Multispectral aerial imagery from unmanned aerial systems (UAS) flights and image locations: Plum Island Estuary and Parker River NWR (PIEPR), February 27th, 2018

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?
   U.S. Geological Survey, 2019, Multispectral aerial imagery from unmanned aerial systems (UAS) flights and image locations: Plum Island Estuary and Parker River NWR (PIEPR), February 27th, 2018: data release DOI:10.5066/P9O9NSRK, U.S. Geological Survey, Coastal/Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

   Online Links:

   • https://doi.org/10.5066/P9O9NSRK
   • https://www.sciencebase.gov/catalog/item/5c75a772e4b0fe48cb4a5543

   This is part of the following larger work.
   Ganju, Neil K., Brosnahan, Sandra M., Sturdivant, Emily J., Pendleton, Elizabeth A., and Ackerman, Seth D., 2019, Aerial imagery from unmanned aerial systems (UAS) flights and ground control points: Plum Island Estuary and Parker River NWR (PIEPR), February 27th, 2018: data release DOI:10.5066/P9O9NSRK, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/P9O9NSRK
   • https://www.sciencebase.gov/catalog/item/5c0fe16de4b0c53ecb2d1bc3

   Other_Citation_Details:

   Ganju, N.K., Brosnahan, S.M., Sturdivant, E.J., Pendleton, E.A., and Ackerman, S.D., 2019, Aerial imagery from unmanned aerial systems (UAS) flights and ground control points-Plum Island Estuary and Parker River NWR (PIEPR), February 27th, 2018: U.S. Geological Survey data release, https://doi.org/10.5066/P9O9NSRK

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -70.814
   East_Bounding_Coordinate: -70.805
   North_Bounding_Coordinate: 42.777
   South_Bounding_Coordinate: 42.771
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/5c75a772e4b0fe48cb4a5543?name=2018015FA_mica_PlumIsland_browse.jpg (JPEG)

   Browse graphic showing the image locations.

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

   Calendar_Date: 27-Feb-2018

   Currentness_Reference:

   ground condition

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: remote-sensing image
   

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?
      This is a Raster data set.
   2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257224.
      

      Vertical_Coordinate_System_Definition:

      Altitude_System_Definition:

      Altitude_Datum_Name: IGS08 (EPOCH:2017.8707)
      Altitude_Resolution: 0.01
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method: Attribute values
      

7. How does the data set describe geographic features?

   UASmica_2018015FA_nav.csv

   CSV file containing navigation information for every MicaSense image from the USGS field activity 2018-015-FA. (Source: U.S. Geological Survey)

   SourceFile

   Source file of Exif header extraction in the format of xx/zzzz where xx is the flight number as a folder name and zzzz is the image name. (Source: U.S. Geological Survey) Text field

   FileName

   Image name in the USGS format. An example filename and the convention is: 2018015FA_f01m01_20180227T161137Z_IMG_0061_4, where 2018015FA is the internal survey ID, f01m01 is the flight number and internal camera ID, 20180227 is the UTC date in format YYYYMMDD, A 'T' is used to separate UTC date from UTC time in format HHMMSS (161137) followed by a Z, and IMG_0061_4 is the original raw photo name appended to the end of the new filename. (Source: U.S. Geological Survey) Text field

   GPSDateStamp

   UTC date of the photo acquisition in the format YYYY:MM:DD where YYYY is the year, MM is the month, and DD is the day of the month. (Source: U.S. Geological Survey) Text field

   GPSTimeStamp

   UTC time of the photo acquisition in the format HH:MM:SS where HH is hour, MM is minute, and SS is seconds. (Source: U.S. Geological Survey) Text field

   GPSLongitude

   Longitude of the camera location at time of photo acquisition with the negative value indicating western hemisphere. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	-70.8142344
   Maximum:	-70.805469
   Units:	decimal degrees

   GPSLatitude

   Latitude of the camera location at time of photo acquisition with the positive value indicating northern hemisphere. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	42.771265
   Maximum:	42.7766778
   Units:	decimal degrees

   GPSAltitude

   Vertical position in terms of ellipsoidal height of the camera at time of photo acquisition. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	5.266
   Maximum:	107.97
   Units:	meters

   Entity_and_Attribute_Overview:

   There are no additional attributes besides the tags described in data quality section associated with the aerial images. The images are 16-bit, RGBA, TIFF images. Each image is a single wavelength so will appear grayscale when viewed independently. These detailed attributes are for a subset of Exif header information extracted from the images and provided as a separate file. No Exif header modifications were applied to the calibration images.

   Entity_and_Attribute_Detail_Citation: USGS Field Activity 2018-015-FA
   

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • U.S. Geological Survey
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   U.S. Geological Survey

   Attn: Sandra Brosnahan

   Physical Scientist

   384 Woods Hole Road

   Woods Hole, Massachusetts
   

   508-548-8700 x2265 (voice)

   508-457-2310 (FAX)

   sbrosnahan@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: 2018 (process 1 of 6)

   Equipment_and_Setup: A MicaSense RedEdge multispectral camera was mounted on a 3DR Solo quadcopter. MicaSense RedEdge acquires photos at 1.2 Megapixels in 12-bit DNG format. The resolution is 1280 X 960 pixels. MicaSense RedEdge lens focal length is 5.5mm, it has global shutters for all bands, blue, green, red, red edge, and near infrared, with an aperture f2.8. File sizes are generally 1.8 MB on disc. The look direction was directly down from the aircraft. For flight, the camera was set to record images at 2-second intervals, activated before takeoff and deactivated after landing. Flights were flown along pre-planned lines and lasted the duration of the UAS battery life (approximately 15 minutes) or until the flight was completed or aborted. At the start of the mission and throughout the day, the camera shutter was manually triggered with the UAS held over a MicaSense Calibrated Reflectance Panel. The camera was not mounted on a gimbal so capture scenes were dependent on the attitude of the quadcopter.
   3DR GPS module and MicaSense downwelling Light Sensor were connected to the camera with 6-pin cables and secured on top of the aircraft with velcro. The camera received power from a connection to the UAS. The 3DR GPS module is a pre-configured u-Blox NEO-7 that uses a 25 x 25 x 4 mm ceramic patch antenna with a 5 Hz update rate. It records telemetry information including latitude, longitude, altitude, dilution of precision, date and time, roll, pitch, and yaw. The downwelling light sensor measures ambient light for each of the 5 spectral bands captured by the camera. For each camera shutter trigger, it recorded spectral data including spectral irradiance, roll, pitch, yaw, gain, and exposure time. Data from the downwelling light sensor, and GPS module are automatically incorporated into the Exif data for each image. Person who carried out this activity:
   

   U.S. Geological Survey, Woods Hole Coastal and Marine Science Center

   Attn: Sandra Brosnahan

   Physical Scientist

   384 Woods Hole Road

   Woods Hole, Massachusetts
   

   U.S.A.

   508-548-8700 x2265 (voice)

   508 457 2310 (FAX)

   Sbrosnahan@usgs.gov

   Date: 2018 (process 2 of 6)

   Five images are collected at each time point. One image for each of the five wavelengths (each lens is a different wavelength Blue- 475nm, Green- 560nm, Red- 668nm, Red Edge- 717nm, Near IR- 840nm). The underscore in the image name is followed by the band number; _1 corresponds to blue, _2 corresponds to green, _3 corresponds to red, _4 corresponds to red edge, and _5 corresponds to near infrared. Before the images can be used to create photogrammetry products they need to be radiometrically calibrated to account for changing light conditions.
   Before flight, calibration photos are taken of a MicaSense calibrated reflectance panel. The photos are calibrated using a photogrammetry software package (Pix4D), and the images taken of a calibrated reflectance panel, standardized reflectance values provided by Micasense, and data from the downwelling light sensor stored in the image headers. The reflectance values for the panel are 0.61 for near infrared, 0.63 for blue, and 0.64 for green, red and rededge. Calibration photos should be chosen to temporally match the UAS photos as closely as possible. Radiometric differences between files may be due to changing light conditions during flight. Person who carried out this activity:
   

   U.S. Geological Survey, Woods Hole Coastal and Marine Science Center

   Attn: Sandra Brosnahan

   Physical Scientist

   384 Woods Hole Road

   Woods Hole, Massachusetts
   

   U.S.A.

   508-548-8700 x2265 (voice)

   508 457 2310 (FAX)

   Sbrosnahan@usgs.gov

   Date: 2019 (process 3 of 6)

   After a flight, the SD card is removed from the camera, and all files related to the flight are downloaded and organized by flight number. ExifTool by Phil Harvey (version 10.99) was used to update the image names, and to update metadata in image headers.
   An example script for renaming and adding Exif tags for flight 1 can be pasted into a command line (an example of this script to rename and tag flight 1 is):
   exiftool-d 2018015FA_f01m01_%Y%m%dT%H%M%SZ_%%f.%%e "-filename<CreateDate" -Artist="WHCMSC AIM Group" -Credit="U.S. Geological Survey" -Contact="WHSC_data_contact@usgs.gov" -sep "; " -keywords="Plum Island; USGS; MA; 2018-015-FA; UAS; nadir; multispectral; https://doi.org/10.5066/P9O9NSRK" -Copyright="Public Domain. Please credit U.S. Geological Survey" -UserComment="F1" -Caption="Low-altitude aerial photography of Plum Island, MA from survey 2018-015-FA (https://cmgds.marine.usgs.gov/fan_info.php?fa=2018-015-FA)." -ImageDescription="Low-altitude aerial photograph of Plum Island, MA from survey 2018-015-FA (https://cmgds.marine.usgs.gov/fan_info.php?fa=2018-015-FA)." -Caption-Abstract="Low-altitude aerial photography of Plum Island, MA from survey 2018-015-FA (https://cmgds.marine.usgs.gov/fan_info.php?fa=2018-015-FA)." -CopyrightNotice="Public Domain. Please credit U.S. Geological Survey" path\to\imagedirectory
   All TIFF images were renamed to ensure unique filenames and compliance with USGS Coastal/Marine Hazards and Resources Program's best practices for image naming convention. An example filename for this dataset is 2018015FA_f01m01_20180227T161137Z_IMG_0061_4, where 2018015FA is the internal survey ID, f01m01 is the flight number and internal camera ID, 20180227 is the UTC date in format YYYYMMDD, A 'T' is used to separate UTC date from UTC time in format HHMMSS (161137) followed by a Z, and IMG_0061_4 is the original raw photo name appended to the end of the new filename.
   The following tags were updated with standardized values in the image headers to enhance the metadata available:
   Artist-WHCMSC AIM Group
   Credit- U.S. Geological Survey
   Contact- WHSC_data_contact@usgs.gov
   keywords- Plum Island, USGS, MA, 2018-015-FA, UAS, nadir, multispectral, https://doi.org/10.5066/P9O9NSRK
   Copyright- Public Domain. Please credit U.S. Geological Survey
   UserComment- F1 (the flight number)
   Caption- Low-altitude aerial photograph of Plum Island, MA from survey 2018-015-FA (https://cmgds.marine.usgs.gov/fan_info.php?fa=2018-015-FA).
   ImageDescription- Low-altitude aerial photograph of Plum Island, MA from survey 2018-015-FA (https://cmgds.marine.usgs.gov/fan_info.php?fa=2018-015-FA).
   Caption-Abstract- Low-altitude aerial photograph of Plum Island, MA from survey 2018-015-FA (https://cmgds.marine.usgs.gov/fan_info.php?fa=2018-015-FA).
   CopyrightNotice- Public Domain. Please credit U.S. Geological Survey
   GPSTimeStamp- (time copied from -DateTimeOriginal)
   GPSDateStamp- (date copied from -DateTimeOriginal)
   The images are stamped with a date/time stamp recieved from the internal GPS. This populates the Exif tag -Date/Time Original. Person who carried out this activity:
   

   Sandra Brosnahan

   U.S. Geological Survey

   Physical Scientist

   U.S. Geological Survey

   Woods Hole, MA
   

   508-548-8700 x2259 (voice)

   508-457-2310 (FAX)

   sbrosnahan@usgs.gov

   Date: 2019 (process 4 of 6)

   The MicaSense rededge camera records GPS time and date from the GPS connected to the camera. This populates the Exif tag -Date/Time Original. In this process step ExifTool was used to copy the -Date/Time Original stamp into the Exif tag -GPSTimeStamp, and GPSDateStamp.
   This step was done as a batch script, with text-
   for f in f*/*.tif; do exiftool "-GPSTimeStamp<CreateDate" "-GPSDateStamp<CreateDate" $f -overwrite_original; done
   Where $f was the previously edited images.
   Calibration images were omitted from this process. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Seth Ackerman

   Marine Geologist

   384 Woods Hole Road

   Woods Hole, MA
   

   508-548-8700 x2315 (voice)

   508-457-2310 (FAX)

   sackerman@usgs.gov

   Date: 2019 (process 5 of 6)

   ExifTools version 11.28 was used to extract a subset of the Exif header information from the multispectral aerial images to provide image location information in a separate file. The command to extract the information is as follows:
   exiftool.exe -csv -filename -GPSDateStamp -GPSTimeStamp -GPSLongitude -GPSLatitude -GPSAltitude -n fX\*.tif > UASmica_nav_fX.csv
   where fX is the folder name which is the same as the flight number in the format fX where X is the flight number.
   This command was run from a DOS command window on a Windows 7 machine.
   Once a separate file was extracted for each flight, the individual files were concatenated together (UASmica_2018015FA_nav.csv) using the cat command in Cygwin. The VI editor was then used to remove all but the first occurrence of the header line.
   Calibration images were omitted from this process. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: VeeAnn A. Cross

   Marine Geologist

   384 Woods Hole Road

   Woods Hole, MA
   

   508-548-8700 x2251 (voice)

   508-457-2310 (FAX)

   vatnipp@usgs.gov

   Date: 06-Aug-2020 (process 6 of 6)

   Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: VeeAnn A. Cross

   Marine Geologist

   384 Woods Hole Road

   Woods Hole, MA
   

   508-548-8700 x2251 (voice)

   508-457-2310 (FAX)

   vatnipp@usgs.gov

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?
   The GPS used on the UAS has theoretical accuracies of 3 meters horizontally and 10 m vertically. The location values are stored in the Exif header of the images.
2. How accurate are the geographic locations?
   Horizontal positions recorded in the Exif header for each image were derived from 3DR Ublox GPS , which receives signals from GPS and GLONASS satellites in WGS84 (G1150) EPSG::7660, but is otherwise uncorrected. Horizontal locations are considered accurate to approximately 3 meters, but may have inaccuracies greater than 10 meters due to UAS flight path and uncertainty associated with the geotagging process.
3. How accurate are the heights or depths?
   Vertical positions were recorded in the Exif header for each image. Vertical positions are ellipsoidal heights derived from 3DR Ublox GPS NEO-7, which receives signals from GPS and GLONASS satellites, but is otherwise uncorrected. Vertical locations are less accurate than horizontal positions with inaccuracies greater than 10 meters.
4. Where are the gaps in the data? What is missing?
   Seven flights were conducted with the multispectral camera, and 13,415 photos were collected, with 51 additional calibration photos included. Five photographs were captured every 2 seconds, one for each different wavelength. Gaps in sequential 2-second photo intervals exist where photos were removed from the collection. Photos may have been deleted, for reasons including poor photo quality, overexposure, or redundancy. Radiometric calibration photos are included for post processing purposes. Flight four had a temporary increase of speed due to a software bug in the flight control software.
5. How consistent are the relationships among the observations, including topology?
   Photographs were renamed to include survey ID, Camera ID, flight ID, date and time (UTC), and original filename. Metadata contained in image file headers were modified for all photos to include standard USGS tags.

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? This data release includes raw data in the form of geotagged multispectral aerial images in TIFF format and the calibration images. The images themselves are distributed through EROS EarthExplorer with instructions on how to access the images (Data_access_readme.docx) available on ScienceBase. In addition to the images, the aerial image locations in a CSV file (UASmica_2018015FA_nav.csv), a browse graphic (2018015FA_mica_PlumIsland_browse.jpg) and the FGDC CSDGM metadata in XML format (2018015FA_mica_PlumIsland.xml) are available from ScienceBase.
3. What legal disclaimers am I supposed to read?
   Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
4. How can I download or order the data?
   • Availability in digital form:

     Data format:	The images are available through EROS EarthExplorer. The metadata, browse graphic, and a separate file of image locations are available from ScienceBase. in format TIFF Size: 24600
     Network links:	https://earthexplorer.usgs.gov/criteria?dataset_name=UAS_RAW&ordered=USGS_WHCMSC_PIEPR_2018_015_20180227_M01&field=COLLECT_NAME https://www.sciencebase.gov/catalog/item/5c75a772e4b0fe48cb4a5543 https://doi.org/10.5066/P9O9NSRK

     Data format:	The CSV is the file containing the image locations available from ScienceBase. The images themselves are available through EROS EarthExplorer. The metadata and browse graphic are also available from ScienceBase. in format CSV Size: 2
     Network links:	https://www.sciencebase.gov/catalog/file/get/5c75a772e4b0fe48cb4a5543 https://www.sciencebase.gov/catalog/item/5c75a772e4b0fe48cb4a5543 https://doi.org/10.5066/P9O9NSRK

   • Cost to order the data: None

5. What hardware or software do I need in order to use the data set?
   These files require software capable of opening 16-bit, RGBA, TIFF images, and if desired, Exif data associated with the images. In order to download the images from EarthExplorer in bulk mode, the user will need to install additional software on their computer.

Who wrote the metadata?

Dates:

Last modified: 19-Mar-2024

Metadata author:

Sandra Brosnahan

U.S. Geological Survey

Physical Scientist

U.S. Geological Survey

Woods Hole, MA

508-548-8700 x2265 (voice)

508-457-2310 (FAX)

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. (updated on 20240319)

Metadata standard:

Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)