisoft Photoscan. Person who carried out this activity:
    Sandy Brosnahan
    U.S. Geological Survey
    physical scientist
    U.S. Geological Survey
    Woods Hole, MA

    508-548-8700 x2265 (voice)
    508-457-2310 (FAX)
    sbrosnahan@usgs.gov
    Date: 06-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?
    Three Spectra Precision SP80 GNSS receivers were used to collect the ground control points and transect coordinates. Two of the units functioned as "rovers" and the third was a stationary base broadcasting a signal from a static point, later used to correct all rover coordinates. Overall measured horizontal accuracy based on re-occupation of the same location was 1.5 cm and vertical accuracy was 0.5 cm.
  2. How accurate are the geographic locations?
    Horizontal positions were determined with two GNSS rovers receiving real-time differential corrections from a GNSS base station established over a temporary benchmark in Chimney Bluffs NY. 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 were determined from an ultra-rapid precise orbit On-line Positioning User Service (OPUS) solution based on GPS data from an average over 1 day, on July 14th, 2017. Both of the rovers were Spectra Precision model SP80 GNSS receivers 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). Both rover antennas were mounted on 2-m survey rods with bubble levels and 5-cm (2-inch) sand feet. The estimated uncertainty of target locations was determined by examining differences for repeat measurements of the same target, lumping measurements for all real-time kinematic (RTK) rovers. The mean of the standard deviations for repeat measurements was 5.3 cm (horizontal) and 0.1 cm (vertical). Combined with the uncertainty in OPUS fixes for the RTK-GPS base stations, the overall accuracy of the ground control point locations is 5.8 cm (horizontal) and 0.88 cm (vertical). Conversions from satellite coordinates to NAD83(2011) UTM zone 18N (EPSG::6347) 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 the GNSS rovers receiving real-time differential corrections from a GNSS base station established over a temporary benchmark, in Chimney Bluffs NY. (see Horizontal_Positional_Accuracy_Report for a complete description of the survey methods). The estimated uncertainty of target locations was determined by examining differences for repeat measurements of the same target, lumping measurements for all RTK rovers. The mean of the standard deviations for repeat measurements was 5.3 cm (horizontal) and 0.1 cm (vertical). Combined with the uncertainty in OPUS fixes for the RTK-GPS base stations, the overall accuracy of the ground control point locations is 5.8 cm (horizontal) and 0.88 cm (vertical).
  4. Where are the gaps in the data? What is missing?
    Locations for all 17 of the ground control points and 16 transect points collected in the Chimney Bluffs study area are listed in the CSV text file.
  5. How consistent are the relationships among the observations, including topology?
    The CSV file lists the locations (coordinates in NAD83(2011) UTM zone 18N (EPSG::6347) for the horizontal, and NAVD88 meters, GEOID 12b, for the vertical) for all 17 ground control points, including commercial targets and plywood targets, as well as 16 transect points. The text contains one header record, and 33 data records with five columns of comma-separated values. The columns contain, in order, northing, easting, elevation, Origninal_ID, and date collected. Northing and Easting are in the NAD83(2011) UTM zone 18N (EPSG::6347) coordinate system. Elevation is in meters referenced to NAVD88. The ground control points and transect points were collected at the same time and with the same equipment. The target names (ORIGINAL_ID) are uniquely named (e.g P1, T20, T31); each transect (consisting of several GPS fixes along a survey line) has a "TRANS" entry; any record with an entry for the ORIGINAL_ID field that is NOT "TRANS" is a target.

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 (USGS) as the source of this information.
  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? This data release contains the CSV file 2017042FA_ChimneyBluffs_GCPs.csv and associated metadata 2017042FA_ChimneyBluffs_GCPs.xml and a browse graphic (2017042FA_ChimneyBluffs_GCPs_browse.jpg).
  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 U.S. Geological Survey 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 CSV file is plain text with comma separated values. It can be read with most text editors or spreadsheet programs.

Who wrote the metadata?

Dates:
Last modified: 06-Aug-2020
Metadata author:
Sandra Brosnahan
U.S. Geological Survey
Physical Scientist
U.S. Geological Survey
Woods Hole, MA

508-548-8700 x2265 (voice)
508-457-2310 (FAX)
sbrosnahan@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P9W81QEZ/2017042FA_ChimneyBluffs_GCPs.faq.html>
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