Lidar points, elevation models, imagery, orthomosaic, and supporting GPS data collected during UAS operations at Marconi Beach, CACO, Wellfleet, MA on March 06, 2025

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Frequently anticipated questions:

What does this data set describe?

Title:
Lidar points, elevation models, imagery, orthomosaic, and supporting GPS data collected during UAS operations at Marconi Beach, CACO, Wellfleet, MA on March 06, 2025
Abstract:
Surveys with Uncrewed Systems (UxS) were used to collect remote sensing data at Marconi Beach on Cape Cod National Seashore, Wellfleet, Massachusetts after the area experienced multiple erosion events after fall storms in 2024 and the loss of National Park Service beach access stairs. The USGS has a stationary camera system (CoastCam) and meteorological station north of the parking lot on the bluff to observe waves and total water levels. UxS were approved to map the coast in view of the CoastCam and where the Park Service stairs were destroyed to help evaluate the conditions of the site and monitor landscape change from storm impacts. The data products will also help validate the CoastCam imagery datasets. Between September 2024 and March 2025, USGS personnel surveyed five times and collected natural (RGB) color images, lidar data, GPS data, and bathymetric data to produce elevation maps and orthomosaics.
Supplemental_Information:
For more information about the WHCMSC Field Activity, see https://cmgds.marine.usgs.gov/services/activity.php?fan=2025-005-FA. Images can be viewed or downloaded on the USGS Imagery Data System here https://cmgds.marine.usgs.gov/idsviewer/data_release/10.5066-P1Z9NCQX in the collection 2025_Marconi_Mar_YSMP. Note that the bounding coordinates are for the entire area and not individual files.
  1. How might this data set be cited?
    Over, Jin-Si R., and Brosnahan, Sandra M., 20251126, Lidar points, elevation models, imagery, orthomosaic, and supporting GPS data collected during UAS operations at Marconi Beach, CACO, Wellfleet, MA on March 06, 2025: data release DOI:10.5066/P1Z9NCQX, 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., Brosnahan, Sandra M., Cramer, Jennifer M., Sherwood, Chris R., and Traykovski, Peter A., 2025, Topographic and bathymetric data, aerial imagery, and GPS data collected during UxS operations at Marconi Beach, Cape Cod National Seashore, Massachusetts between September 2024 and March 2025: data release DOI:10.5066/P1Z9NCQX, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Over, J.R., Brosnahan, S.M., Cramer, J.M., Sherwood, C.R., and Traykovski, P.A., 2025, Topographic and bathymetric data, aerial imagery, and GPS data collected during UxS operations at Marconi Beach, Cape Cod National Seashore, Massachusetts between September 2024 and March 2025: U.S. Geological Survey data release, https://doi.org/10.5066/P1Z9NCQX.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -69.96652807
    East_Bounding_Coordinate: -69.96126402
    North_Bounding_Coordinate: 41.89807834
    South_Bounding_Coordinate: 41.88941496
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/67ca1895d34ed3737708cd22?name=2025-005-FA_Marconi_Mar_data_browse.png&allowOpen=true (PNG)
    Data and products of Marconi Beach in March 2025: Lidar point cloud, RGB imagery, digital elevation model, and orthomosaic.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 06-Mar-2025
    Currentness_Reference:
    Ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: point cloud, raster, and tabular digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    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 0.001
      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 (National Spatial Reference System 2011).
      The ellipsoid used is GRS_1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      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: 0.001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    2025005FA_Marconi_Mar_YSMP_ImageLocations.csv
    The CSV file contains the approximate position of the YSMP images at the moment of each capture. (Source: producer defined)
    ImageName
    File names of individual images, see the Process Description for file naming convention. (Source: USGS) Character string.
    GPSDateTime
    Date and UTC time in YYYY:MM:DD HH:MM:ss (Source: Processor defined) Character string.
    Latitude NAD83[2011]
    Latitude (x) of UAS based on time of each image capture. Positive values represent North coordinates. (Source: USGS)
    Range of values
    Minimum:41.88947222
    Maximum:41.89802500
    Units:decimal degrees
    Longitude NAD83[2011]
    Longitude (y) of UAS based on time of each image capture. Negative values represent West coordinates. (Source: USGS)
    Range of values
    Minimum:-69.96635000
    Maximum:-69.96148889
    Units:decimal degrees
    Ellipsoid height NAD83[2011]
    Altitude of the UAS position at the time of each image capture relative to the NAD83(2011) reference ellipsoid GRS80. (Source: USGS)
    Range of values
    Minimum:28.700
    Maximum:65.000
    Units:meters
    Easting 19N
    Post-processed interpolated X-coordinate of UAS based on time of each image capture NAD83(2011)/UTM Zone 19N. (Source: USGS)
    Range of values
    Minimum:419840.446
    Maximum:420234.072
    Units:meters
    Northing 19N
    Post-processed interpolated Y-coordinate of UAS based on time of each image capture NAD83(2011)/UTM Zone 19N. (Source: USGS)
    Range of values
    Minimum:4637952.759
    Maximum:4638903.906
    Units:meters
    Orthometric height NAVD88
    Post-processed Z-coordinate of the UAS at the time of each image capture relative to NAVD88 with GEOID 18 applied. (Source: USGS)
    Range of values
    Minimum:56.499
    Maximum:92.794
    Units:meters
    2025005FA_Marconi_Mar_AeroPoints.csv
    Ground control point positions, elevations, and attributes (Source: USGS)
    FAN
    USGS Field Activity Number (Source: USGS)
    ValueDefinition
    2025-005-FAYear, USGS ID, and Field Activity
    Date
    Calendar date of collection (Source: USGS)
    ValueDefinition
    20250306YYYYMMDD
    Point ID
    Unique point identification number. (Source: Processor defined)
    Range of values
    Minimum:1
    Maximum:10
    Attributes
    Unique identifier for ground control points. Prefix AP-### refers to AeroPoint2 and the last 3 digits of its identifying code. (Source: producer defined) Character string.
    Latitude NAD83[2011]
    Post-processed latitude of AeroPoint2 position (NAD83[2011]). (Source: USGS)
    Range of values
    Minimum:41.88988179
    Maximum:41.89494481
    Units:decimal degrees
    Longitude NAD83[2011]
    Post-processed longitude of AeroPoint2 position (NAD83[2011]). (Source: USGS)
    Range of values
    Minimum:-69.96501662
    Maximum:-69.96228318
    Units:decimal degrees
    Ellipsoid height NAD83[2011]
    Post-processed height in meters of AeroPoint2 in relation to the NAD83(2011) reference ellipsoid GRS80. (Source: USGS)
    Range of values
    Minimum:-14.029
    Maximum:-7.689
    Units:meters
    Easting 19N
    Post-processed interpolated X-coordinate of AeroPoint2 in NAD83(2011)/UTM Zone 19N. (Source: USGS)
    Range of values
    Minimum:419947.267
    Maximum:420168.330
    Units:meters
    Northing 19N
    Post-processed interpolated Y-coordinate of AeroPoint2 in NAD83(2011)/UTM Zone 19N. (Source: USGS)
    Range of values
    Minimum:4637997.684
    Maximum:4638561.794
    Units:meters
    Orthometric height NAVD88
    Post-processed Z-coordinate of AeroPoint2 using NAVD88 with GEOID 18 applied. (Source: USGS)
    Range of values
    Minimum:13.769
    Maximum:20.108
    Units:meters
    Xvar mm
    Variance in the X-coordinate from post-processing (Source: producer defined)
    Range of values
    Minimum:0.2
    Maximum:4.2
    Units:millimeters
    Yvar mm
    Variance in the Y-coordinate from post-processing (Source: producer defined)
    Range of values
    Minimum:0.6
    Maximum:4.6
    Units:millimeters
    Zvar mm
    Variance in the Z-coordinate from post-processing (Source: producer defined)
    Range of values
    Minimum:0.2
    Maximum:9.9
    Units:millimeters
    Baseline distance km
    distance of AeroPoint2 from nearest used processing network base station (Source: Propeller)
    Range of values
    Minimum:0.05
    Maximum:11.80
    Units:kilometers
    2025005FA_Marconi_Mar_GPS_Emlid_RS3.csv
    GPS positions, elevations, and attributes (Source: USGS)
    FAN
    USGS Field Activity Number (Source: USGS)
    ValueDefinition
    2025-005-FAYear, USGS ID, and Field Activity
    Date
    Calendar date of collection (Source: USGS)
    ValueDefinition
    20250306YYYYMMDD
    Point ID
    Unique point identification number. NaN assigned to reference point pre-loaded into project. Discontinuous as points unrelated camera calibration were removed. (Source: Processor defined)
    Range of values
    Minimum:1
    Maximum:56
    Attributes
    Identifier for GPS check shots. OPUS MAR-RM2 refers to the known solution of reference mark 2 at Marconi Beach, prefix 'stake' refers to a check in on the reference mark either at the beginning ('OPEN') or at the end ('CLOSE') of the survey, AP-### refers to a surveyed AeroPoint2, and 'transect' refers to a check point taken along a line from the bluff to the water. The prefix CACO-04 refers to the CoastCam and then what was measured; camera 1 (c1), camera 2 (c2), the bracket, or the bracket hole. (Source: producer defined) Character string.
    Latitude NAD83[2011]
    RTK x position of the point relative to (NAD83[2011]). (Source: USGS)
    Range of values
    Minimum:41.89115682
    Maximum:41.89280205
    Units:decimal degrees
    Longitude NAD83[2011]
    RTK y position of the point relative to (NAD83[2011]). (Source: USGS)
    Range of values
    Minimum:-69.96377348
    Maximum:-69.96305189
    Units:decimal degrees
    Ellipsoid height NAD83[2011]
    RTK z position of the point relative to the NAD83(2011) reference ellipsoid GRS80. (Source: USGS)
    Range of values
    Minimum:-14.892
    Maximum:-9.964
    Units:meters
    Easting 19N
    RTK x position of the point relative to NAD83(2011)/UTM Zone 19N. (Source: USGS)
    Range of values
    Minimum:420048.086
    Maximum:420107.156
    Units:meters
    Northing 19N
    RTK y position of the point relative to NAD83(2011)/UTM Zone 19N. (Source: USGS)
    Range of values
    Minimum:4638140.368
    Maximum:4638322.846
    Units:meters
    Orthometric height NAVD88
    RTK z position of the point relative to NAVD88 with GEOID 18 applied. (Source: USGS)
    Range of values
    Minimum:12.909
    Maximum:17.836
    Units:meters
    Tilt angle
    Angle to nadir of the Emlid RS3 (Source: USGS)
    Range of values
    Minimum:0.0
    Maximum:5.3
    Units:degrees
    Elevation RMS m
    Root mean square in the Z-coordinate (Source: producer defined)
    Range of values
    Minimum:0.011
    Maximum:0.020
    Units:meters
    Lateral RMS m
    Root mean square in the horizontal XY-coordinate (Source: producer defined)
    Range of values
    Minimum:0.017
    Maximum:0.021
    Units:meters
    Baseline m
    Distance from the rover to the base station. A value of NaN is present for the OPUS solution which does not have a baseline value. (Source: producer defined)
    Range of values
    Minimum:4.293
    Maximum:138.962
    Units:meters
    2025005FA_Marconi_Mar_YSMP_LPC.laz
    UAS lidar point cloud in *.laz file format. This georeferenced point cloud was colorized using natural color RGB image values and is not classified. There are 67,336,323 points. Point density is 372.59 points per square meter and point spacing is 0.052 m. (Source: producer defined)
    Elevation
    Surface elevation in EPSG:5703 using GEOID 18. (Source: YellowScan CloudStation)
    Range of values
    Minimum:-1.206
    Maximum:25.708
    Units:meters
    Intensity
    Lidar intensity is recorded as the return strength of a laser beam during data collection. Value is scaled 16-bit integer from 0 to 65,535) (Source: YellowScan CloudStation)
    Range of values
    Minimum:0
    Maximum:65,025
    Units:none
    2025005FA_Marconi_Mar_YSMP_Lidar_DSM_25cm.tif
    A cloud-optimized deflate compressed digital surface model created from the lidar point cloud maximum values with encoded elevation values. Pixel resolution is 25 cm. No-data value is –3.4028e+38. (Source: USGS)
    Value
    Surface elevation in EPSG:5703 using GEOID 18. (Source: producer defined)
    Range of values
    Minimum:-1.206
    Maximum:25.708
    Units:meters
    2025005FA_Marconi_Mar_YSMP_Ortho_5cm.tif
    Cloud-optimized deflate compressed true-color (RGB) orthomosaic. (Source: USGS)
    Band_1
    Red wavelength band (Source: Agisoft Metashape)
    Range of values
    Minimum:0
    Maximum:255
    Band_2
    Green wavelength band (Source: Agisoft Metashape)
    Range of values
    Minimum:0
    Maximum:255
    Band_3
    Blue wavelength band (Source: Agisoft Metashape)
    Range of values
    Minimum:0
    Maximum:255
    Entity_and_Attribute_Overview:
    The filenames are formatted as "2025005FA_Marconi_Mar_sensor/product_resolution.*** ", where 2025005 is the USGS Field activity ID, location is Marconi Beach (Marconi), Mar is month of data collection, sensors are YellowScan Mapper Plus (YSMP), AeroPoints, Emlid RS3, and products include structure from motion (SfM) orthomosaic (Ortho), lidar derived digital surface model (DSM), and lidar point cloud (LPC).
    Entity_and_Attribute_Detail_Citation: USGS Field Activity 2025-005-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
    • Sandra M. Brosnahan
  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, Northeast Region, 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?

The imagery and AeroPoint ground control points are used to create a structure from motion (SfM) orthomosaic product and the lidar is used to produce a point cloud and an elevation model. The GPS points are used to validate the accuracy of the products. The dataset is used to evaluate the recovery from the nor’easter on September 22, 2024 that destroyed the beach access stairs and will help monitor landscape change from additional storm impacts.

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: 06-Mar-2025 (process 1 of 6)
    GROUND CONTROL: Ten AeroPoint2 GCPs were spaced out over the field site and left on for at least 30 minutes to collect GNSS data. After collection the AeroPoint2s data were uploaded via a Wi-Fi connection and run through a post-processing kinematic algorithm of the Propeller Corrections Network to get corrected positions. The data were exported in NAD83(2011) (EPSG:6318) to produce latitude, longitude, and ellipsoid heights, and then NAD83(2011)/UTM zone 19N (EPSG:6348) and NAVD88 (EPSP:5703) with GEOID 18 to produce easting and northing and orthometric heights. These were exported to a CSV file and named 2025005FA_Marconi_Mar_AeroPoints.csv. An Emlid RS2 was set up as a base station using a RTK fix on the highest section of boardwalk to record GNSS data for post processing the lidar data. An Emlid RS3 with tilt compensation was connected to the base to take RTK three-second averaged check shots of the bluff, beach, and AeroPoint2s; data were provided in 2025005FA_Marconi_Mar_GPS_Emlid_RS3.csv Step processed by J. Over and S. Brosnahan and assisted by Amit Millo.
    Date: 06-Mar-2025 (process 2 of 6)
    UAS FLIGHTS: The lidar sensor was a 905 nm wavelength Livox Avia with a 70.4/4.5 degree horizontal and vertical field of view (FOV). A configuration text file that controls camera triggering height, the camera triggering interval, and the lidar scan pattern was pre-loaded onto a 256 GB USB thumb drive. The lidar scanner was set to a repetitive (linear back and forth) motion optimal for unvegetated surfaces. The camera module is a SONY UMC - 10RC, which takes a 20 megapixel (MP) photo. The system also consists of a Trimble AV18 GNSS antenna mounted to the top of the UAS and connected to the lidar system via GNSS cable. The lidar data was saved to the thumb drive in three different files: (1) the IMU/GPS data, decimated for quick post-processing, in binary *.ys format, (2) the scanner data in *.lvx format (~600 MB per minute of data collection), (3) and the complete IMU/GPS data in Applanix (Trimble) binary *.t04 format. The RGB images are saved to a 64 GB micro-SD card as *.JPG files. The YSMP was attached to a DJI Matrice 600 Pro UAS with approved government edition firmware. The YSMP lidar data were collected with the UAS flying at 10 m/s at 68 meters above ground level with north-south transect passes. The camera module was set to take images every 2 seconds. After the flight the lidar data were taken off the sensor. Note, the YSMP geotagged positions embedded in the imagery Exif information were in EPSG:4326, this is how the data were collected. The positions were converted to EPSG:6348 and EPSG:5703 in the processing software and the converted positions are reported in the imagery locations file (2025005FA_Marconi_Mar_YSMP_ImageLocations.csv) and represented in the final SfM products. Step processed by J. Over and S. Brosnahan.
    Date: 10-Mar-2025 (process 3 of 6)
    RAW IMAGERY: The YSMP images were geotagged in Emlid Studio using the lidar *.T04 file and base station RINEX files. All images were processed to add additional information required by the USGS to the Exif headers using ExifTools (https://exiftool.org/, version: 12.06), and the files were renamed to a unique identifier using Namexif (http://www.digicamsoft.com/softnamexif.html, version 2.1) to avoid any possibility of duplicate names. These steps are described here. 1. ExifTools was used to tag each photo headers following the Imagery Data System EXIF Guidance. Attributes (e.g. Credit, Copyright, UsageTerms, ImageDescription, Artist, etc) were stored in a csv file and written to each image with the command:' exiftool -csv="C:\directory\name\EXIF.csv" C:\directory\name\of\photos *.JPG ' To read out the photo information to a csv when in the directory with the photos the command is: exiftool -csv *.JPG > directory/name/allheaders_out.csv 2. All the images were renamed with Namexif (https://us.digicamsoft.com/softnamexif.html v 2.2 accessed April 2020) to ensure unique filenames and compliance with the USGS Coastal and Marine Hazards and Resources Program's best practices for image naming convention. Images were renamed with the field survey ID prefix; flight number, and ID that distinguishes USGS cameras by make/camera number, the image acquisition date, coordinated universal time (UTC) in ISO8601 format, and a suffix with the original image name. For example, image name '2025005FA_f01YSMP_20250306T165822Z_IMG_####_#', 2025005FA is the field activity ID; f01 is the flight number; YSMP is the camera on the YellowScan Mapper Plus; 20250306 is the UTC date in the format YYYYMMDD, and a 'T' is used to separate UTC date from UTC time in format HHMMSS followed by a Z. The IMG_#### is the original raw photo name appended to the end of the new filename. 3. Images are validated and uploaded onto the Imagery Data System. 4. The 2025005FA_Marconi_Mar_YSMP_ImageLocations.csv was created with the exif command: exiftool –ImageName –GPSDateTime –csv *.JPG > .\2025005FA_Marconi_Mar_YSMP_ImageLocations.csv Step processed by J. Over.
    Date: 10-Mar-2025 (process 4 of 6)
    PHOTOGRAMMETRY: The ortho product was created in Agisoft Metashape v. 2.1.4 using the following general steps (see Over and others, 2021 for a more detailed SfM methodology explanation): 1. A project was created and imagery was imported and assigned the WGS84 (EPSG:4326) reference system and then were immediately converted to EPSG: 6318 and then EPSG:6348 and EPSG:5703. These converted positions were added to the 2025005FA_Marconi_Mar_YSMP_ImageLocations.csv. 2. Photos were aligned at a low accuracy and then GCPs were automatically detected in the point cloud. GCP positions (2025005FA_Marconi_Mar_AeroPoints.csv) were added to the project in the reference systems EPSG:6348 and EPSG:5703 using GEOID 18. The horizontal and vertical accuracies for the GCPs were set to 0.01/0.02 m, respectively and the camera positions for the images were turned off. The photos were then re-aligned with high accuracy (the pixels were not subsampled) using a keypoint limit of 60,000 and unlimited tie points. 3. The alignment process matched pixels between images to create point clouds and put the imagery into a relative spatial context using the GCPs. The resultant point clouds were filtered using one iteration of the 'Reconstruction uncertainty' filter at a level of 10, one iteration of the 'Projection accuracy' filter at a level of 3, and multiple iterations of the 'Reprojection accuracy' filter to get to a level of 0.3. With each filter, iteration points are selected, deleted, and then the camera model was optimized to refine the focal length, cx, cy, k1, k2, k3, p1, and p2 camera model coefficients. 4. In a new chunk a high quality dense cloud with a low-frequency filtering algorithm was made. The dense point cloud was then edited by visual inspection to remove points with a low confidence near the edges and near water bodies. 5. An interpolated DSM was built from the dense point cloud and then an orthomosaic was built from the DSM with refined seamlines. The orthomosaic is a 3-band orthomosaic exported at 5 cm resolution (2025005FA_Marconi_Mar_YSMP_SfM_Ortho_5cm.tif). Step processed by J. Over.
    Date: 11-Mar-2025 (process 5 of 6)
    LIDAR DATA: The YSMP lidar data were processed in YellowScan CloudStation software integrated with Trimble POSPac UAV 9.0. Raw scanner data (*.ys file) was imported into YellowScan CloudStation, the sensor LiDAR (*.profile) and Camera (*.camera) profiles, provided by the vendor, were selected for the project and the project coordinate reference system was set to EPSG:6318. CloudStation flight trajectories were adjusted manually to select the desired data to be processed. The *.T04 file and base station GNSS RINEX file were used to correct and optimize the sensor position trajectories and produce a Smoothed Best Estimate of Trajectory (SBET) file in *.txt ASCII format, which represents the Post Processing Kinematic (PPK) Solution. The lever arm offsets and boresight angle corrections were applied to the LPC, along with a strip adjustment between transect swaths using CloudStation's "robust" setting. The lidar point cloud (LPC) was colored by the YSMP camera based on the photo timestamp. Finally, the Cut Overlap function was applied to remove redundant points based on the smaller scan angle. The LPC was then exported in *.laz 1.4 in EPSG:6348. The LPC was brought into Global Mapper and manually cleaned of points interpreted to be noise or are above a reasonable elevation threshold based on the surrounding features before the data were QA/QC’d with 3DEP, GCPs, and GPS check points. After assessing the agreement with the colorization and intensity it was deemed that re-colorizing the LPC with the SfM orthomosaic would be more accurate. Then, the LPC was gridded at 0.25 m into a DSM using maximum values binning grid method and the setting 'Grid "No Data" Distance' set to 5; the resulting file was exported as 2025005FA_Marconi_Mar_YSMP_Lidar_DSM_25cm.tif. The LPC was exported as 2025005FA_Marconi_Mar_YSMP_LPC.laz. All files were exported in EPSG:6348 and EPSG:5703 using GEOID 18. Step processed by J. Over.
    Date: 12-Mar-2025 (process 6 of 6)
    CLOUD OPTIMIZATION: All GeoTIFF products were Deflate compressed and turned into a cloud-optimized GeoTIFFs (COG) using gdal_translate with the following command: for %i in (.\*.tif) do gdal_translate %i .\cog\%~ni.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 section. Step processed by J. Over. Person who carried out this activity:
    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)
    jover@usgs.gov
  3. What similar or related data should the user be aware of?
    Over, Jin-Si R., Ritchie, Andrew C., Kranenburg, Christine J., Brown, Jenna A., Buscombe, Daniel D., Noble, Tom, Sherwood, Christopher R., Warrick, Jonathan A., and Wernette, Phillipe A., 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 surface models and ortho products.

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

  1. How well have the observations been checked?
    GPS: The theoretical internal accuracy of the Emlid RS3 survey equipment is 2 cm. Points that had a FIX were assumed to be within that tolerance after staking out at known reference mark MAR-RM1 and the values were within 2 cm. The vertical and horizontal root mean square errors (RMSE) for each point were also reported in 2025005FA_Marconi_Mar_GPS_Emlid_RS3.csv. The AeroPoint2 GCPs have an internal reported variance provided in 2025005FA_Marconi_Mar_AeroPoints.csv, the global accuracy was calculated and reported below by adding the variance to twice the longest baseline distance.
    GeoTIFFs: The horizontal and vertical accuracy of the products (2025005FA_Marconi_Mar_YSMP_Lidar_DSM_25cm.tif and 2025005FA_Marconi_Mar_YSMP_SfM_Ortho_5cm.tif) were assessed using the AeroPoint2 ground control points (GCPs) and check points. It should also be noted that accuracy estimates of the products are for areas of bare ground or low vegetation where GCPs were placed or check points taken. Additional sources of error, such as moving objects, may cause accuracy estimates to exceed estimates in localized portions of the products.
    Lidar: The point cloud (2025005FA_Marconi_Mar_YSMP_LPC.laz) positional accuracy is based on the GPS/IMU and post positional corrections from the base station but the vertical point spread on a flat surface is about 8 cm. The colorization is based on the SfM orthomosaic and may be off by up to 20 cm. Some misalignment in the collected lidar strips may occur. Users are advised to evaluate the data for their own needs.
  2. How accurate are the geographic locations?
    Images: The YSMP images were geotagged with the post-processed lidar *.T04 file and Emlid RS2 base station data and had an average xy accuracy of 0.02 m.
    GPS: Emlid RS3 GPS points have a xy RMSE average of 2 cm. AeroPoint2 horizontal global accuracy is 2.8 cm.
    Lidar: The lidar point cloud, and by association the DSM, horizontal accuracy was assessed against positions of the AeroPoint2s in the intensity view (not the RGB). The horizontal accuracy is variable and within 30 cm.
    SfM: The orthomosaic was spatially georeferenced using AeroPoint2 GCPs (n=10) and created using SfM. The horizontal RMSE of the check points as reported from the Metashape projects were x/y 0.024/0.025 m.
  3. How accurate are the heights or depths?
    Images: The YSMP images were geotagged with the post-processed lidar *.T04 file and base station data and had an average z accuracy of 0.1 m. GPS: Emlid RS3 GPS points have a z RMSE average of 1 cm. AeroPoint2 global vertical accuracy is 3.5 cm.
    Lidar: The lidar point cloud was assessed against USGS 3DEP (https://www.usgs.gov/3d-elevation-program) surface, and the vertical difference on the parking lot surface is within 15 cm. The lidar based DSM was assessed against the elevations of the AeroPoint2s and RTK points: the RMSE (n=67) was 0.04 cm.
  4. Where are the gaps in the data? What is missing?
    GCPs: Due to lack of access, no AeroPoints were placed on the beach. Imagery: The YSMP camera triggered every 2 seconds. Images were removed at takeoff and landing. A total of 364 YSMP images are on the IDS and were used to make the SfM products. Products: GeoTIFF products are cloud-optimized and Deflate compressed. The LPC has been cleaned in Global Mapper to remove water points and wave noise. The total area covered by the YSMP photos was much larger than where the AeroPoint2 GCPs were placed (n=10), leading to less accurate results on the outer edges of the structure from motion (SfM) surfaces, beyond (~100 meters) the GCP placement. To reduce the extent of the errors the extent of the final orthomosaic product was cropped to a smaller area covered by the AeroPoint2s but still encompasses the areas in view of the CoastCam.
  5. How consistent are the relationships among the observations, including topology?
    There was one UAS flight and ten AeroPoint2 GCPs. The flight (17 min) used the YellowScan Mapper Plus (YSMP) on the M600 to collect lidar data and RGB images and produced the lidar point cloud (LPC), orthomosaic, and digital surface model (DSM). An Emlid RS2 was set up as a base station to record GNSS data and an Emlid RS3 was used to collect 55 check shots.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints No access constraints. Please see 'Distribution Information' for details.
Use_Constraints These data are marked with a Creative Commons CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Please recognize the U.S. Geological Survey (USGS) as the source of this information. These data are not intended for navigational use.
  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? Aerial imaging and mapping of Marconi Beach includes the imagery (YSMP), orthomosaic, the YSMP lidar point cloud, digital surface model, Emlid GPS check points, and AeroPoint2 ground control points.
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Not for navigational use.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 26-Nov-2025
Metadata author:
Jin-Si R. Over
U.S. Geological Survey, Northeast Region
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_P1Z9NCQX/2025-005-FA_Marconi_Mar_metadata.faq.html>
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