Charles Point 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 Sodus Bay, New York in July 2017

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  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?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   U.S. Geological Survey, 2018, Charles Point 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 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:

   • https://doi.org/10.5066/P9XQYCD0
   • https://www.sciencebase.gov/catalog/item/5b1ede6be4b092d965254a3b

   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:

   • https://doi.org/10.5066/P9XQYCD0
   • https://www.sciencebase.gov/catalog/item/5b0800a7e4b0ac450c99d116

   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 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: -76.967715
   East_Bounding_Coordinate: -76.948530
   North_Bounding_Coordinate: 43.272983
   South_Bounding_Coordinate: 43.269200
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/5b1ede6be4b092d965254a3b/?name=2017042FA_CharlesPt_CameraLocations_browse.jpg (JPEG)

   Browse image of the camera locations

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 12-Jul-2017

   Ending_Date: 13-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 (1034)
   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?

   Charles Point 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 original camera format (Source: U.S. Geological Survey) character set of original photograph filename.

   X/Easting

   Easting coordinate of the camera in UTM Zone 18 meters, NAD83 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 unpublished photo EXIF GPS-tags. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	340322.8321
   Maximum:	341875.5865
   Units:	meters

   Y/Northing

   Northing coordinate of the camera in UTM Zone 18 meters, NAD83 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 unpublished photo EXIF GPS-tags. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	4792572.103
   Maximum:	4793006.434
   Units:	meters

   Z/Altitude

   Orthometric height of the camera in NAD83 as determined by the UAS-attached GPS and applied to photo during 'geotagging'. These altitudes were converted from WGS84 (ellipsoidal heights) to NAD83 (orthometric heights), 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:	77.400049
   Maximum:	178.570049
   Units:	meters

   Error_(m)

   total difference (in meters) between the initial coordinates from the UAS GPS log (included 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:	40.483827
   Units:	meters

   X_error

   X difference (in meters) between the initial Easting coordinates from the UAS GPS log (included in the photograph EXIF GPStags header) and the coordinates estimated from the photogrammetric reconstruction. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	-39.36085
   Maximum:	39.262857
   Units:	meters

   Y_error

   Y difference (in meters) between the initial Northing coordinates from the UAS GPS log (included in the photograph EXIF GPStags header) and the coordinates estimated from the photogrammetric reconstruction. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	-40.208286
   Maximum:	35.73225
   Units:	meters

   Z_error

   Z difference (in meters) between the initial altitude coordinates from the UAS GPS log (included in the photograph EXIF GPStags header) and the coordinates estimated from the photogrammetric reconstruction. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	-15.469411
   Maximum:	11.484108
   Units:	meters

   X_est

   X-coordinate of the camera in UTM Zone 18 meters, NAD83 estimated from the photogrammetric reconstruction using ground control points (Source: U.S. Geological Survey)

   Range of values
   Minimum:	340358.2527
   Maximum:	341871.3413
   Units:	meters

   Y_est

   Y-coordinate of the camera in UTM Zone 18 meters, NAD83 estimated from the photogrammetric reconstruction using ground control points (Source: U.S. Geological Survey)

   Range of values
   Minimum:	4792570.403
   Maximum:	4792970.572
   Units:	meters

   Z_est

   Z-coordinate (altitude) of the camera in NAVD88 estimated from the photogrammetric reconstruction using ground control points. Height in meters above NAVD88 (Source: U.S. Geological Survey)

   Range of values
   Minimum:	82.256573
   Maximum:	179.542357
   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:	0.03266
   Maximum:	359.962305
   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:	-22.634896
   Maximum:	43.684926
   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:	-39.045333
   Maximum:	161.697777
   Units:	degrees

   Entity_and_Attribute_Overview:

   The list of images and camera location information are provided in a CSV text file named 2017042FA_CharlesPt_CameraLocations.csv. The text contains one header line, followed by rows of data records; there are 14 columns of data separated by commas. If the image was not successfully aligned in the photogrammetric reconstruction, estimated camera location and attitude are not available, and only the first four 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?

How was the data set created?

1. From what previous works were the data drawn?

   geotagged images (source 1 of 2)

   U.S. Geological Survey, unpublished material, Field geotagged aerial imagery (or whatever title you want).

   Type_of_Source_Media: raster digital images
   Source_Contribution:

   These are the images geotagged in the field and used to produce the subsequent photogrammetric products. The images available from the larger work citation of this data release have updated geotag information.

   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 Sodus Bay, New York in July 2017.

   Other_Citation_Details:

   available from the Larger Work citation of this dataset (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 Sodus Bay, New York, July 12 to 14, 2017: U.S. Geological Survey data release, https://doi.org/10.5066/P9XQYCD0.)

   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)

   Images imported into Photoscan (Agisoft Photoscan Professional v. 1.3.2) for the Lake Ontario projects were geotagged using Mission Planner Software (version 1.3.49). These digital images were taken approximately 80 and 100 m above the ground on July 12 - 14, 2017, with a Ricoh GRII digital camera mounted in a 3DR Solo quadcopter operated the U.S. Geological Survey. These camera locations are the product from one of several photogrammetry projects from field activity 2017-042-FA. Four projects incorporated flights over Sodus Bay on July 12 to 14, 2017 (Lake Bluffs, Charles Point, Sodus North, and Greig Street). The projects combined images with ground control points to produce geolocated, colored (red-green-blue schema) point clouds. This camera location file, for the Charles Point project, was created using a standard processing flow as described in the steps below. 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 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 letting the software automatically detect markers where it finds all of the 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 files, 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_Charles_Crescent_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 renamed to 2017042FA_CharlesPt_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: 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?
   
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 dataset 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. However, there are several sources of potential error that affect the horizontal accuracy:
   1. The horizontal error estimate provided by Agisoft Photoscan for the Charles Point project as a result of alignment, optimization, and ground control processing procedures is 10.85 cm. This value is an RMS estimate of positional error at discrete locations within the orthomosaic.
   2. Ground control points were collected using a Spectra model SP80 GNSS receiver set to record XY locations with the national adjustment of 2011 (NAD83(2011) UTM zone 18N EPSG::6347), which differs from the Photoscan project coordinate system (NAD83/UTM zone 18N (EPSG::26918)). This difference may introduce an average additional 0.9 cm horizontally at the 95% confidence level according to the National Geodetic Survey (https://www.ngs.noaa.gov/web/surveys/NA2011/).
   3. Additionally, an assessment of repeated survey sites including transect points and ground control points, using the same equipment by the USGS Aerial Imagery and Mapping (AIM) group estimates an accuracy of the ground control point locations of 1.76 cm (horizontal) and 0.54 cm (vertical).
   The combination of the potential horizontal error is on the order of 13.5 cm for the Charles Point products. Although some portions of the map may contain much larger errors, greater than 2 m horizontally, especially along the boundary of the project that are far from a ground control point, and across water bodies. The horizontal coordinate system for the Charles Point Point Cloud, DEM and Orthomosaic is NAD83/UTM zone 18N (EPSG::26918).
   It is also important to note: The UAS image locations are derived from a mRo GPS (u-Blox Neo-M8N / 3DR SOLO Upgrade), located on the UAS, which receives signals from GPS and GLONASS satellites in WGS84 (G1150) EPSG::7660. This location information is used by the Photoscan software to help with the initial alignment, however after photo alignment, these location data have no bearing on the project or the derivative product. Therefore the positional accuracy and potential errors of the GPS data attached to the input photographs is not propagated to the Photoscan project and therefore does not contribute to the overall horizontal accuracy of the products (Point Cloud, DEM and Orthomosaic).
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. However, there are several sources of potential error that affect the vertical accuracy:
   1. The vertical error estimate provided by Agisoft Photoscan for the Charles Point project as a result of alignment, optimization, and ground control processing procedures is 0.97 cm. This value is an RMS estimate of positional error at discrete locations within the orthomosaic.
   2. Ground control points were collected using a Spectra model SP80 GNSS receiver that was receiving real-time differential corrections from a GNSS base station established in Sodus Bay NY. The Z heights were reference to the NAVD88 vertical datum. An assessment of repeated survey sites using the same equipment by the USGS Aerial Imagery and Mapping group estimates a potential accuracy error of the ground control point locations of 1.76 cm (horizontally) and 0.54 cm (vertically).
   The combination of the potential vertical error is on the order of 2.0 cm for the photogrammetric products. Although some portions of the map may contain much larger errors, greater than 20 m vertically, especially along the boundary of the project that are far from a ground control point, and across water bodies. The vertical datum for the Charles Point Point Cloud, DEM and Orthomosaic is NAVD88 (meters).
   It is also important to note: The UAS image locations are derived from a mRo GPS (u-Blox Neo-M8N / 3DR SOLO Upgrade), located on the UAS, which receives signals from GPS and GLONASS satellites in WGS84 (G1150) EPSG::7660. This location information is used by the Photoscan software to help with the initial alignment, however after photo alignment, these location data have no bearing on the project or the derivative product. Therefore the positional accuracy and potential errors of the GPS data attached to the input photographs is not propagated to the Photoscan project and therefore does not contribute to the overall vertical accuracy of the products (Point Cloud and DEM).
4. Where are the gaps in the data? What is missing?
   Eighteen (f23-f40) UAS flights were conducted in Sodus Bay survey areas along the NY Lake Ontario shoreline. Flights 27-30 are included in the Charles Point project. During the successful flights, photographs were captured every 2 seconds. Gaps in sequential 2 second photo intervals exist because some photos were deleted, for example, because of overexposure, or multiple photos of the landing pad per flight as the UAS was taking off 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 were calculated for all of the images used in the reconstruction, and that information is provided for those photos. A total of 1648 photos were imported into the Lake Bluffs project. Photos what 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.
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, but have been provided in the photo zip files in this publication.

How can someone get a copy of the data set?

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 is a CSV file with camera locations (2017042FA_CharlesPt_CameraLocations.csv), a browse graphic (2017042FA_CharlesPt_CameraLocations_browse.jpg), and FGDC CSDGM compliant metadata in XML format.
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?
   • Availability in digital form:

     Data format:	A CSV files with camera locations (2017042FA_CharlesPt_CameraLocations.csv) and FGDC CSDGM compliant metadata in XML. in format CSV Size: 0.14
     Network links:	https://www.sciencebase.gov/catalog/item/5b1ede6be4b092d965254a3b https://www.sciencebase.gov/catalog/file/get/5b1ede6be4b092d965254a3b https://doi.org/10.5066/P9XQYCD0

   • Cost to order the data: none

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: 19-Mar-2024

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)

whsc_data_contact@usgs.gov

Contact_Instructions:

The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240319)

Metadata standard:

Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)