Lidar point cloud, elevation models, GPS data, imagery, and orthomosaic, collected during UAS operations at Town Neck Beach, Sandwich, MA on December 19th, 2023

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?
   Over, Jin-Si R., and Cramer, Jennifer M., 2025, Lidar point cloud, elevation models, GPS data, imagery, and orthomosaic, collected during UAS operations at Town Neck Beach, Sandwich, MA on December 19th, 2023: data release DOI:10.5066/P1UBZZFA, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

   Online Links:

   • https://doi.org/10.5066/P1UBZZFA
   • https://www.sciencebase.gov/catalog/item/67213f10d34ed0f827eaaeed

   This is part of the following larger work.
   Over, Jin-Si R., Cramer, Jennifer M., Farris, Amy, and Sherwood, Christopher R., 2025, Topographic data, imagery, and GPS data collected during uncrewed aircraft system (UAS) operations at Town Neck Beach, Sandwich, Massachusetts: data release DOI:10.5066/P1UBZZFA, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/P1UBZZFA
   • https://www.sciencebase.gov/catalog/item/67213855d34ed0f827eaae83

   Other_Citation_Details:

   Over, J.R., Cramer, J.M., Farris, A., and Sherwood, C.R., 2025, Topographic data, imagery, and GPS data collected during uncrewed aircraft system (UAS) operations at Town Neck Beach, Sandwich, Massachusetts: U.S. Geological Survey data release, https://doi.org/10.5066/P1UBZZFA.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -70.48839210
   East_Bounding_Coordinate: -70.47266159
   North_Bounding_Coordinate: 41.77067666
   South_Bounding_Coordinate: 41.76186184
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/67213f10d34ed0f827eaaeed?name=2023028FA_TNB_data_browse.png&allowOpen=true (PNG)

   Data and products of Town Neck Beach: RGB image, lidar point cloud, ortho, and USGS personnel.

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

   Calendar_Date: 19-Dec-2023

   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?

   2023028FA_TNB_ImageLocations.csv

   The CSV file contains the approximate position of the Ricoh GRII images at the moment of each capture based on their estimated position from the SfM processing. (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 camera based on time of each image capture. Positive values represent north coordinates. (Source: USGS)

   Range of values
   Minimum:	41.76186184
   Maximum:	41.77067666
   Units:	decimal degrees

   Longitude NAD83[2011]

   Longitude (y) of camera based on time of each image capture. Negative values represent west coordinates. (Source: USGS)

   Range of values
   Minimum:	-70.48763183
   Maximum:	-70.47423920
   Units:	decimal degrees

   Ellipsoid height GRS80

   Vertical position of the camera based on time of each capture in relation to the NAD83(2011) reference ellipsoid. (Source: None)

   Range of values
   Minimum:	58.921
   Maximum:	77.844
   Units:	meters

   Easting 19N

   X-coordinate position of the camera based on time of each capture in NAD83(2011)/UTM Zone 19N. (Source: USGS)

   Range of values
   Minimum:	376354.081
   Maximum:	377455.913
   Units:	meters

   Northing 19N

   Y-coordinate position of the camera based on time of each capture in in NAD83(2011)/UTM Zone 19N. (Source: USGS)

   Range of values
   Minimum:	4624388.209
   Maximum:	4625384.588
   Units:	meters

   Altitude NAVD88

   Altitude of the camera at the time of each image capture relative to NAVD88 using GEOID 18. (Source: None)

   Range of values
   Minimum:	87.112
   Maximum:	106.040
   Units:	meters

   2023028FA_TNB_AeroPoints.csv

   Ground control point positions, elevations, and attributes. AeroPoint AP-27C was not turned on but was surveyed with the SP80 GPS, so its position variance and baseline data was not provided from Propeller and the attributes reflect this with NaN. (Source: USGS)

   FAN

   USGS Field Activity Number (Source: USGS)

   Value	Definition
   2023-028-FA	Year, USGS ID, and Field Activity

   Date

   Calendar date of collection (Source: USGS)

   Value	Definition
   20231219	YYYYMMDD

   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 AeroPoint and the last 3 digits of its identifying code. (Source: producer defined) Character string.

   Latitude NAD83[2011]

   Post-processed latitude of AeroPoint position (NAD83[2011]). (Source: USGS)

   Range of values
   Minimum:	41.76408972
   Maximum:	41.76857353
   Units:	decimal degrees

   Longitude NAD83[2011]

   Post-processed longitude of AeroPoint position (NAD83[2011]). (Source: None)

   Range of values
   Minimum:	-70.48567046
   Maximum:	-70.47850307
   Units:	decimal degrees

   Ellipsoid height GRS80

   Post-processed height in meters of AeroPoint in relation to the NAD83(2011) reference ellipsoid. (Source: None)

   Range of values
   Minimum:	-26.471
   Maximum:	-22.516
   Units:	meters

   Easting 19N

   Post-processed interpolated X-coordinate of AeroPoint in NAD83(2011)/UTM Zone 19N. (Source: USGS)

   Range of values
   Minimum:	376513.911
   Maximum:	377101.108
   Units:	meters

   Northing 19N

   Post-processed interpolated Y-coordinate of AeroPoint in NAD83(2011)/UTM Zone 19N. (Source: USGS)

   Range of values
   Minimum:	4624640.213
   Maximum:	4625148.312
   Units:	meters

   Orthometric height NAVD88

   Post-processed Z-coordinate of AeroPoint using NAVD88 with GEOID 18 applied. (Source: USGS)

   Range of values
   Minimum:	1.720
   Maximum:	5.671
   Units:	meters

   Xvar mm

   Internal variance in the X-coordinate from post-processing. No data value is NaN. (Source: producer defined)

   Range of values
   Minimum:	1.6
   Maximum:	18.3
   Units:	millimeters

   Yvar mm

   Internal variance in the Y-coordinate from post-processing. No data value is NaN. (Source: producer defined)

   Range of values
   Minimum:	3.0
   Maximum:	12.7
   Units:	millimeters

   Zvar mm

   Internal variance in the Z-coordinate from post-processing. No data value is NaN. (Source: producer defined)

   Range of values
   Minimum:	3.9
   Maximum:	13.2
   Units:	millimeters

   Baseline distance km

   Distance to from the AeroPoint to the correcting base. No data value is NaN. (Source: producer defined)

   Range of values
   Minimum:	0.35
   Maximum:	12.19
   Units:	kilometers

   2023028FA_TNB_GPS_SP80.csv

   GPS SP80 check point positions, elevations, and attributes (Source: USGS)

   FAN

   USGS Field Activity Number (Source: USGS)

   Value	Definition
   2023-028-FA	Year, USGS ID, and Field Activity

   Date

   Calendar date of collection (Source: USGS)

   Value	Definition
   20231219	YYYYMMDD

   Point ID

   Unique point identification number. (Source: Processor defined)

   Range of values
   Minimum:	1
   Maximum:	47

   Attributes

   Identifies check point type. Attributes with suffix open and close identify reference marks surveyed at the beginning (open) and end (close). Attributes labeled ‘transect’ are ground check points. Attributes with the prefix ‘aero’ are surveyed AeroPoints. (Source: producer defined) Character string.

   Latitude NAD83[2011]

   Real-time kinematic latitude of GPS point (NAD83[2011]). (Source: USGS)

   Range of values
   Minimum:	41.76409003
   Maximum:	41.76857376
   Units:	decimal degrees

   Longitude NAD83[2011]

   Real-time kinematic longitude of GPS point (NAD83[2011]). (Source: None)

   Range of values
   Minimum:	-70.48567002
   Maximum:	-70.47850289
   Units:	decimal degrees

   Ellipsoid height GRS80

   Real-time kinematic vertical position of GPS point in relation to the NAD83(2011) reference ellipsoid. (Source: None)

   Range of values
   Minimum:	-27.596
   Maximum:	-22.547
   Units:	meters

   Easting 19N

   Real-time kinematic X-coordinate of GPS point in NAD83(2011)/UTM Zone 19N. (Source: USGS)

   Range of values
   Minimum:	376513.949
   Maximum:	377101.123
   Units:	meters

   Northing 19N

   Real-time kinematic Y-coordinate of GPS point in NAD83(2011)/UTM Zone 19N. (Source: USGS)

   Range of values
   Minimum:	4624640.246
   Maximum:	4625148.336
   Units:	meters

   Orthometric height NAVD88

   Real-time kinematic Z-coordinate of GPS point relative to NAVD88 with GEOID 18 applied. (Source: USGS)

   Range of values
   Minimum:	0.595
   Maximum:	5.640
   Units:	meters

   HSDV m

   Horizontal standard deviation, provides the horizontal precision of the position solution. (Source: producer defined)

   Range of values
   Minimum:	0.008
   Maximum:	0.016
   Units:	meters

   VSDV m

   Vertical standard deviation, provides the vertical precision of the position solution. (Source: producer defined)

   Range of values
   Minimum:	0.011
   Maximum:	0.021
   Units:	meters

   2023028FA_TNB_YSMP_LPC.laz

   YSMP lidar point cloud in .laz file format. This georeferenced point cloud was colorized using natural color RGB image values and is not classified. Total point count is 105,722,322. The point density is 309.88 points per square meter, and point spacing is 0.057 m. (Source: producer defined)

   Elevation

   Surface elevation orthometric height NAVD88 (m) using GEOID 18 in NAD83(2011)/UTM Zone 19N. (Source: YellowScan CloudStation)

   Range of values
   Minimum:	-4.956
   Maximum:	15.420
   Units:	meters

   Intensity

   Lidar intensity is recorded as the return strength of a laser beam during data collection. (Source: YellowScan CloudStation)

   Range of values
   Minimum:	0
   Maximum:	65,025

   2023028FA_TNB_YSMP_DSM_25cm.tif

   A cloud-optimized digital surface model created from the lidar point cloud with encoded elevation values. Pixel resolution is 25 cm. (Source: USGS)

   Value

   Surface elevation orthometric height NAVD88 (m) using GEOID 2018 in NAD83(2011) UTM Zone 19N. (Source: producer defined)

   Range of values
   Minimum:	-1.348
   Maximum:	15.422
   Units:	meters

   2023028FA_TNB_Ricoh_SfM_DSM_25cm.tif

   A cloud-optimized digital surface model created from the Ricoh GRII images using SfM with encoded elevation values. Pixel resolution is 25 cm. (Source: USGS)

   Value

   Surface elevation orthometric height NAVD88 (m) using GEOID 2018 in NAD83(2011) UTM Zone 19N. (Source: producer defined)

   Range of values
   Minimum:	-2.971
   Maximum:	16.543
   Units:	meters

   2023028FA_TNB_Ricoh_SfM _Ortho_5cm.tif

   True-color (RGB) cloud optimized orthomosaic made from the Ricoh GRII images. (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 "2023028FA_TNB_sensor/product_resolution.*** ", where 2023028 is the USGS Field activity ID, location is Town Neck Beach (TNB); sensors include YellowScan Mapper Plus (YSMP), Ricoh GRII, GPS_SP80, and AeroPoints; products include orthomosaics (ortho), digital surface models (DSM), and lidar point cloud (LPC). The horizontal coordinate reference system for all products is NAD83(2011)/UTM19N, the vertical coordinate reference system (VCRS) is NAVD88 using GEOID 18.

   Entity_and_Attribute_Detail_Citation: USGS Field Activity 2023-028-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
   • Jennifer M. Cramer
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?

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: 19-Dec-2023 (process 1 of 6)

   GROUND CONTROL: Ten AeroPoint GCPs were spaced out over the field site and left on for at least two hours to collect Global Navigation Satellite System (GNSS) data. After collection and connected to Wi-Fi, the AeroPoint data were uploaded and run through a post-processing kinematic algorithm of the Continuously Operating Reference Station (CORS) network to get a global accuracy. The data were exported with xyz internal variances in the horizontal datum NAD83(2011) to produce latitude, longitude, and ellipsoid heights, and then UTM19N and NAVD88 using GEOID 18 was used to produce easting, northing, and orthometric heights. These were exported to a *.csv file and named 2023028FA_TNB_AeroPoints.csv. GPS DATA: A Spectra Precision 80 (SP80) was set up as a base station in the parking lot to collect RINEX data to correct the lidar data. A second SP80 was set up as a rover connected to the Massachusetts CORS network and used to take check shots in the parking lot and on a transect across the beach. The check points are provided in 2023028FA_TNB_GPS_SP80.csv. Step completed by C. Sherwood, A. Farris, J. Cramer, and J. Over.

   Date: 19-Dec-2023 (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). The lidar scanner was set to the repetitive scan pattern, which moves the sensor in a back-and-forth motion and is optimal for non-vegetated areas. The camera module (that was attached but not triggered) was a SONY UMC - 10RC, a 20.4 megapixel (MP). 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 a 256 GB USB 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 were saved to a 64 GB micro SD card as *.jpeg files. A configuration text file (CONFIG.TXT) was pre-loaded onto the USB thumb drive and can be edited to control lidar and camera module settings, including the camera triggering height, the camera triggering interval, and the lidar scan pattern. 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 7 m/s at ~61 meters above ground level at a transect spacing of 45 m for a total of 42 minutes of flight time. After each flight the lidar data were taken off the sensor. Note, the geotagged positions embedded in the Exchangeable image file format (Exif) information are WGS84 and ellipsoid height, this is how the data are collected. The positions have been converted to NAD83(2011) and NAVD88 GEOID 18 in the imagery locations file (2023028FA_TNB_ImageryLocations.csv). Step completed by J. Cramer and J. Over.

   Date: 20-Dec-2023 (process 3 of 6)

   RAW IMAGERY: The Ricoh GRII attached to the UAS M600 was set to infinity focus and a 2 second interval. The M600 was flying at 8 m/s at 100 meters above ground level at a transect interval of 40 m for a total of 28 minutes of flight time. JPEGs were taken off after the end of the flight. 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 '2023028FA_f01r03_20231219T165822Z_R#', 2023028FA is the field activity ID, f01 is the flight number, r03 is the camera, 20231219 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 R# is the original raw photo name appended to the end of the new filename. Step completed by J. Cramer and J. Over.

   Date: 31-Oct-2024 (process 4 of 6)

   PHOTOGRAMMETRY: The SfM products were created in Agisoft Metashape v. 2.0.1 using the following general steps (see Over and others, 2021 for a more detailed methodology explanation): 1. A project was created in Metashape and Ricoh GRII imagery was imported. 2. Photos were aligned at a low accuracy and then GCPs were automatically detected in the point cloud. GCP positions (2023028FA_TNB_AeroPoints.csv) were added to the project in the reference systems NAD83(2011)/UTM Zone 19N and NAVD88 (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 4, and three 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. At this point, multiple ‘chunks’ were created so that a high-quality dense cloud with a low-frequency filtering algorithm could be made from the images. The dense point cloud was then edited by visual inspection and Metashape’s confidence filter to remove points with a low confidence near the edges and near water bodies. 5. A DSM is built from the dense point cloud and then an orthomosaic is built from the DSM with refined seamlines. The DSM (2023028FA_TNB_Ricoh_SfM_DSM_25cm.tif) and orthomosaic (2023028FA_TNB_Ricoh_SfM_Ortho_5cm.tif) are exported in EPSG:6348 NAD83(2011)/UTM19N, the DSM has a vertical reference system in EPSG:5703 NAVD88 (GEOID 18). Step completed by J. Over.

   Date: 02-Nov-2024 (process 5 of 6)

   LIDAR DATA: The YSMP lidar data were processed in YellowScan CloudStation software integrated with Trimble POSPac UAV 9.0. Base station GNSS data were downloaded from the SP80 collecting data on site for the time the UAS was flying. 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 is set. CloudStation flight trajectories are 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 lidar point cloud (LPC), along with a strip adjustment between transect swaths using CloudStation's "robust" setting. The Cut Overlap function was applied to remove redundant points based on the closest parallel flight trajectory. The unclassified LPC model is exported from CloudStation as a 1.4 *.laz file. The LPC is brought into Global Mapper (v. 26.0) and manually cleaned of points interpreted to be noise or are above a reasonable elevation threshold based on the surrounding features. Then, the LPC is adjusted to the GCPs using a planar fit, colorized with the Ricoh orthomosaic, and exported as 2023028FA_TNB_YSMP_LPC.laz. The LPC is then gridded using maximum values and exported as a digital surface model (2023028FA_TNB_YSMP_DSM_25cm.tif). All files were exported in EPSG:6348 NAD83(2011)/UTM zone 19N and the vertical datum in EPSG:5703 NAVD88 using Geoid 18. Step completed by J. Over.

   Date: 04-Nov-2024 (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_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 section. Step completed 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:

   • https://doi.org/10.3133/ofr20211039

   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?
   The horizontal and vertical accuracy of the elevation products (2023028FA_TNB_YSMP_LPC.laz, 2023028FA_TNB_YSMP_DSM_25cm.tif, 2023028FA_TNB_Ricoh_SfM_DSM_25cm.tif, and 2023028FA_TNB_Ricoh_SfM_Ortho_5cm.tif) were assessed using the ground control points (2023028FA_TNB_AeroPoints.csv) and GPS check points (2023028FA_TNB_GPS_SP80.csv). It should also be noted that accuracy estimates of the products are for areas of bare ground or low vegetation where ground control points (GCPs) were placed or GPS points taken. Additional sources of error, such as moving objects, may cause accuracy estimates to exceed estimates in localized portions of the products. Lidar flight paths are corrected using a base station and returns over water reflect the surface, not the bottom. GPS point accuracy is assessed based on a known reference mark and a positioning solution of “FIX” for each point. The Ricoh GRII images were geotagged with estimated image locations from the SfM project, the accuracy of these estimates is assumed to be less than 1 meter.
2. How accurate are the geographic locations?
   The GCPs and GPS points have a horizontal accuracy of 3 cm. The lidar point cloud, and by association the lidar derived DSM, horizontal accuracy was assessed against positions of the AeroPoints. The horizontal accuracy is variable; based on intensity the AeroPoint centers are on average 20 cm from the known position. It is recommended that users do their own assessment for their own needs. The SfM products were spatially georeferenced using AeroPoints and created using Agisoft Metashape. The horizontal root mean square error (RMSE) of the GCPs (n=10) as reported from the Metashape project are x/y 0.009/0.011 m.
3. How accurate are the heights or depths?
   The GCPs and GPS points have a vertical accuracy of 2 cm. The lidar point cloud was assessed against the USGS 3DEP (https://www.usgs.gov/3d-elevation-program) surface in the parking lot and values fall within 10 cm. The lidar based DSM was assessed against the elevations of the AeroPoints and GPS points, and the RMSE (n=51) was 0.066 m. The SfM product vertical RMSE as reported from the Metashape project GCPs is 0.010 m.
4. Where are the gaps in the data? What is missing?
   Imagery: The YSMP camera failed to trigger during the lidar flights due to human error, thus only the Ricoh GRII images are provided. Images at take-off and landing were removed. All of these removed images can account for the non-consecutive original file names and results in a total of 588 images. A list of the images and their locations are available in 2023028FA_TNB_ImageLocations.csv. Lidar: Points were removed from the LPC in the water where they were sparse. Points identified as flying birds were also removed. LPC is not classified. Products: GeoTIFF products are cloud-optimized and deflate compressed. GPS: One AeroPoint (AP27C) did not collect data, but was surveyed with the SP80, this entry does not have internal variance values.
5. How consistent are the relationships among the observations, including topology?
   There were three UAS M600 flights and five AeroPoint GCPs. One flight was used the Ricoh GRII to take RGB photos, which produced the structure from motion (SfM) digital surface model (DSM) and orthomosaic. Two flights used the YellowScan Mapper+ (YSMP) to collect lidar data and produced the lidar point cloud (LPC) and a DSM. The SfM orthomosaic was used to color the lidar point cloud. All data fall into expected elevation ranges of a low-lying beach and dune system.

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? Aerial imaging and mapping of Town Neck Beach includes a lidar point cloud, elevation models, imagery and true-color orthomosaic, and ground control and check 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?
   • Availability in digital form:

     Data format:	2023028FA_TNB_YSMP_DSM_25cm.tif (21 MB) and 2023028FA_TNB_Ricoh_SfM_DSM_25cm.tif (27 MB) have encoded surface elevations and 2023028FA_TNB_Ricoh_SfM _Ortho_5cm.tif (320 MB) is an orthomosaic. in format GeoTIFF (version 1.0.0) Cloud optimized GeoTIFF format Adobe deflate compressed Size: 368
     Network links:	https://www.sciencebase.gov/catalog/item/67213f10d34ed0f827eaaeed https://www.sciencebase.gov/catalog/file/get/67213f10d34ed0f827eaaeed https://doi.org/10.5066/P1UBZZFA

     Data format:	The file 2023028FA_TNB_AeroPoints.csv contains ground control data, 2023028FA_TNB_GPS_SP80.csv contains GPS check points, and 2023028FA_TNB_ImageLocations.csv contains a list of the images and their positions. in format CSV (version Exported from Excel Office 365 16.01) Size: 0.1
     Network links:	https://www.sciencebase.gov/catalog/item/67213f10d34ed0f827eaaeed https://www.sciencebase.gov/catalog/file/get/67213f10d34ed0f827eaaeed https://doi.org/10.5066/P1UBZZFA

     Data format:	The Ricoh GRII images. in format JPEG (version 1.0.0) Size: 3150
     Network links:	https://www.sciencebase.gov/catalog/item/67213f10d34ed0f827eaaeed https://www.sciencebase.gov/catalog/file/get/67213f10d34ed0f827eaaeed https://doi.org/10.5066/P1GG3QSO https://doi.org/10.5066/P1UBZZFA

     Data format:	LAZ (LAserZipped) is an open file format intended for point data records. in format LAZ (version 1.4) Size: 963
     Network links:	https://www.sciencebase.gov/catalog/item/67213f10d34ed0f827eaaeed https://www.sciencebase.gov/catalog/file/get/67213f10d34ed0f827eaaeed https://doi.org/10.5066/P1UBZZFA

   • Cost to order the data: None.

Who wrote the metadata?

Dates:

Last modified: 30-Apr-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)