Lidar point cloud, elevation models, GPS data, and imagery and orthomosaics from thermal, true-color, and multispectral aerial imagery, collected during UAS operations at Marsh Island, New Bedford, MA on July 23, 2025

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Frequently anticipated questions:

What does this data set describe?

Title:
Lidar point cloud, elevation models, GPS data, and imagery and orthomosaics from thermal, true-color, and multispectral aerial imagery, collected during UAS operations at Marsh Island, New Bedford, MA on July 23, 2025
Abstract:
Small Uncrewed Aircraft Systems (sUAS) were used to collect aerial remote sensing data over Marsh Island, a salt marsh restoration site along New Bedford Harbor, Massachusetts. Remediation of the site will involve direct hydrological and geochemical monitoring of the system alongside the UAS remote sensing data. On July 23rd, 2025, USGS personnel collected natural (RGB) color images, multispectral images, thermal images, lidar, and ground control points. These data were processed to produce a high-resolution lidar point cloud (LPC), digital elevation models (surface and terrain), and natural color, multispectral, and thermal orthomosaics. Data collection is related to USGS Field Activity 2025-009-FA and this release only provides the UAS portion.
Supplemental_Information:
For more information about the WHCMSC Field Activity, see https://cmgds.marine.usgs.gov/services/activity.php?fan=2025-009-FA. Images can be viewed or downloaded on the USGS Imagery Data System (IDS) here https://doi.org/10.5066/P14MGKBY in the collections 2025_MI_Jul_YSMP, 2025_MI_Jul_SX10r, 2025_MI_Jul_aPT. 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., Millo, Amit, Cramer, Jennifer M., Ackerman, Seth D., and Brosnahan, Sandra M., 2026, Lidar point cloud, elevation models, GPS data, and imagery and orthomosaics from thermal, true-color, and multispectral aerial imagery, collected during UAS operations at Marsh Island, New Bedford, MA on July 23, 2025: data release DOI:10.5066/P19TLXVG, 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., Cramer, Jennifer M., Millo, Amit, Brosnahan, Sandra M., Ackerman, Seth D., and Ganju, Neil Kamal, 2024, Topographic, multispectral, and GPS data collected during uncrewed aircraft system (UAS) operations at Marsh Island, New Bedford, Massachusetts (ver. 2.0, May 2026): data release DOI:10.5066/P19TLXVG, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Over, J.R., Cramer, J.M., Millo, A., Brosnahan, S.M., Ackerman, S.D., and Ganju, N.K., 2024, Topographic, multispectral, and GPS data collected during uncrewed aircraft system (UAS) operations at Marsh Island, New Bedford, Massachusetts (ver. 2.0, May 2026): U.S. Geological Survey data release, https://doi.org/10.5066/P19TLXVG.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.91864516
    East_Bounding_Coordinate: -70.91323912
    North_Bounding_Coordinate: 41.65363357
    South_Bounding_Coordinate: 41.65076909
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/695fe430d4be024e3af50562?name=2025009FA_MI_Jul_data_browse.jpg&allowOpen=true (JPEG)
    Data and products of Marsh Island: RGB, thermal, and multispectral images, lidar point cloud, ortho, digital surface model (DSM), and digital terrain model (DTM).
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 23-Jul-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?
    2025009FA_MI_Jul_ImageLocations.csv
    The CSV file contains the approximate position of the YSMP, SX10, and aPT images at the moment of each capture. Note that each set (1-6) of aPT images has the same position. (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 in UTC time. (Source: Processor defined) Character string.
    Latitude NAD83[2011]
    Latitude (x-coordinate) of camera based on time of each image capture. Positive values represent North coordinates. (Source: USGS)
    Range of values
    Minimum:41.65094312
    Maximum:41.65324746
    Units:decimal degrees
    Longitude NAD83[2011]
    Longitude (y-coordinate) of camera based on time of each image capture. Negative values represent West coordinates. (Source: USGS)
    Range of values
    Minimum:-70.91832778
    Maximum:-70.91389167
    Units:decimal degrees
    Altitude NAD83[2011] ellipsoid
    Altitude of the camera position at the time of each image capture relative to the NAD83(2011) GRS80 ellipsoid. (Source: Processor defined)
    Range of values
    Minimum:3.400
    Maximum:75.400
    Units:meters
    Northing 19N
    Y-coordinate of camera in NAD83(2011)/UTM Zone 19N. (Source: USGS)
    Range of values
    Minimum:4612797.876
    Maximum:4613052.712
    Units:meters
    Easting 19N
    X-coordinate of camera in NAD83(2011)/UTM Zone 19N. (Source: USGS)
    Range of values
    Minimum:340261.148
    Maximum:340631.805
    Units:meters
    Altitude NAVD88
    Altitude of the camera position at the time of each image capture relative to NAVD88 with GEOID 18 applied. (Source: USGS)
    Range of values
    Minimum:32.562
    Maximum:104.564
    Units:meters
    2025009FA_MI_Jul_AeroPoints.csv
    Ground control point positions, elevations, and attributes (Source: USGS)
    FA
    USGS Field Activity Number (Source: USGS)
    ValueDefinition
    2025-009-FAYear, USGS ID, and Field Activity
    Date
    Calendar date of collection (Source: USGS)
    ValueDefinition
    20250723YYYYMMDD
    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 (x-coordinate) of AeroPoint position (NAD83[2011]). (Source: USGS)
    Range of values
    Minimum:41.65125921
    Maximum:41.65231674
    Units:decimal degrees
    Longitude NAD83[2011]
    Post-processed longitude (y-coordinate) of AeroPoint position (NAD83[2011]). Negative values represent West coordinates. (Source: USGS)
    Range of values
    Minimum:-70.91790236
    Maximum:-70.91425296
    Units:decimal degrees
    Ellipsoid height GRS80
    Post-processed height in meters of AeroPoint in relation to the NAD83(2011) reference GRS80 ellipsoid. (Source: USGS)
    Range of values
    Minimum:-28.708
    Maximum:-25.873
    Units:meters
    Northing 19N
    Post-processed interpolated Y-coordinate of AeroPoint in NAD83(2011)/UTM Zone 19N. (Source: USGS)
    Range of values
    Minimum:4612828.194
    Maximum:4612948.085
    Units:meters
    Easting 19N
    Post-processed interpolated X-coordinate of AeroPoint in NAD83(2011)/UTM Zone 19N. (Source: USGS)
    Range of values
    Minimum:340296.464
    Maximum:340602.241
    Units:meters
    Orthometric height NAVD88
    Post-processed Z-coordinate of AeroPoint using NAVD88 with GEOID 18 applied. (Source: USGS)
    Range of values
    Minimum:0.461
    Maximum:3.296
    Units:meters
    Xvar mm
    Variance in the X-coordinate from post-processing (Source: producer defined)
    Range of values
    Minimum:7.9
    Maximum:19.8
    Units:millimeters
    Yvar mm
    Variance in the Y-coordinate from post-processing (Source: producer defined)
    Range of values
    Minimum:5.2
    Maximum:15.7
    Units:millimeters
    Zvar mm
    Variance in the Z-coordinate from post-processing (Source: producer defined)
    Range of values
    Minimum:8.3
    Maximum:19.8
    Units:millimeters
    Baseline distance km
    distance of AeroPoint from nearest used processing network base station (Source: Propeller)
    Range of values
    Minimum:9.28
    Maximum:9.59
    Units:kilometers
    2025009FA_MI_Jul_GPS_Emlid_RS3.csv
    GPS check point shots, elevations, and errors (Source: USGS)
    FA
    USGS Field Activity Number (Source: USGS)
    ValueDefinition
    2025-009-FAYear, USGS ID, and Field Activity
    Date
    Calendar date of collection (Source: USGS)
    ValueDefinition
    20250723YYYYMMDD
    Point ID
    Unique point identification number. (Source: Processor defined)
    Range of values
    Minimum:1
    Maximum:184
    Attributes
    Type of GPS point; “checkshots” refers to points on the ground. (Source: producer defined) Character string.
    Latitude NAD83[2011]
    RTK latitude (x-coordinate) of GPS position (NAD83[2011]). (Source: USGS)
    Range of values
    Minimum:41.65066772
    Maximum:41.65252161
    Units:decimal degrees
    Longitude NAD83[2011]
    RTK longitude (y-coordinate) of GPS position (NAD83[2011]). (Source: USGS)
    Range of values
    Minimum:-70.91783477
    Maximum:-70.91420082
    Units:decimal degrees
    Ellipsoid height GRS80
    Height in meters of GPS point in relation to the NAD83(2011) reference ellipsoid GRS80. (Source: USGS)
    Range of values
    Minimum:-28.281
    Maximum:-25.274
    Units:meters
    Northing 19N
    Y-coordinate of GPS point in NAD83(2011)/UTM Zone 19N. (Source: USGS)
    Range of values
    Minimum:4612763.470
    Maximum:4612971.668
    Units:meters
    Easting 19N
    X-coordinate of GPS point in NAD83(2011)/UTM Zone 19N. (Source: USGS)
    Range of values
    Minimum:340302.261
    Maximum:340606.409
    Units:meters
    Orthometric height NAVD88
    Z-coordinate of GPS point in relation to NAVD88 with GEOID 18 applied. (Source: USGS)
    Range of values
    Minimum:0.882
    Maximum:3.893
    Units:meters
    Tilt angle
    Angle of GPS pole from nadir (Source: producer defined)
    Range of values
    Minimum:0.2
    Maximum:32.7
    Units:degrees
    Elevation RMS
    Root mean square internal precision value in the z-direction. (Source: producer defined)
    Range of values
    Minimum:0.010
    Maximum:0.021
    Units:meters
    Lateral RMS
    Root mean square internal precision value in the x and y-direction. (Source: producer defined)
    Range of values
    Minimum:0.016
    Maximum:0.022
    Units:meters
    2025009FA_MI_Jul_YSMP_LPC_classified.laz
    UAS lidar point cloud in .LAZ file format. This georeferenced point cloud was colorized using natural color RGB image values and is classified with ground and unclassified points. There are 29,133,519 points, the point density is 554 points per square meter, and point spacing is 0.0425 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:-0.73
    Maximum:27.010
    Units:meters
    Classification
    Each lidar point has a classification value assigned to it according to the ASPRS LAS Specification. (Source: Global Mapper)
    ValueDefinition
    1Data have been subjected to a classification algorithm but emerged in an unclassifed state.
    2 (Ground)Data have been subjected to a classification algorithm and identified as bare ground.
    7 (Low Point)Data have been subjected to a classification algorithm and identified as low point noise.
    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:65025
    Return number
    Return number. Each laser pulse can produce multiple discrete observations as emitted light is reflected by objects in the scene. (Source: YellowScan CloudStation)
    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: YellowScan CloudStation)
    Range of values
    Minimum:-41
    Maximum:45
    Units:Degrees
    2025009FA_MI_Jul_YSMP_DSM_10cm.tif
    A cloud-optimized digital surface model created from the maximum values of the lidar point cloud with encoded elevation values. Raster resolution is 10 cm. (Source: USGS)
    Value
    Surface elevation orthometric height NAVD88 (m) using Geoid 2018 in NAD83(2011) UTM Zone 19N. No-data value is –3.4028e+38. (Source: producer defined)
    Range of values
    Minimum:-0.722
    Maximum:26.840
    Units:meters
    2025009FA_MI_Jul_YSMP_DTM_10cm.tif
    A cloud-optimized digital terrain model created from the ground points of the classified lidar point cloud with encoded elevation values. Raster resolution is 10 cm. (Source: USGS)
    Value
    Surface elevation orthometric height NAVD88 (m) using Geoid 2018 in NAD83(2011) UTM Zone 19N. No-data value is –3.4028e+38. (Source: producer defined)
    Range of values
    Minimum:-0.722
    Maximum:7.470
    Units:meters
    2025009FA_MI_Jul_YSMP_Ortho_5cm.tif
    True-color (RGB) cloud optimized GeoTIFF of Marsh Island created from YSMP images using structure from motion. (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
    2025009FA_MI_Jul_aPT_5BandOrtho_5cm.tif
    Pansharpened multispectral (B, G, R, Re, NIR) cloud optimized GeoTIFF of Marsh Island. Values have been transformed from digital numbers into reflectance values (unitless). No-data value is -32767. (Source: producer defined)
    Band_1
    Blue wavelength band reflectance (Source: Agisoft Metashape)
    Range of values
    Minimum:-0.040
    Maximum:2.789
    Units:reflectance
    Band_2
    Green wavelength band reflectance (Source: Agisoft Metashape)
    Range of values
    Minimum:-0.022
    Maximum:2.193
    Units:reflectance
    Band_3
    Red wavelength band reflectance (Source: Agisoft Metashape)
    Range of values
    Minimum:0.000
    Maximum:2.016
    Units:reflectance
    Band_4
    Red-edge wavelength band reflectance (Source: Agisoft Metashape)
    Range of values
    Minimum:-0.016
    Maximum:2.609
    Units:reflectance
    Band_5
    Near infrared wavelength band reflectance (Source: Agisoft Metashape)
    Range of values
    Minimum:-0.005
    Maximum:3.776
    Units:reflectance
    2025009FA_MI_Jul_SX10r_Ortho_5cm.tif
    Thermal infrared (IR) cloud optimized GeoTIFF of Marsh Island. (Source: USGS)
    Band_1
    Thermal infrared band (Source: Agisoft Metashape)
    Range of values
    Minimum:17.463
    Maximum:67.961
    Units:Celsius
    Entity_and_Attribute_Overview:
    The filenames are formatted as "2025009FA_MI_Jul_sensor/product_resolution.*** ", where 2025009FA is the USGS Field activity ID, location is Marsh Island (MI), Jul is the month July, sensor is either YSMP, aPT, SX10, Emlid RS3, or AeroPoint and products include orthomosaics (Ortho), digital surface and terrain models (DSM and DTM), lidar point cloud (LPC), a list of all the images, and GPS checkpoints. Product resolution is in cm if applicable. The horizontal coordinate reference system for all products is NAD83(2011)/UTM19N, the vertical coordinate reference system is NAVD88. *** is the file extension. The horizontal coordinate reference system for all products is NAD83(2011)/UTM19N and the vertical coordinate reference system is NAVD88.
    Entity_and_Attribute_Detail_Citation: USGS Field Activity 2025-009-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
    • Jennifer M. Cramer
    • Seth D. Ackerman
    • 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 x2310 (voice)
    jover@usgs.gov

Why was the data set created?

The elevation and imagery products were produced to help the site’s conservation partnership evaluate the baseline conditions of the site, with future data collections planned to monitor landscape change from remediation efforts and potential 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: 23-Jul-2025 (process 1 of 6)
    GROUND CONTROL: Ten AeroPoint GCPs, occasionally on top of larger black and white reflective tarps, were spaced out over the field site and left on for at least one hour to collect Global Navigation Satellite System (GNSS) data. After collection and connected to Wifi, the AeroPoint data were uploaded and run through a post-processing kinematic algorithm of the Propeller network to get a global accuracy. Internal accuracy is reported in xyz variance and with a baseline distance. The data were exported in the horizontal datum NAD83(2011) to produce latitude, longitude, and ellipsoid heights, and then UTM19N and vertical datum NAVD88 using GEOID 18 was used to produce easting and northing and orthometric heights. These were exported to a CSV file and named 2025009FA_MI_Jul_AeroPoints.csv.
    Date: 23-Jul-2025 (process 2 of 6)
    UAS FLIGHTS: The lidar sensor is 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 non-repetitive scan pattern, which moves the sensor in spirograph (flower) motion and is optimal for vegetated areas as it can capture more angles by surveying in front and behind the sensor. The camera module is 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 is saved to a 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 are saved to a micro SD card as *.JPG files. A configuration text file (CONFIG.TXT) is 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 aPT has 7 sensors with global shutters: 5 multispectral bands, blue (443-507 nm), green (533-587 nm), red (652-684 nm), red edge (705-729 nm), and near-infrared (NIR) (785-899 nm), 1 panchromatic band (171.5 nm - 1098 nm), and 1 long-wave infrared (LWIR) thermal band (4.5 - 16.5 microns). The LWIR band images were not used in any processing workflows and were excluded from this data release. The multispectral bands have a focal length of 8 mm and acquire images at 3.2 megapixels, 2064 x 1544 pixel resolution, and a 12-bit depth. The panchromatic band has a focal length of 16.3 mm and acquires images at 12 megapixels, 4112 x 3008 pixel resolution, and 12-bit depth. The sensor apertures are f/1.8 for the spectral bands and f/4.5 for the panchromatic band. Sensor properties are automatically written to the image exif. Images are saved to a CF Express type B SD card in TIFF format. *Note that because most 3rd-party software supports 16-bit images, the 12-bit images are output to TIFF files in a 16-bit container with the last four bits filled with zeros.
    Both sensors (YSMP and aPT) were attached to a DJI Matrice 600 Pro UAS with approved government edition firmware. Two 1x1 m Group 8 Technology reflectance calibration tarps with reflectance values of 0.48 and 0.12 were staked out within the UAS survey area for validation of post-processed aPT reflectance products.
    The YSMP lidar data was collected with the UAS flying at 7 m/s at 68 meters above ground level with north-south transect passes. The scan method was set to repetitive. The camera module was set to take images every 2 seconds. After the flight the lidar data were taken off the sensor.
    The aPT data was collected with the UAS flying at 8 m/s at 48 meters above ground level with east-west transect passes that achieve ~80% forelap and sidelap. Image sets were taken every 2 seconds. The aPT received power from a connection to the UAS. The downwelling light sensor was attached and measured ambient light for each of the spectral bands captured by the camera. For each camera shutter trigger, camera settings (focal length, ISO, etc), spectral irradiance, roll, pitch, yaw, gain, exposure time, and GPS position data were automatically incorporated into the Exif data for each image. Just prior to takeoff and after landing, a Micasense calibration panel (RP06-2224002-OB) was placed under the camera for several seconds to capture calibration images. After the flight, the UAS was powered off, the SD card was removed, and all images and files relating to the survey were downloaded to a field computer.
    The Skydio X10 is a small UAS with an integrated VT300-L camera system. The radiometric thermal camera is a FLIR Boson+ with less than 30 millikelvin sensitivity. The Skydio X10 also has two RGB cameras, one has a 50 degree field of view (narrow) and the other has a 93 degree field of view (wide). A single flight in auto mapping mode was flown at 60 meters with 70% desired sidelap and overlap and 1.21 cm ground sampling distance. The UAS was flown at 5 m/s using the wide camera and thermal camera. An RGB photo dataset and two sets of thermal images are taken, but only the set with the radiometric data (SX10r) is provided, as the other two sets are redundant for the project.
    Note, the YSMP, aPT, and SX10 geotagged positions embedded in the imagery have been converted in Metashape to NAD83(2011) and NAVD88 geoid 18 and are provided in the imagery locations file (2025009FA_MI_Jul_ImageryLocations.csv) and is accounted for when transforming to NAD83(2011)/UTM19N and NAVD88 Geoid 18 in the SfM products.
    Date: 06-Apr-2026 (process 3 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 Emlid RS2+ 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 and calibrated on 2023-09-26 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 xyz arm offsets (0.000, -0.118, -0.490) and boresight angle corrections were applied to the LPC, along with a strip adjustment between transect swaths using CloudStation's "robust" setting. The LPC was colored by the YSMP camera based on the photo timestamp. The “Cut Overlap” function was run. The LPC was classified using CloudStation settings: The LPC was exported as a zipped laz file (ver. 1.4) and opened in Global Mapper (ver. 26.0) where points were cleaned and shifted vertically with a best fit plane to fit the AeroPoint GCPs (fixed Z shift of 0.1422 m). The DSM was exported using maximum values of all LPC points (2025009FA_MI_Jul_YSMP_DSM_10cm.tif) and a DTM was exported using the minimum values of just the LPC points classified as ground (2025009FA_MI_Jul_YSMP_DSM_10cm.tif). All files were exported in EPSG:6348 (NAD83(2011)/UTM zone 19N and the vertical datum in EPSG:5703 (NAVD88 height in meters). This processing was done in January of 2026. After review, it was deemed that the vertical EPSG was not correct in the laz file. It was loaded into Metashape and re-exported into the correct datum on April 6, 2026. This did not affect the DSM or DTM products.
    Date: 23-Jan-2026 (process 4 of 6)
    RAW IMAGERY: The YSMP images were geotagged in Emlid Studio using the lidar *.T04 file and Emlid RS2+ base RINEX files. The YSMP, SX10, and aPT 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 2.2) to avoid any possibility of duplicate names. These steps are described here. Note that for the aPT images the commands use *.tif instead of *.JPG. 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 '2025009FA_f01YSMP_20250723T174254Z_DSC####', 2025009FA is the field activity ID, f01 is the flight number, YSMP is the camera on the YellowScan Mapper Plus, 20250723 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 DSC#### is the original raw photo name appended to the end of the new filename.
    Date: 24-Jan-2026 (process 5 of 6)
    PHOTOGRAMMETRY: The three ortho products were 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, https://support.micasense.com/hc/en-us/articles/4416696717847-Pan-sharpening-processing-data-from-Altum-PT-and-RedEdge-P-cameras-in-Agisoft-Metashape for processing the aPT images, and https://support.skydio.com/hc/en-us/articles/27236378437019-Scan-reconstruction-best-practices-with-Skydio-X10 for processing the SX10 images): 1. For each image type (SX10r, YSMP, aPT) a project was created and imagery was imported (as a multi-camera system for SX10r and the aPT images). 2. Photos were aligned at a low accuracy and then GCPs were automatically detected in the point cloud. For the aPT images, the Panchromatic band images were used to identify tie points. GCP positions (2025009FA_MI_Jul_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 3, and three iterations of the 'Reprojection accuracy' filter to get to a level of 1. 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, for each project multiple ‘chunks’ were created so that independent high quality dense clouds with a low-frequency filtering algorithm could be made. The dense point clouds were then edited by visual inspection 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 YSMP orthomosaic is a 3-band orthomosaic exported at 5 cm resolution (2025009FA_MI_Jul_YSMP_Ortho_5cm.tif). The SX10r orthomosaic is single-band (IR), the values are converted from Kelvin to Celsius using the band math (0.01*thermal_band)-273.15 and exported at 5 cm resolution (2025009FA_MI_Jul_SX10_Ortho_5cm.tif). The aPT ortho product was pansharpened and transformed so that the bands were all divided by the reflectance normalization factor 32768 (half of the available digital number range or 100% reflectance for each band for 16-bit images). The normalization process produces values that are a unitless reflectance value between 0 and 1, where 1 would be 100% reflectance, i.e. lighter. This 5-band product was exported at 5 cm resolution (2025009FA_MI_Jul_aPT_5BandOrtho_5cm.tif). Processing of the SX10 and aPT done by J. Cramer. Processing of the YSMP images done by A. Millo.
    Date: 27-Jan-2026 (process 6 of 6)
    CLOUD OPTIMIZATION: The aPT and SX10 ortho, DSM, and DTM geoTIFF products were DEFLATE compressed and turned into 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. The YSMP ortho product was JPEG compressed and cloud optimized using the 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 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. GPS check points with the RS3 that had a Real Time Kinematic (RTK) ‘FIX’ were assumed to be within that tolerance after staking out at known reference mark BBNEP-2023-1 and the values were within 2 cm. The vertical and horizontal root mean square (RMS) internal variance for each point were also reported in 2025009FA_MI_Jul_GPS_Emlid_RS3_checkpoints.csv, values should be less than 2 cm. The ground control points (GCPs) used were Propeller AeroPoint 2s, referred to as just AeroPoints from here on, which have an internal reported variance provided in 2025009FA_MI_Jul_AeroPoints.csv, their global accuracy was calculated and reported below by adding the variance to twice the longest baseline distance.
    Images: The three types of imagery are all geotagged with position information and various sensor data. Position accuracies are embedded in the EXIF data of the thermal and multispectral images from the integrated GPS. RGB images were geotagged using Post Processing Kinematic (PPK) data from the base station and the YellowScan Mapper Plus (YSMP).
    GeoTIFFs: The horizontal and vertical accuracy of the products (2025009FA_MI_Jul_YSMP_DSM_10cm.tif, 2025009FA_MI_Jul_YSMP_DTM_10cm.tif, 2025009FA_MI_Jul_YSMP_SfM_Ortho_5cm.tif) were assessed using the AeroPoints and GPS Emlid check shots. It should also be noted that accuracy estimates of the products were for areas of bare ground or low vegetation where GCPs were placed or where the check shot was appropriate for the product. For example, a check shot on the bridge was not used to assess the digital terrain model (DTM) as the bridge was removed as a surface artifact but would be used to assess the digital surface model (DSM), which includes it. Additional sources of error, such as moving objects, may cause accuracy estimates to exceed estimates in localized portions of the products. Lidar data does not penetrate water. The DTM was also compared to previous data surveys at Marsh Island. The spectral accuracy of the multispectral 5-band ortho product (2025009FA_MI_Jul_aPT_5BandOrtho_5cm.tif) was determined by comparing the reflective value of two reflectance calibration tarps that are visible in the imagery to their established value. The two radiometrically calibrated reflective tarps visible in the ortho image have known values of 0.48 (light) and 0.12 (dark). The average value of each tarp was evaluated by extracting all the values for each band within the area of each tarp in the 5-band products. The average values of the light tarp, from band 1 to 5, were 0.57, 0.55, 0.56, 0.55, 0.55. The average values of the dark tarp, from band 1 to 5, were 0.17, 0.16, 0.16, 0.16, and 0.17. The accuracy of the absolute radiometric (thermal) values in the Skydio orthomosaic (2025009FA_MI_Jul_SX10r_Ortho_5cm.tif) were not assessed and no calibrations were performed. The quoted accuracy of the FLIR Boson sensor is +/- 5 degrees Celsius.
    Lidar: The point cloud (2025009FA_MI_Jul_YSMP_LPC.laz) is georeferenced using a post-processed flight path file generated from the raw GPS and IMU data. The accuracy is assessed using the GPS check shots and AeroPoints. The colorization of the points was based on the closest image and may be off by up to 30 cm. Some misalignment in the collected lidar strips on the distal ends of the collection may occur. Users are advised to evaluate the data for their own needs. The accuracy of the LPC ground classification that produced the DTM was not assessed, users are advised to do their own quality control or reclassification. Misclassification of points may have caused inaccuracies in the DTM.
  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 horizontal accuracy of 0.05 m. The aPT image positions have an average xy accuracy of 1.30 m. The SX10r image positions have an average xy accuracy of 0.19 m.
    GPS: Emlid RS3 GPS points have internal precision horizontal RMS of 1.1 cm. AeroPoint average horizontal global accuracy is 3.9 cm.
    Lidar: The horizontal accuracy of the lidar point cloud, and by association the DSM, was assessed against positions of the AeroPoints on reflective tarps (n=6) in the intensity view of the LPC. The horizontal accuracy is variable and within 30 cm.
    SfM: The RGB, multispectral, and thermal orthomosaic was spatially georeferenced using the visible AeroPoint GCPs and created in separate Metashape projects. The horizontal RMSE of the GCPs (n=9) as reported from the RGB Metashape project was x/y 0.03/0.03 m. The horizontal root mean square error (RMSE) of the GCPs (n=10) as reported from the multispectral Metashape project was x/y 0.10/0.01 m. The horizontal RMSE of the GCPs (n=7) as reported from the thermal Metashape project was x/y 0.01/0.01 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 0.05 m. The aPT image positions have an average z accuracy of 1.81 m. The SX10r image positions have an average z accuracy of 0.26 m.
    GPS: Emlid RS3 GPS points have an internal precision vertical RMS average of 1.6 cm. AeroPoint global vertical accuracy is 3.9 cm.
    Lidar and products: The LPC returns within 5 cm of GPS check points not obscured by vegetation were compared, and the RMSE (n=108) was 0.07 m. The lidar DSM vertical RMSE was 0.06 m and the lidar DTM vertical RMSE (n=150) was 0.08 m. When compared to the March 2025 survey (see larger work citation), 90% of the DTM surface was within 1 to 18 cm.
  4. Where are the gaps in the data? What is missing?
    GPS: Check point 133 was removed due to high RMS values.
    Imagery: The YSMP camera triggered every 2 seconds once it reached 60 meters altitude. Images at take-off and landing were removed. A total of 189 YSMP images are on the IDS and were used in structure from motion (SfM) processing. Only the Skydio thermal images (534) were used to make the thermal orthomosaic; the RGB images are not provided. The aPT sensor triggered every two seconds and takes a total of 7 images each time. The aPT took 7 individual images each time, distinguished by a suffix of _1 to _7. All images with a suffix of _7 were removed from this dataset; these are the thermal (LWIR) images that are redundant with the use of the SX10. Images of the MicaSense Calibration panel at the beginning and end of each flight were kept and given the suffix _calibration. Removing photos from takeoff and landing resulted in a total of 3,744 images. Products: The LPC has been classified into “ground (2)” and “created, never classified (0)” and cleaned in Global Mapper to remove water points and reclassify points near the bridge. GeoTIFF products are cloud-optimized and compressed. The DTM and DSM are not fully interpolated to fill all gaps made by water or tree cover. There are 183 check shots and 10 AeroPoint ground control points. The thermal orthomosaic only covers the area around the creek.
  5. How consistent are the relationships among the observations, including topology?
    There were three UAS flights and ten AeroPoint GCPs placed. The first flight used the Skydio to collect thermal and RGB imagery. The second flight used a M600 Pro with the Altum-PT (aPT) sensor attached. The third flight at the lowest tide used the M600 with the YSMP to collect lidar data and RGB images. All elevation data fall into expected ranges of a low-lying coastal marsh. The thermal data was not calibrated and has unrealistic high values.

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 Marsh Island raw data and products that include a lidar point cloud, elevation models, imagery and image list, true-color orthomosaic, thermal orthomosaic, multispectral mosaic, GPS check shots, 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?

Who wrote the metadata?

Dates:
Last modified: 11-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 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_P19TLXVG/2025009FA_MI_Jul_metadata.faq.html>
Generated by mp version 2.9.51 on Mon May 11 14:01:11 2026