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 Sodus Bay, 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 Sodus Bay, 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), 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 Sodus Bay, 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 position information derived using surveying techniques, and are used in post-processing to improve the quality of the positioning in the final photogrammetric products.
  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 Sodus Bay, New York in July 2017: data release DOI:10.5066/P9XQYCD0, 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 Sodus Bay, New York, July 12 to 14, 2017.: data release DOI:10.5066/P9XQYCD0, 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., Sturdivant, E.J., 2018, Aerial imagery and photogrammetric products from unmanned aerial systems (UAS) flights over the Lake Ontario shoreline at Sodus Bay, New York, July 12 to 14, 2017: U.S. Geological Survey data release, https://doi.org/10.5066/P9XQYCD0.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -76.98639266
    East_Bounding_Coordinate: -76.93922626
    North_Bounding_Coordinate: 43.27609807
    South_Bounding_Coordinate: 43.26603719
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5b1ee15fe4b092d965254a5c/?name=2017042FA_SodusBay_GCPs_browse.jpg (JPEG)
    Browse image of the locations of the ground control points (red) and transect locations (yellow).
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 12-Jul-2017
    Ending_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 (308)
    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 (targets) and transect point locations
    target points and transect points 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:4792244.349
    Maximum:4793301.629
    Units:meters
    EASTING
    Easting coordinate in UTM Zone 18 meters, NAD83 (2011) (Source: U.S. Geological Survey)
    Range of values
    Minimum:338811.0277
    Maximum:342644.3948
    Units:meters
    ELEVATION
    Orthometric elevation relative to NAVD88 (geoid12a) (Source: U.S. Geological Survey)
    Range of values
    Minimum:75.7273
    Maximum:106.7299
    Units:meters
    ORIGINAL_ID
    Target or transect identifier (name) provided by the surveyor to differentiate between targets and transects, to flag misidentified targets, and to make comments similar to field notes (Source: U.S. Geological Survey) character set used to identify target name and distinguish from transect
    DATE_Collected
    Date of point collection in m/dd/yy format (Source: U.S. Geological Survey) character set to represent calendar date of collection
    Description
    simple descriptor used to distinguish between ground control points (TARGET) and transect points (TRANS) (Source: U.S. Geological Survey) character set
    Entity_and_Attribute_Overview:
    The text file 2017042FA_SodusBay_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 ground control points and transect points. The text contains one header record, and 308 data records with nine columns of comma-separated values.
    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 the ground control points (or targets) was to constrain the photogrammetric products constructed from the aerial images taken at Sodus Bay, 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.

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)
    Fifty-seven ground control points, and 251 transect points, are listed in the CSV file 2017042FA_SodusBay_GCPs.csv. All locations were collected by the USGS field crew over three days of GPS data collection at Sodus Bay, transect points were only collected on the first two days. The targets were moved to accommodate changing data acquisition locations over the two day period. 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. The transects were acquired typically while traversing between target locations. Transects are utilized after photogrammetric processing to assess positional accuracy of the products. 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 established over a temporary benchmark. 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. Ground control point measurements were converted to NAD83(2011) UTM zone 18N meters, NAVD88 (Geoid 12b) as the data were collected. 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 57 targets and 251 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 251 transect points collected within the study area are used to ground truth the 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: 10-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 Sodus Bay, 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 three days. Coordinates in NAD83(2011) UTM zone 18N (EPSG::6347), elevation NAVD88 (geoid 12b) for the reference point are: Northing (m) 4798402.548 (+/-0.0085), Easting (m) 280485.392 (+/-0.006), Orthometric elevation (m) 76.329 (+/-0.017). The uncertainties in parentheses represent peak-to-peak values. 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 1.5 cm (horizontal) and 0.5 cm (vertical). The trasect accuracy is likely less, but was not independently assessed. Transects are used to evaluate the accuracy of the photogrammetry products. Combined with the uncertainty in OPUS fixes for the RTK-GPS base stations, the overall accuracy of the ground control point locations is 1.76 cm (horizontal) and 0.54 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. (see Horizontal_Positional_Accuracy_Report for a complete description of the survey methods). The estimated the 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 1.5 cm (horizontal) and 0.5 cm (vertical). The trasect accuracy is likely less, but was not independently assessed. Transects are used to evaluate the accuracy of the photogrammetry products. Combined with the uncertainty in OPUS fixes for the RTK-GPS base stations, the overall accuracy of the ground control point locations is 1.76 cm (horizontal) and 0.54 cm (vertical).
  4. Where are the gaps in the data? What is missing?
    Locations for all 57 of the ground control points and 251 transect points collected in the Sodus Bay 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 57 ground control points, including commercial targets and plywood targets, as well as 251 transect points. 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), where the “P” indicates plywood target and “T” is a commercial target; each transect (consisting of several GPS fixes along a survey line) has a unique name however the points for that transect are typically named similarly .

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_SodusBay_GCPs.csv, a browse graphic (2017042FA_SodusBay_GCPs_browse.jpg), and associated metadata 2017042FA_SodusBay_GCPs.xml
  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: 10-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_P9XQYCD0/2017042FA_SodusBay_GCPs.faq.html>
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