Digital surface model representing Marconi Beach, Wellfleet on March 11, 2022

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Frequently anticipated questions:

What does this data set describe?

Title:
Digital surface model representing Marconi Beach, Wellfleet on March 11, 2022
Abstract:
The data in this release map the beach and nearshore environment at Marconi Beach in Wellfleet, MA and provide updated environmental context for the 2021 CoastCam installation that looks out at the coast shared by beachgoers, shorebirds, seals, and sharks. This is related to the field activity 2022-014-FA and a collaboration with the National Park Service at Cape Cod National Seashore to monitor the region that falls within the field of view of CoastCam CACO-02, which are two video cameras aimed at the beach. In March 2022, U.S Geological Survey and Woods Hole Oceanographic Institute (WHOI) scientists conducted field surveys to map the CoastCam field of view. Elevation data were collected using a real time kinematic satellite navigation system (RTK-GNSS) receiver attached to a pole and walked on the beach. Images of the beach for use in structure from motion were taken with a camera (SONY a6000) and a post-processing kinematic (PPK) system attached to a helium filled balloon-kite (Helikite). High-precision targets (AeroPoints) and plastic tarps were used as ground control points to georeference the imagery. Bathymetry was collected in the nearshore using a single-beam echosounder mounted on a surf capable self-righting electric autonomous surface vehicle. Agisoft Metashape (v. 1.8.1) was used to create an orthomosaic and digital surface model, which was merged with the bathymetry in MatLab (v. 2020b) to create a continuous topobathy product.
Supplemental_Information:
For more information about the WHCMSC Field Activity, see https://cmgds.marine.usgs.gov/fan_info.php?fan=2022-014-FA.
  1. How might this data set be cited?
    Over, Jin-Si R., 20221006, Digital surface model representing Marconi Beach, Wellfleet on March 11, 2022: data release DOI:10.5066/P9L1KCQB, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Over, Jin-Si R., Sherwood, Chris R., Traykovski, Peter A., and Bartlett, Marie K., 2022, Topographic and bathymetric data, structure from motion imagery, and ground control data collected at Marconi Beach, Wellfleet, MA in March 2022, U.S Geological Survey Field Activity 2022-014-FA: data release DOI:10.5066/P9L1KCQB, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Over, J.R., Sherwood, C.R., Traykovski, P.A., and Bartlett, M.K., 2022, Topographic and bathymetric data, structure from motion imagery, and ground control data collected at Marconi Beach, Wellfleet, MA in March 2022, U.S Geological Survey Field Activity 2022-014-FA: U.S Geological Survey data release, https://doi.org/10.5066/P9L1KCQB.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -69.96472826
    East_Bounding_Coordinate: -69.96178653
    North_Bounding_Coordinate: 41.89585853
    South_Bounding_Coordinate: 41.89076661
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/62deec39d34e952be9094198?name=2022014FA_Marconi_DSM_browse.JPG&allowOpen=true (JPEG)
    Elevation-colored image of topography data collected on Marconi Beach, Wellfleet MA in March 2022.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 11-Mar-2022
    Currentness_Reference:
    ground condition; represents the state of the beach on March 11, 2022.
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 2252 x 952, type Pixel
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 19
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -69.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 0.25
      Ordinates (y-coordinates) are specified to the nearest 0.25
      Planar coordinates are specified in meters
      The horizontal datum used is North American Datum of 1983 (National Spatial Reference System 2011).
      The ellipsoid used is GRS_1980.
      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, geoid 18
      Altitude_Resolution: 0.001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    2022014FA_Marconi_DSM_25cm_cog.tif
    A raster dataset (cloud-optimized GeoTIFF format) with encoded elevation values of Marconi Beach in Wellfleet, MA on March 11, 2022. Pixel resolution is 10 cm. (Source: producer defined)
    Value
    Surface elevation orthometric height NAVD88 (m) using Geoid 2018 in NAD83(2011) UTM Zone 19N (Source: producer defined)
    ValueDefinition
    -3.4028234663852886e38No data
    Range of values
    Minimum:-0.606
    Maximum:21.477
    Units:meters
    Entity_and_Attribute_Overview:
    Pixels represent elevation in meters relative to North American Vertical Datum of 1988 (NAVD88). The filename is formatted as "2022014FA_Marconi_DSM_25cm_cog.tif", where 2022014 is the USGS Field activity ID, location is Marconi Beach, DSM is Digital Surface Model, 25cm indicates the resolution of the grid, and cog is cloud optimized GeoTIFF.
    Entity_and_Attribute_Detail_Citation: USGS Field Activity 2022-014-FA

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Jin-Si R. Over
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Jin-Si R. Over
    U.S. Geological Survey, Woods Hole Coastal and Marine Science Center
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2297 (voice)
    jover@usgs.gov

Why was the data set created?

A high-resolution elevation dataset of Marconi Beach to observe ground conditions and temporal change and to validate the CoastCam observations.

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: Mar-2022 (process 1 of 2)
    The Digital Surface Model was created in Agisoft Metashape v. 1.8.1 using the following general steps (see Over and others, 2021 for a more detailed methodology explanation):
    1. The project was created and imagery (located in larger work citation 2022014FA_Marconi_f1.zip) and positions (located in larger work citation 2022014FA_Marconi_photolocations.csv) were imported using the NAD83(2011)/UTM19N and NAVD88 datums. An 0.15 m GNSS/IPS offset in the z direction was used to represent the approximate offset of the GNSS mount and camera on the Helikite.
    2. Photos were aligned at a low accuracy so that GCPs could be automatically detected in the point cloud. Twenty GCPs (2022014FA_Truro_nav_GCPs.csv located in the larger work citation) were found in the images and then added to the project in the reference systems NAD83(2011)/UTM Zone 19N and NAVD88. Accuracies for the GCPs were set to 0.02 m and accuracies for the camera positions were set to 10 cm, but the positions were only used as check points and to speed up alignment. The photos were re-aligned with high accuracy (the pixels were not subsampled to increase processing speed) using a keypoint limit of 40,000 and unlimited tie points. 3. The alignment process matched pixels between images to create point clouds and put the imagery into relative spatial context using the photo positions and GCPs. Then, the Metashape software refined and optimized the camera positions and lens model using least squares with gradual selection and optimization parameters of: Reconstruction uncertainty = 12, Projection accuracy = 4, and Reprojection error = 0.3 to minimize the distance between the measured points and the software-created points. 4. A dense point cloud was generated using the high-quality setting (images were not subsampled) and a low-frequency filtering algorithm. The dense point cloud was then edited to remove noise by filtering by point confidence before generating an interpolated digital elevation model (the software calls all models elevation models, but a surface model includes vegetation/canopy returns; a terrain model would be only bare earth returns). 4. The DSM product was exported at 25 cm in NAD83(2011)/UTM Zone 19N and NAVD88 (m).
    Date: Jul-2022 (process 2 of 2)
    DSM was opened in QGIS and a shapefile was created (not included in this data release) that excluded areas of interpolation and obviously erroneous elevation points on the outer edge. The DSM was then clipped to this shapefile and turned into a cloud-optimized GeoTIFF (COG) using gdal_translate with the following command: for %i in (.\*.tif) do gdal_translate %i .\cog\%~ni_cog.tif -of COG -stats -co BLOCKSIZE=256 -co COMPRESS=DEFLATE -co PREDICTOR=YES -co NUM_THREADS=ALL_CPUS -co BIGTIFF=YES (v. 3.1.4 accessed October 20, 2020 https://gdal.org/), where i is the name of each GeoTIFF. Person who carried out this activity:
    Jin-Si R. Over
    U.S. Geological Survey, Woods Hole Coastal and Marine Science Center
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2297 (voice)
    jover@usgs.gov
  3. What similar or related data should the user be aware of?
    Over, Jin-Si R., Sherwood, Chris R., Traykovski, Peter A., and Marsjanik, Eric, 2022, Topographic and bathymetric data, sediment samples, structure from motion imagery, and reference mark data collected at Marconi Beach, Wellfleet in winter 2021, U.S Geological Survey Field Activity 2021-022-FA: data release DOI:10.5066/P9POZ9VH, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    This publication is the original/first survey data of Marconi Beach from 2021.
    Over, Jin-Si R., Ritchie, Andrew C., Kranenburg, Christine, Jennifer (Jenna) A. Brown, Buscombe, Daniel D., Noble, Tom, Sherwood, Christopher R., Warrick, Jonathan, and Wernette, Phillipe, 2021, Processing coastal imagery with Agisoft Metashape Professional Edition, version 1.6 Structure from motion workflow documentation: Open-File Report 2021-1039, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    This publication includes the general methodology for processing imagery in Metashape to produce digital elevation models and ortho products.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    Ground control points (GCPs) were used to constrain the products see associated metadata for details. GCP error in the Metashape project was used to assess overall error in the product.
  2. How accurate are the geographic locations?
    Navigation information was acquired from a GNSS receiver (EMLID Reach M2) in PPK mode with a Multi-band GNSS antenna that has a theoretical horizontal accuracy of 2 cm. However, using these values in Metashape returned a poor product so the accuracy was loosened to 10 cm to accommodate the unknown horizontal offset of the GPS to the camera and to rely more on the ground control points, which have a theoretical accuracy of 1-2 cm. The horizontal Root Mean Square Error (RMSE) of the GCPs was xy: 0.066, 0.046 (m). The final product was compared to the previous survey at Marconi Beach (see cross-reference) and aligned at stable points.
  3. How accurate are the heights or depths?
    The location information was acquired from a GNSS receiver (EMLID Reach M2) in PPK mode with a Multi-band GNSS antenna and hot shoe adapter with an estimated vertical accuracy of 2 cm. However, using these values in Metashape returned a poor product so the accuracy was loosened to 5 cm to rely more on the ground control points, which have a theoretical accuracy of 1-2 cm. The total vertical RMSE of the GCPs was 0.016 m. The final product was compared to the previous survey at Marconi Beach (see cross-reference) and the z differences at stable points were within 10 cm.
  4. Where are the gaps in the data? What is missing?
    The structure-from-motion process that builds the DSM uses all the available imagery and location information at the start, however not all images may align in the software to produce the final product. This model does have interpolated elevation data over holes. The model was clipped in QGIS to remove areas of poor interpolation near the edges of the raster.
  5. How consistent are the relationships among the observations, including topology?
    All data fall into expected elevation ranges compared to previous surveys (see cross reference) except for points near and offshore of the waterline, where the data returned can be noisy and may result in erroneous measurements. This is a digital surface model (DSM) and includes returns from vegetation. No-data values outside of the collected data but within the bounds set to -3.4028234663852886e38 and appear transparent in geospatial software.

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? GeoTIFF file 2022014FA_Marconi_DSM_25cm_cog.tif as a 32-bit floating point digital surface model (DSM).
  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?
    To utilize these data, the user must have an image viewer, image processing, or GIS software package capable of importing a GeoTIFF image. Free spatial data viewers or proprietary software such as ArcGIS Earth or Google Earth Pro are capable of displaying the data. See: http://www.esri.com/software/arcgis-earth, or https://www.google.com/earth/desktop/.

Who wrote the metadata?

Dates:
Last modified: 06-Oct-2022
Metadata author:
Jin-Si R. Over
U.S. Geological Survey, Woods Hole Coastal and Marine Science Center
Geographer
U.S. Geological Survey
Woods Hole, MA

508-548-8700 x2297 (voice)
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.
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_P9L1KCQB/2022014FA_DSM_meta.faq.html>
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