Lidar points, elevation models, imagery, orthomosaic, and supporting GPS data collected during UAS operations at Town Neck Beach, Sandwich, MA on June 02, 2025

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 Millo, Amit, 20260518, Lidar points, elevation models, imagery, orthomosaic, and supporting GPS data collected during UAS operations at Town Neck Beach, Sandwich, MA on June 02, 2025: 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/69f4ac22b66b0122e4360ef0

   This is part of the following larger work.
   Over, Jin-Si R., Cramer, Jennifer M., Sherwood, Christopher R., Farris, Amy S., and Millo, Amit, 2025, Topographic data, imagery, and GPS data collected during uncrewed aircraft system (UAS) operations at Town Neck Beach, Sandwich, Massachusetts (ver. 2.0, May 2026): 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:

   Suggested citation: Over, J.R., Cramer, J.M., Sherwood, C.R., Farris, A.S., and Millo, A., 2025, Topographic data, imagery, and GPS data collected during uncrewed aircraft system (UAS) operations at Town Neck Beach, Sandwich, Massachusetts (ver. 2.0, May 2026): U.S. Geological Survey data release, https://doi.org/10.5066/P1UBZZFA.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -70.48755522
   East_Bounding_Coordinate: -70.47492937
   North_Bounding_Coordinate: 41.77016595
   South_Bounding_Coordinate: 41.76226198
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/69f4ac22b66b0122e4360ef0?name=2025015FA_TNB_Jun_browse_graphic.jpg&allowOpen=true (JPEG)

   Data and products of Town Neck Beach in June 2025: Lidar point cloud, RGB image, Wingtra UAS, and orthomosaic.

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

   Calendar_Date: 02-Jun-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?

   2025015FA_TNB_MAP61_ImageryLocations.csv

   The CSV file contains the approximate position of the W1G2 images at the moment of each capture. (Source: producer defined)

   FileName

   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:	41.76285088
   Maximum:	41.76997067
   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:	-70.48698574
   Maximum:	-70.47537934
   Units:	decimal degrees

   Ellipsoid height GRS80

   Altitude of the camera at the time of each image capture relative to the NAD83(2011) reference ellipsoid GRS80. (Source: USGS)

   Range of values
   Minimum:	27.820
   Maximum:	42.446
   Units:	meters

   Easting 19N

   Post-processed interpolated X-coordinate of camera based on time of each image capture NAD83(2011)/UTM Zone 19N. (Source: USGS)

   Range of values
   Minimum:	376402.467
   Maximum:	377363.080
   Units:	meters

   Northing 19N

   Post-processed interpolated Y-coordinate of camera based on time of each image capture NAD83(2011)/UTM Zone 19N. (Source: USGS)

   Range of values
   Minimum:	4624502.105
   Maximum:	4625301.366
   Units:	meters

   Orthometric height NAVD88

   Altitude of the UAS position at the time of each image capture relative to the vertical datum NAVD88 using geoid 18. (Source: USGS)

   Range of values
   Minimum:	55.992
   Maximum:	70.629
   Units:	meters

   2025015FA_TNB_AeroPoints.csv

   Ground control point positions, elevations, and attributes (Source: USGS)

   FA

   USGS Field Activity Number (Source: USGS)

   Value	Definition
   2025-015-FA	Year, USGS ID, and Field Activity

   Date

   Calendar date of collection (Source: USGS)

   Value	Definition
   20250602	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:	41.76406053
   Maximum:	41.76821043
   Units:	decimal degrees

   Longitude NAD83(2011)

   Post-processed longitude of AeroPoint position (NAD83(2011)). (Source: USGS)

   Range of values
   Minimum:	-70.48532803
   Maximum:	-70.47829437
   Units:	decimal degrees

   Ellipsoid height GRS80

   Post-processed height in meters of AeroPoint in relation to the NAD83(2011) reference ellipsoid GRS80. (Source: USGS)

   Range of values
   Minimum:	-27.834
   Maximum:	-23.309
   Units:	meters

   Easting 19N

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

   Range of values
   Minimum:	376541.678
   Maximum:	377118.400
   Units:	meters

   Northing 19N

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

   Range of values
   Minimum:	4624636.673
   Maximum:	4625107.505
   Units:	meters

   Orthometric height NAVD88

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

   Range of values
   Minimum:	0.351
   Maximum:	4.884
   Units:	meters

   X variance (mm)

   Variance in the X-coordinate from post-processing (Source: producer defined)

   Range of values
   Minimum:	2.3
   Maximum:	6.0
   Units:	millimeters

   Y variance (mm)

   Variance in the Y-coordinate from post-processing (Source: producer defined)

   Range of values
   Minimum:	1.6
   Maximum:	6.8
   Units:	millimeters

   Z variance (mm)

   Variance in the Z-coordinate from post-processing (Source: producer defined)

   Range of values
   Minimum:	4.1
   Maximum:	10.8
   Units:	millimeters

   Baseline distance (km)

   distance of AeroPoint from nearest used processing network base station (Source: Propeller)

   Range of values
   Minimum:	0.01
   Maximum:	11.71
   Units:	kilometers

   2025015FA_TNB_GPS_Emlid_RS3_checkpoints.csv

   GPS positions, elevations, and attributes (Source: USGS)

   FA

   USGS Field Activity Number (Source: USGS)

   Value	Definition
   2025-015-FA	Year, USGS ID, and Field Activity

   Date

   Calendar date of collection (Source: USGS)

   Value	Definition
   20250602	YYYYMMDD

   Point ID

   Unique point identification number. NaN assigned to reference point pre-loaded into project. (Source: Processor defined)

   Range of values
   Minimum:	0
   Maximum:	99

   Attributes

   Identifier for GPS check shots. Big belly-OPUS refers to the known solution of the reference mark at Town Neck Beach, big belly-Open refers to a stake out check in on the reference mark, AP-### refers to a surveyed AeroPoint, and 'check point' refers to a shot taken on the ground. (Source: producer defined) Character string.

   Latitude NAD83(2011)

   RTK x position of the point relative to (NAD83(2011)). (Source: USGS)

   Range of values
   Minimum:	41.76443611
   Maximum:	41.76859043
   Units:	decimal degrees

   Longitude NAD83(2011)

   RTK y position of the point relative to (NAD83(2011)). (Source: USGS)

   Range of values
   Minimum:	-70.48566453
   Maximum:	-70.47934698
   Units:	decimal degrees

   Ellipsoid height

   RTK z position of the point relative to the NAD83(2011) reference ellipsoid GRS80. (Source: USGS)

   Range of values
   Minimum:	-29.489
   Maximum:	-21.762
   Units:	meters

   Easting 19N

   RTK x position of the point relative to NAD83(2011)/UTM Zone 19N. (Source: USGS)

   Range of values
   Minimum:	376513.49
   Maximum:	377031.618
   Units:	meters

   Northing 19N

   RTK y position of the point relative to NAD83(2011)/UTM Zone 19N. (Source: USGS)

   Range of values
   Minimum:	4624679.878
   Maximum:	4625147.183
   Units:	meters

   Orthometric height NAVD88

   RTK z position of the point relative to NAVD88 with GEOID 18 applied. (Source: USGS)

   Range of values
   Minimum:	-1.300
   Maximum:	6.427
   Units:	meters

   Tilt angle

   Angle to nadir of the Emlid RS3 (Source: USGS)

   Range of values
   Minimum:	0.0
   Maximum:	10.1
   Units:	degrees

   Elevation RMS

   Root mean square in the Z-coordinate (Source: producer defined)

   Range of values
   Minimum:	0.015
   Maximum:	0.020
   Units:	meters

   Lateral RMS

   Root mean square in the horizontal XY-coordinate (Source: producer defined)

   Range of values
   Minimum:	0.010
   Maximum:	0.022
   Units:	meters

   2025015FA_TNB_WLDR_LPC.laz

   UAS lidar point cloud in *.laz v. 1.4 file format. This georeferenced point cloud was colorized using natural color RGB image values and is not classified. There are 30,711,943 points. Point density is 138.43 points per square meter and point spacing is 0.085 m. (Source: producer defined)

   Elevation

   Surface elevation in EPSG:5703 using GEOID 18. (Source: Wingtra)

   Range of values
   Minimum:	-1.435
   Maximum:	13.998
   Units:	meters

   Classification

   Each lidar point has a classification value assigned to it according to the ASPRS LAS Specification. (Source: Global Mapper)

   Value	Definition
   0	Data have not been classified.

   Intensity

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

   Range of values
   Minimum:	0
   Maximum:	255

   Return number

   Return number. Each laser pulse can produce multiple discrete observations as emitted light is reflected by objects in the scene. (Source: Wingtra)

   Range of values
   Minimum:	1
   Maximum:	3

   Scan angle

   The scan angle of the laser beam that produced each point where 0 degrees indicates nadir. (Source: Wingtra)

   Range of values
   Minimum:	-43
   Maximum:	44
   Units:	Degrees

   2025015FA_TNB_WLDR_DSM_25cm.tif

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

   Value

   Surface elevation in EPSG:5703 using GEOID 18. No-data value is set to –32767. (Source: producer defined)

   Range of values
   Minimum:	-1.426
   Maximum:	13.998
   Units:	meters

   2025015FA_TNB_MAP61_SfM_Ortho_5cm.tif

   Cloud-optimized JPEG compressed true-color orthomosaic. No data is represented by 0 in the Alpha band. (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

   Band_4

   Alpha band. 0 is no data, 255 is data. (Source: Agisoft Metashape)

   Range of values
   Minimum:	0
   Maximum:	255

   Entity_and_Attribute_Overview:

   The filenames are formatted as "2025015FA_TNB_sensor/product_resolution.*** ", where 2025015 is the USGS Field activity ID, location is Town Neck Beach (TNB), sensor is MAP61, AeroPoints, Emlid RS3, and products include orthomosaic (Ortho), digital surface model (DSM), and lidar point cloud (LPC).

   Entity_and_Attribute_Detail_Citation: USGS Field Activity 2025-015-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
   • Amit Millo
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 x2310 (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: 02-Jun-2025 (process 1 of 5)

   GROUND CONTROL: Ten AeroPoint GCPs were spaced out over the field site and left on for at least 30 minutes to collect GNSS data. After collection, the AeroPoint data were uploaded via a Wi-Fi connection and run through a post-processing kinematic algorithm of the propeller 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 2025015FA_TNB_AeroPoints.csv. An Emlid RS2+ was set up as a base station using an 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 on the parking lot, beach, and AeroPoints, data were provided in 2025015FA_TNB_GPS_Emlid_RS3_checkpoints.csv.
   UAS FLIGHTS: The lidar sensor was a 905 nm wavelength Hesai XT32-M2X with a 90 / 40.3 degree horizontal and vertical field of view (FOV). It is a rotating sensor, generating up to three returns with an effective point rate for a single return of 160k pts/s. The camera module uses the Wingtra MAP61 61-megapixel (MP) camera with a 17 mm lens. The system uses a NovAtel OEM7500 multi-frequency, high precision GNSS receiver. The lidar data was saved to the 256 GB thumb drive in five different *.data files. The RGB images are saved as *.JPG files. The lidar data were collected with the Wingtra UAS flying 61 meters above ground level with northwest-southeast transect passes. The camera module was set to take images every 2 seconds. After the flights the lidar and RGB data were downloaded off their respective sensor. Note, the geotagged positions embedded in the imagery Exif information were in EPSG:4326, this is the only option in the software. The positions were converted to EPSG:6348 and EPSG:5703 in the imagery locations file (2025015FA_TNB_MAP61_ImageryLocations.csv) and were accounted for when transforming to EPSG:6348 and EPSG:5703 in the products.

   Date: 10-Jul-2025 (process 2 of 5)

   RAW IMAGERY: The W1G2 images were geotagged in WingtraHub using the base station RINEX file and OPUS corrected location of the base. 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 to avoid any possibility of duplicate names. These steps are described here. 1. ExifTool was used to tag each photo 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 '2025015FA_f01MAP61_20250602T165822Z_#####', 2025015FA is the field activity ID; f01 is the flight number; MAP61 is camera used; 20250601 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 ##### is the original raw photo suffix appended to the end of the new filename. 3. Images are validated and uploaded onto the Imagery Data System.

   Date: 10-Jul-2025 (process 3 of 5)

   PHOTOGRAMMETRY: The ortho product was created in Agisoft Metashape v. 2.2.0 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 along with a csv file containing the following information about the camera when the image was taken: latitude/longitude (WGS84), ellipsoid altitude (m), vertical and horizontal accuracy (m), omega/phi/kappa (°), and accuracy (°). 2. Photos were aligned at a high accuracy 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 PPK geotagged image locations. 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 10, 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 (2025015FA_TNB_MAP61_SfM_Ortho_5cm.tif). Step processed by J. Over.

   Date: 11-Jul-2025 (process 4 of 5)

   LiDAR DATA: The lidar data were processed in the Wingtra LIDAR app. The .data files were uploaded into the app along with the base station RINEX *.25O file. The OPUS corrected location of the base and the ARP-APC offset were then entered manually. After the processing was complete, the start and end location of each transect was manually identified to clip the paths and remove points obtained when the aircraft was turning. This point cloud product was exported from the Wingtra LIDAR app and was brought into Global Mapper (GM) and manually cleaned of points interpreted to be noise or water. The LPC was colorized in GM with the SfM orthomosaic. Then, the LPC was gridded at 25 cm 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 2025015FA_TNB_WLDR_DSM_25cm.tif. The LPC was exported as 2025015FA_TNB_WLDR_LPC.laz. All files were exported in EPSG:6348 and EPSG:5703 using GEOID 18.

   Date: 11-Jul-2025 (process 5 of 5)

   CLOUD OPTIMIZATION: The DSM was Deflate compressed 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.
   The orthomosaic was JPEG compressed and turned into a cog using gdal_translate with the following command: for %i in (.\*.tif) do gdal_translate %i .\%~ni_cog.tif -of COG -stats -co BLOCKSIZE=256 -co COMPRESS=JPEG -co QUALITY=90 -co PREDICTOR=YES -co NUM_THREADS=ALL_CPUS -co BIGTIFF=YES 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 x2310 (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?
   GPS: The theoretical internal accuracy of the Emlid RS3 is 2 cm. Points were assumed to be within that tolerance after staking out at known reference mark “big belly” and the values were within 2 cm. The vertical and horizontal root mean square (RMS) internal variances for each point were also reported in 2025015FA_TNB_GPS_Emlid_RS3_checkpoints.csv, values should be less than 2 cm. The AeroPoint2 ground control points (GCPs), referred to as just AeroPoints from here on, have an internal reported variance provided in 2025015FA_TNB_AeroPoints.csv, the global accuracy was calculated and reported below by adding the variance to twice the longest baseline distance. Two AeroPoints were also surveyed by the RS3.
   GeoTIFFs: The horizontal and vertical accuracy of the products (2025015FA_TNB_WLDR_DSM_25cm.tif and 2025015FA_TNB_MAP61_SfM_Ortho_5cm.tif) were assessed using the AeroPoints 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 (2025015FA_TNB_WLDR_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 LPC was colorized from the SfM orthomosaic. Some misalignment in the collected lidar strips may occur. Lidar does not pass through water. Gaps may also exist where there is less scan overlap and point densities were lower. Users are advised to evaluate the data for their own needs.
2. How accurate are the geographic locations?
   Images: The Wingtra Map61 images were geotagged in WingtraHub v. 2.18.0 using base station data and had an average xy accuracy of 0.03 m.
   GPS: Emlid RS3 GPS points have a xy RMS (precision) average of 1.7 cm. AeroPoint 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 AeroPoints in the lidar intensity view (not the RGB). The horizontal accuracy is variable and within 10 cm.
   SfM: The orthomosaic was spatially georeferenced using AeroPoint 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 MAP61 images were geotagged in WingtraHub v. 2.18.0 using the base station data and had an average z accuracy of 0.04 m. GPS: Emlid RS3 GPS points have a z RMS (precision) average of 1.8 cm. AeroPoint global vertical accuracy is 3.5 cm.
   Lidar: The LPC was assessed against the elevations of the AeroPoints and GPS check points: the RMSE (n=74) was 0.05 m.
4. Where are the gaps in the data? What is missing?
   Imagery: The MAP61 camera triggered every 2 seconds. Images not at the mapping altitude were removed and account for a total of 540 MAP61 images. Products: GeoTIFF products are cloud-optimized and Deflate compressed. The LPC has been cleaned in Global Mapper to remove water points and wave noise.
5. How consistent are the relationships among the observations, including topology?
   There were three UAS flights and ten AeroPoint. Flight one (16 min) used the MAP61 camera module on the WingtraOne Gen II (W1G2) to collect RGB images. Flight two (13 min) used the same MAP61 camera on the W1G2 and was performed to finish surveying the coastline as some of the shore was missed on the first flight. These two flights were used to generate the orthomosaic. Flight three (12 min) collected lidar data (WLDR) and produced the lidar point cloud (LPC) and digital surface model (DSM). An Emlid RS2+ was set up as a base station and an Emlid RS3 GPS unit was used to collect check points.

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 the imagery (MAP61), orthomosaic, the Wingtra lidar point cloud, digital surface model, Emlid GPS check points, and AeroPoint 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?
   • Availability in digital form:

     Data format:	2025015FA_TNB_WLDR_DSM_25cm.tif (15 MB Deflate compressed) is an elevation model and 2025015FA_TNB_MAP61_SfM_Ortho_5cm.tif (67 MB JPEG compressed) is an orthomosaic. in format GeoTIFF (version 1.0.0) Cloud optimized GeoTIFF format Size: 80
     Network links:	https://www.sciencebase.gov/catalog/item/69f4ac22b66b0122e4360ef0 https://www.sciencebase.gov/catalog/file/get/69f4ac22b66b0122e4360ef0 https://doi.org/10.5066/P1UBZZFA

     Data format:	The CSV file 2025015FA_TNB_AeroPoints.csv contains ground control data, 2025015FA_TNB_GPS_Emlid_RS3_checkpoints.csv contains GPS check points, and 2025015FA_TNB_MAP61_ImageryLocations.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/69f4ac22b66b0122e4360ef0 https://www.sciencebase.gov/catalog/file/get/69f4ac22b66b0122e4360ef0 https://doi.org/10.5066/P1UBZZFA

     Data format:	The MAP61 images. in format JPEG (version 1.0.0) Size: 2180
     Network links:	https://www.sciencebase.gov/catalog/item/69f4ac22b66b0122e4360ef0 https://www.sciencebase.gov/catalog/file/get/69f4ac22b66b0122e4360ef0 https://doi.org/10.5066/P1UBZZFA https://doi.org/10.5066/P1GG3QSO

     Data format:	LAZ (LAserZipped) is an open file format intended for point data records. in format LAZ (version 1.4) Size: 260
     Network links:	https://www.sciencebase.gov/catalog/item/69f4ac22b66b0122e4360ef0 https://www.sciencebase.gov/catalog/file/get/69f4ac22b66b0122e4360ef0 https://doi.org/10.5066/P1UBZZFA

   • Cost to order the data: None.

Who wrote the metadata?

Dates:

Last modified: 18-May-2026

Metadata author:

Jin-Si R. Over

U.S. Geological Survey, Northeast Region

Geographer

U.S. Geological Survey

Woods Hole, MA

508-548-8700 x2310 (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)