Braddock West camera locations and attitudes for low-altitude aerial images collected during unmanned aerial systems (UAS) flights over of the Lake Ontario shoreline in the vicinity of Braddock Bay, New York in July 2017

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Frequently anticipated questions:


What does this data set describe?

Title:
Braddock West camera locations and attitudes for low-altitude aerial images collected during unmanned aerial systems (UAS) flights over of the Lake Ontario shoreline in the vicinity of Braddock 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), 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 vicinities of Braddock Bay, Sodus Bay, and 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. These tables contain position and attitude estimates derived from photogrammetric post-processing and are considered to have better positional accuracy than the GPS information provided in the EXIF headers in the images in the photo dataset.
  1. How might this data set be cited?
    U.S. Geological Survey, 2018, Braddock West camera locations and attitudes for low-altitude aerial images collected during unmanned aerial systems (UAS) flights over of the Lake Ontario shoreline in the vicinity of Braddock Bay, New York in July 2017: data release DOI:10.5066/F74F1PX3, U.S. Geological Survey, Reston, VA.

    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 Braddock Bay, New York, July 10 to 11, 2017.: data release DOI:10.5066/F74F1PX3, 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 Braddock Bay, New York, July 10 to 11, 2017: U.S. Geological Survey data release, https://doi.org/10.5066/F74F1PX3.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -77.713146
    East_Bounding_Coordinate: -77.701520
    North_Bounding_Coordinate: 43.311624
    South_Bounding_Coordinate: 43.304969
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5a58c991e4b00b291cd6a63d/?name=2017042FA_BraddockWest_CameraLocations_browse.jpg (JPEG)
    Browse image of the camera locations text file
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 10-Jul-2017
    Currentness_Reference:
    ground condition
  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 (1175)
    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 0.001
      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 6378137.000000.
      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
      Altitude_Resolution: 0.000001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    Braddock East camera locations
    These locations have been processed using photogrammetric software and ground control points and are considered more accurate than the GPS coordinates recorded by the UAS-attached GPS and included in the photograph EXIF tags. (Source: U.S. Geological Survey)
    #Label
    Photograph name in standard USGS format (Source: U.S. Geological Survey) character set of photograph name including: survey ID, Camera ID, flight ID, date and time, and original filename to ensure no duplicated filenames
    X/Easting
    Easting coordinate of the camera in UTM Zone 18 meters, NAD83 (EPSG::26918) as determined by the UAS-attached GPS and applied to photo during 'geotagging'. These coordinates were converted from WGS84 to NAD83, upon import to Photoscan, but are otherwise the same as the coordinates in the photo EXIF GPS-tags. (Source: U.S. Geological Survey)
    Range of values
    Minimum:279947.8216
    Maximum:280914.695
    Units:meters
    Y/Northing
    Northing coordinate of the camera in UTM Zone 18 meters, NAD83 (EPSG::26918) as determined by the UAS-attached GPS and applied to photo during 'geotagging'. These coordinates were converted from WGS84 to NAD83, upon import to Photoscan, but are otherwise the same as the coordinates in the photo EXIF GPS-tags. (Source: U.S. Geological Survey)
    Range of values
    Minimum:4798256.913
    Maximum:4798965.5
    Units:meters
    Z/Altitude
    Orthometric height of the camera in NAD83 (EPSG::26918) as determined by the UAS-attached GPS and applied to photo during 'geotagging'. These altitudes were converted from WGS84 (ellipsoidal heights) to NAD83, upon import to Photoscan, but are otherwise the same as the altitudes in the photo EXIF GPS-tags. (Source: U.S. Geological Survey)
    Range of values
    Minimum:70.610
    Maximum:171.5
    Units:meters
    Error_(m)
    total difference (in meters) between the initial coordinates from the UAS GPS log (inclduded in the photograph EXIF GPStags header) and the coordinates estimated from the photogrammetric reconstruction. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:68.295
    Units:meters
    X_error
    X difference (in meters) between the initial Easting coordinates from the UAS GPS log (inclduded in the photograph EXIF GPStags header) and the coordinates estimated from the photogrammetric reconstruction. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-42.577513
    Maximum:36.649155
    Units:meters
    Y_error
    Y difference (in meters) between the initial Northing coordinates from the UAS GPS log (inclduded in the photograph EXIF GPStags header) and the coordinates estimated from the photogrammetric reconstruction. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-53.046004
    Maximum:36.13526
    Units:meters
    Z_error
    Z difference (in meters) between the initial altitude coordinates from the UAS GPS log (inclduded in the photograph EXIF GPStags header) and the coordinates estimated from the photogrammetric reconstruction. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-12.790666
    Maximum:16.589517
    Units:meters
    X_est
    X-coordinate of the camera in UTM Zone 18 meters, NAD83 (EPSG::26918) estimated from the photogrammetric reconstruction using ground control points (Source: U.S. Geological Survey)
    Range of values
    Minimum:279953.9605
    Maximum:280913.7166
    Units:meters
    Y_est
    Y-coordinate of the camera in UTM Zone 18 meters, NAD83 (EPSG::26918) estimated from the photogrammetric reconstruction using ground control points (Source: U.S. Geological Survey)
    Range of values
    Minimum:4798254.599
    Maximum:4798966.82
    Units:meters
    Z_est
    Z-coordinate (altitude) of the camera in meters adjusted to the NAVD88 orthometric heights as estimated from the photogrammetric reconstruction using ground control points (Source: U.S. Geological Survey)
    Range of values
    Minimum:81.938835
    Maximum:183.457731
    Units:meters
    Yaw_est
    estimated (by photogrammetric reconstruction) rotation of the camera relative to the y-axis (Source: U.S. Geological Survey)
    Range of values
    Minimum:5.744054
    Maximum:354.997242
    Units:degrees
    Pitch_est
    estimated (by photogrammetric reconstruction) rotation of the camera relative to the x-axis (Source: U.S. Geological Survey)
    Range of values
    Minimum:-36.492916
    Maximum:27.907664
    Units:degrees
    Roll_est
    estimated (by photogrammetric reconstruction) rotation of the camera relative to the z-axis (Source: U.S. Geological Survey)
    Range of values
    Minimum:-50.472354
    Maximum:26.899018
    Units:degrees
    Entity_and_Attribute_Overview:
    The list of images and camera location information are provided in a CSV text file named 2017042FA_BraddockWest_CameraLocations.csv.
    The text contains one header line denoted with a "#' character, followed by rows of data records; there are 14 columns of data separated by commas. The first header row specifies the column headings for the data, as follows: Label (full name of the image file), X/Easting, Y/Northing, and Z/Altitude (initial horizontal and vertical coordinates from the UAS GPS log), Error_(m), X_error Y_error, Z_error (total distance, and x, y, an z components of the distances (meters) between the initial coordinates from the UAS GPS log and the coordinates estimated from the photogrammetric reconstruction), X_est, Y_est, Z_est (coordinates estimated from the photogrammetric reconstruction), Yaw_est, Pitch_est, Roll_est (camera attitude estimated from the photogrammetric reconstruction).
    The fields X/Easting, Y/Northing, and Z/Altitude are the uncorrected horizontal and vertical values and are therefore reported in this PhotoScan export in the coordinate system and vertical datum of original projection of the BraddockWest project (see process number 2 in the processing steps above). The fields X_est, Y_est, Z_est are in coordinates corrected by the image alignment and photogrammetry process; the X_est and Y_est are in the horizontal datum of the PhotoScan project (NAD83 UTM Zone 18 EPSG::26918) and the Z_est values are referenced to the NAVD88 vertical datum.
    If the image was not successfully aligned in the photogrammetric reconstruction, estimated camera location and attitude are not available, and only the first five columns contain valid data. Missing data for these unused cameras (images) are indicated by "NaN".
    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?

This camera location data provides updated image location information as determined by the Agisoft Photoscan software as a result of processing that included automated image alignment, lens calibration and using independent ground control data. The cameras (or images) noted in this table were imported into the Photoscan software and, if successfully aligned, they were used in the creation of the final photogrammetric products (including point clouds, digital elevation models and orthomosaics). In addition to XYZ location, attitude data estimates (yaw, pitch and roll), and error values from the original photo GPS data are also included.

How was the data set created?

  1. From what previous works were the data drawn?
    geotagged aerial digital images (source 1 of 2)
    U.S. Geological Survey, 2018, Geotagged low-altitude aerial imagery from unmanned aerial systems (UAS) flights over of the Lake Ontario shoreline in the vicinity of Braddock Bay, New York, USA in July 2017: data release DOI:10.5066/F74F1PX3, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: raster digital images
    Source_Contribution:
    The digital images are the raw data used to produce subsequent photogrammetric products.
    text files with ground control point (GCPs) (source 2 of 2)
    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 Braddock Bay, New York, USA in July 2017: data release DOI:10.5066/F74F1PX3, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: text data files
    Source_Contribution:
    The ground control points (GCPs; not transect points -- see metadata for more information) were used to geolocate the photogrammetric products.
  2. How were the data generated, processed, and modified?
    Date: Sep-2017 (process 1 of 3)
    During USGS field activity 2017-042-FA, digital images were taken approximately 80 and 100 m above the ground on July 10 - 14, 2017, with a Ricoh GRII digital camera mounted in a 3DR Solo quadcopter operated by the U.S. Geological Survey. This camera location file, for the Braddock Bay project, was created using a standard processing flow as described in the processing steps below. These camera locations are the product of one of several photogrammetry projects from field activity 2017-042-FA. Two projects incorporated flights over Braddock Bay on July 10 and 11, 2017 (Braddock West, Braddock East); four were used for flights in the vicinity of Sodus Bay on July 12, 13, and 14, 2017 (Lake Bluff / Crescent Bar, Crescent Bar / Charles Point, Sodus North, and Greig Street); and one project incorporated flights over Chimney Bluffs on July 14, 2017.
    For this camera location file, original camera position estimates were determined using Mission Planner software (version 1.3.49). These position estimates are written to the header of JPEG images in a process know as geotagging. Geotagging functionality in Mission Planner is accessed from the main menu by clicking 'control' and 'F', and then choosing 'GeoRef Images' from the menu that pops up. Geotagging requires a telemetry log (created by mission planner during survey flight), photos (collected by the Ricoh camera during flight), and a time offset between camera and GPS if applicable. The updated camera locations also present in this dataset were determined using photogrammetry software (Agisoft Photoscan Professional v. 1.3.2), and differ from the original position estimates due to photogrammetric correction and ground control adjustments. Person who carried out this activity:
    U.S. Geological Survey, Woods Hole Coastal and Marine Science Center
    Attn: Christopher R. Sherwood
    Research Oceanographer
    384 Woods Hole Road
    Woods Hole, Massachusetts
    U.S.A.

    508-548-8700 x2269 (voice)
    508 457 2310 (FAX)
    csherwood@usgs.gov
    Date: 13-Sep-2017 (process 2 of 3)
    The following steps make up the general processing flow for creating digital elevation models from UAS flights:
    1. Geotagged images (see source citation) containing useful imagery from the survey area were imported into Agisoft Photoscan Professional v. 1.3.2 software using the “Add photos…” tool. Photos taken before and immediately after takeoff, photos taken immediately prior to and after landing, and photos with 100% water were not loaded into the project. Project coordinate system is set to EPSG::7660 WGS84 (G1150) geocentric coordinate system.
    2. Using ”Convert”, the coordinate system of the images (called “cameras” in Photoscan) was converted from native latitude/longitude WGS84 (G1150) coordinate system to meters in NAD83/UTM zone 18N (EPSG::26918).
    3. The photos were processed through an initial alignment and optimization procedure using the following settings:
    Alignment - Accuracy: “High”; Pair selection: “Reference”; Key point limit: 80,000; Tie point limit; 0 (unlimited). Adaptive camera model fitting option was selected.
    Optimization - Lens-calibration parameters f, cx, cy, k1, k2, k3, p1, and p2 were included; b1, b2, and higher-order parameters k4, p3, and p4 were not.
    4. The sparse point cloud (also known as tie points; created as a result of photo alignment and optimization) was edited using an iterative error-reduction procedure to filter the data. This was done in several iterations of a process called "Gradual Selection" to first to reduce reconstruction uncertainty (to a unitless value of 10) and then projection accuracy (to a weighted value of 3).
    5. Ground control points were created by first by letting the software automatically detect markers where it finds all of the 4-ft square black/white targets deployed (false targets that are sometimes detected were manually deleted). The automatically-generated marker labels were manually changed to match the names in the survey notes and GCP location files.
    6. "Import markers” was used to load the GCP location file, which assigned coordinates (northing, easting, and elevation in UTM Zone 18 North meters in NAD83 and NAVD88 coordinate systems) from the location file to the detected markers. The locations of auto-detected markers were retained.
    7. Another round of "Gradual Selection" was done to reduce the reprojection error (to a value of 0.3 pixels, unless more than 10% of the points would be removed).
    8. A dense point cloud was then created with the parameters "High" quality and “Aggressive” depth filtering.
    9. A DEM was create with the parameters Source data="Dense Cloud" Interpolation="Enabled" Resolution="0.05"
    10. An orthomosaic was create with the parameters Surface="DEM" Blending mode="Mosaic" Pixel size X="0.025" Pixel size Y="0.025"
    11. The camera locations data (this dataset) was exported in CSV text format (2017-07-10_Braddock_West_CAMERAS.csv) from Photoscan with the following parameters (Items=Cameras, Delimiter=Comma, Columns=[all boxes checked on] with Precision=6). This file was manually edited to remove columns that contained no data for all records and to fill those columns for the photos not successfully aligned with a no-data value of "NaN". Then the file was renamed (2017042FA_BraddockWest_CameraLocations.csv). Person who carried out this activity:
    U.S. Geological Survey, Woods Hole Coastal and Marine Science Center
    Attn: Christopher R. Sherwood
    Research Oceanographer
    384 Woods Hole Road
    Woods Hole, Massachusetts
    U.S.A.

    508-548-8700 x2269 (voice)
    508 457 2310 (FAX)
    csherwood@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 recorded in the UAS flight logs and later applied to the EXIF portion of the images were derived from a mRo GPS (u-Blox Neo-M8N / 3DR SOLO Upgrade), which received signals from GPS and GLONASS satellites, but are otherwise uncorrected. Horizontal locations for the original photo dateset are considered accurate to approximately 3 meters, but may be off by as much as 10 meters. Horizontal camera positions, presented in this dataset, are calculated from photogrammetry and are considered more accurate because the location takes into account the overall reconstruction of the Photoscan project incorporating tie points from adjacent aerial photos and the ground control point data. The estimated camera positions are likely accurate to within 0.2 m.
  3. How accurate are the heights or depths?
    Vertical positions recorded in the UAS flight logs and later applied to the EXIF portion of the images were derived from a mRo GPS (u-Blox Neo-M8N / 3DR SOLO Upgrade), which receives signals from GPS and GLONASS satellites, but is otherwise uncorrected. Vertical locations from the GPS are considered to be less accurate than horizontal positions and may be off by more than 10 meters. Like the horizontal camera positions, the vertical camera positions, presented in this dataset, are calculated from photogrammetry and are considered more accurate because the location takes into account the overall reconstruction of the Photoscan project incorporating tie points from adjacent aerial photos and the ground control point data. The estimated camera positions are likely accurate to within 0.2 m.
  4. Where are the gaps in the data? What is missing?
    Twenty-two UAS flights (f1 - f22) were conducted in Braddock Bay survey areas along the NY Lake Ontario shoreline. Flights 2, 8, 9, 14, and 15 were aborted for reasons including errors in the telemetry log, loss of contact with GPS base station, and poor photo quality. During the 17 successful flights, photographs were captured every 2 seconds. Gaps in sequential 2-second photo intervals exist because some photos were deleted because of bad exposure, slow shutter speed, excessive tilt, or low altitude during takeoff and landing. Not all of the images loaded into the photogrammetry software were used in the reconstruction. Some were omitted automatically because they yielded an insufficient number of tie points relating them to the others. Location and attitude information was calculated for all of the images used in the reconstruction, and that information is provided for only for those photos. A total of 1175 photos were imported into the Braddock West project (at the processor's discretion, some photos, usually those from the take-off and landing, were omitted). Photos that were not aligned in the project are included in this data table but have the no-data value (NaN) for all of the processed data fields. To minimize the effects of changing environmental factors (e.g. shadows, lighting, etc) on the final products, the BraddockWest photogrammetry project contains only imagery from flights on July 10, 2017.
  5. How consistent are the relationships among the observations, including topology?
    Coordinates recorded for each record describe discrete positions in space and the visual reflectance at the time of capture and the estimated position based on automated alignment done by the photogrammetry software. Agisoft Photoscan software determines the photos used in the construction of the products (Point Cloud, DEM and Orthomosaic) based on the ability to align the photo and the usability of valid tie points within an image. Images that were not successfully aligned but were imported into the software retain the original camera (image) position data but have the no-data value (NaN) for all of the processed data fields. Some photos from each flight were not loaded into photoscan by the processor. These photographs are typically from takeoff and landing, and were eliminated to reduce the total number of photographs within the project. A small number of additional photos were not included in Photoscan because of drop outs in the GPS signal that prevented the photos from being geotagged using Mission Planner (version 1.3.49). However, these photos that were omitted from the Photoscan projects have been provided in the photo zip files in this publication for completeness. All of the photos were re-geotagging using the ExifTool software, which may result in slightly different original camera position estimates between the original camera positions reported in this file and the photo position recorded in the EXIF header of the JPEG images.

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 dataset contains the CSV file with camera locations (2017042FA_BraddockWest_CameraLocations.csv), a browse graphic (2017042FA_BraddockWest_CameraLocations_browse.jpg), and FGDC CSDGM compliant metadata.
  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: 07-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)

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