Ground reference geospatial data collected on Fire Island National Seashore, NY, USA, September 16-19, 2024

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?
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  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?
   Evans, Alexandra D., Zeigler, Sara L., Bartlett, Marie K., Raphael, Jordan, and Lentz, Erika, 20250513, Ground reference geospatial data collected on Fire Island National Seashore, NY, USA, September 16-19, 2024: data release DOI:10.5066/P13CHR8V, 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/P13CHR8V
   • https://www.sciencebase.gov/catalog/item/67927873d34e88f5864c49b0

   Other_Citation_Details:

   Evans, A.D., Zeigler, S.L., Bartlett, M.K., Raphael, J., and Lentz, E.E., 2025, Ground reference geospatial data collected on Fire Island National Seashore, NY, USA, September 16-19, 2024: U.S. Geological Survey data release, https://doi.org/10.5066/P13CHR8V.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -73.255226
   East_Bounding_Coordinate: -72.896666
   North_Bounding_Coordinate: 40.722799
   South_Bounding_Coordinate: 40.625106
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/67927873d34e88f5864c49b0?name=2024-022-FA_FIIS_Sept_data_browse.jpg&allowOpen=true (JPEG)

   Example "quadrat" photograph that shows USGS staff collecting data at a sampling location and illustrates the larger landscape context the sample quadrat location was within.

   https://www.sciencebase.gov/catalog/file/get/67927873d34e88f5864c49b0?name=2024-022-FA_FIIS_Sept2024_AOIandPointMap.jpg&allowOpen=true (JPEG)

   A map that shows the locations of areas of interest across Fire Island along with the planned sampling locations.

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

   Beginning_Date: 16-Sep-2024

   Ending_Date: 19-Sep-2024

   Currentness_Reference:

   ground condition at the time of survey

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

   Geospatial_Data_Presentation_Form: tabular digital data, image files (JPEG)
   

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: 18
      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -75.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      

      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 1/298.257223563.
      

      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?

   2024-022-FA_FIIS_September2024_RTKGPS_and_FieldNotes.csv

   The CSV file contains the RTK-GPS survey measurements at the sampling locations and additional RTK-GPS ancillary data for those survey measurements, as well as the field notes and additional measurements collected and noted at each sampling location. The horizontal and vertical CRS for the topographic measurements is NAD83(2011) UTM Zone 18N (Epoch 2010.00) and NAVD88 with geoid 18. The RTK-GPS measurements in the CSV include geographic positions and ellipsoidal heights while the GPS information in each photograph's EXIF is in geographic coordinate system EPSG:4326 (WGS 84). Please note that some headers in the CSV contain characters (e.g. "[" or "%") that may need to be removed prior to importing the table into software such as GIS. (Source: producer defined)

   AOI

   The name of the Area of Interest (AOI) the measurement was taken within. See “2024-022-FA_FIIS_Sept2024_AOIandPointMap.jpg” for AOI names and extents. (Source: producer defined) character string.

   Date

   Sample date YYYY:MM:DD (Source: producer defined) character string

   Easting_18N_m

   Post-processed interpolated Y-coordinate in UTM Zone 18N. (Source: USGS)

   Range of values
   Minimum:	650360.310
   Maximum:	676446.044
   Units:	meters

   Northing_18N_m

   Post-processed interpolated X-coordinate in UTM Zone 18N. (Source: USGS)

   Range of values
   Minimum:	4499085.564
   Maximum:	4510073.238
   Units:	meters

   Elevation_NAVD88_m

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

   Range of values
   Minimum:	0.190
   Maximum:	10.958
   Units:	meters

   Longitude_NAD83[2011]

   Longitude (y) of the measured sample location. Negative values represent West coordinates. (Source: USGS)

   Range of values
   Minimum:	-73.22209637
   Maximum:	-72.91081649
   Units:	decimal degrees

   Latitude_NAD83[2011]

   Latitude (x) of the measured sample location. Positive values represent North coordinates. (Source: USGS)

   Range of values
   Minimum:	40.62891682
   Maximum:	40.72273096
   Units:	decimal degrees

   Ellipsoid_height_NAD83[2011]_m

   Post-processed height in meters in relation to the NAD83(2011) reference ellipsoid GRS 80. (Source: USGS)

   Range of values
   Minimum:	-31.493
   Maximum:	-20.735
   Units:	meters

   Point_Name

   The name of the point sample location as assigned in the field. Each name begins with the name of the AOI in which the point was collected. Names that are numbers combined with “_stkd” indicates that they were pre-determined, pre-numbered points navigated to in the field using the “stake out” feature of the Emlid. Points with names without the phrase "_stkd" were not pre-determined locations but rather points taken on-the-fly in the field (see processing step section). Point names containing the word “Phone” had their location estimated via an integrated cellphone GPS system rather than measured using the Emlid equipment due to poor GPS signal. Refer to the associated photo exif data for approximations of their locations. Points with names including “nps” were of the known NPS benchmark (https://www.ngs.noaa.gov/OPUS/getDatasheet.jsp?PID=BBDX09&style=modern). Points with names including “deck” were of the same spot located on a raised deck near Parks housing to serve as another repeat measurement for evaluating topographic measurement precision. (Source: producer defined) character string

   PhotoRefID

   ID numbers that correspond to the ID numbers provided in the “quadrat” photographs” file names. These ID numbers tie the measurements in the csv to the corresponding photographs on the Imagery Data System. “NA” stands for not applicable. “Not collected” indicates that the expected series of corresponding photographs was mistakenly not taken in the field. (Source: producer defined) character string

   Ecogeomorphic_State

   The ecogeomorphic state present at the point. There are seven possible classes. (Source: producer defined)

   Value	Definition
   developed	Any landcover type that is clearly anthropogenic, including parking lots, paved or unpaved roads, residential properties, and recreational facilities/structures.
   beach	Coordinate is located anywhere between the ocean, including intertidal areas, and the base of the primary dune line. If no dune present, the landward boundary could be an anthropogenic structure or where the base of the primary dune would be (based on neighboring areas) in cases where an overwash is present. Can occur on both the ocean- and bay-side of the island in cases where intertidal marsh is not present.
   primary dune	Area between the primary dune toe and the island interior. In cases where multiple dune lines are present, include the rear swale up to the toe of the secondary dune line. Can occur on both the ocean- and bay-side of the island in cases where intertidal marsh is not present.
   interior sand flat	Area landward of the primary dune line that is flat with minimal vegetation. Typically, caused by overwash.
   upland interior	Area landward of the primary dune line. Can extend all the way to the edge of intertidal wetland or to the primary dune line/shoreline at the bay-side of the island. Will typically contain dense, mid- to late-successional vegetation.
   interior wetland	Occurs in an area landward of the primary dune line in the island’s interior. Typically, a pond or ephemeral pool.
   intertidal wetland	A relatively flat, low-lying, intermittently water-covered area with generally halophytic grasses existing on the bay-side of the island. “NA” indicates “not applicable” to the point.

   Landcover_Class_1

   The majority (>=50%) land cover type within the quadrat at the point location. If the cover in the quadrat was split evenly (50%/50%) between two types, “split” was noted in this field along with the two types of land cover present (e.g. “split herbaceous and shrub”). A visual density guide (Terry and Chilingarian, 1955) in combination with group consensus was used to evaluate this attribute. While the percent coverage they occupied in a quadrat was factored into land cover estimates, bare woody stems and sticks were not considered a land cover class and ignored (e.g. If a dead branch covered 10% of a quadrat and the rest was woody cover, “Land Cover 1” was recorded as “woody”, “Land Cover 2” was recorded as “NA” despite “Land Cover 1” only occupying 90% of the quadrat, and the vegetation density was recorded as 90%). There are eight possible classes. (Source: producer defined)

   Value	Definition
   subaqueous	Ocean, ponds, lakes, marine and estuarine subtidal and intertidal that is underwater. Includes whitewater.
   sand	Unvegetated sand, such as that on a beach or area of overwash.
   wrack	Deposited organic material and other debris, typically located along the shore and sometimes throughout the back marsh area of a barrier island.
   herbaceous vegetation	Herbaceous plant cover, e.g. grasses, with no woody components growing on dry substrate.
   woody vegetation	Multi-stemmed woody plants of any height, including shrubs and trees. Can be growing in wet or dry substrate.
   marsh	Salt and freshwater marshes, intertidal aquatic beds exposed at time of data collection, algal mats. Herbaceous vegetation growing in wet substrate, unlike the "herbaceous vegetation" class. Includes muddy/peaty areas around inland ponds (e.g. behind dunes) and inland mud flats.
   exposed intertidal	Muddy and/or wet sandy areas that are not subaqueous during data collection in the intertidal zone (i.e. wet sand near shore and inlets).
   developed	Any landcover type that is clearly anthropogenic, including buildings, manicured lawns, golf courses, paved/gravel roads, active and abandoned railroad tracks, hardened shore (e.g. riprap, jetties).

   Landcover_Class_2

   The second majority (<50% and >=5%) land cover type within the quadrat. If the secondary cover was less than 5%, “NA” was written in this field as the quadrat was deemed close enough to a pure sample. If “Land Cover 1” was 100% cover, this field was “NA”. If the cover was determined to be split in “Land Cover 1”, “split” was noted in this field. If there was a majority land cover type recorded in “Land Cover 1” and the remainder of the quadrat was split about evenly between two types, the two types were noted in this field (e.g. “herbaceous and woody”). As described for the “Land Cover 1” attribute, sticks and bare branches and stems were not considered a land cover class and ignored. There are eight possible classes. (Source: producer defined)

   Value	Definition
   subaqueous	Ocean, ponds, lakes, marine and estuarine subtidal and intertidal that is underwater. Includes whitewater.
   sand	Unvegetated sand, such as that on a beach or area of overwash.
   wrack	Deposited organic material and other debris, typically located along the shore and sometimes throughout the back marsh area of a barrier island.
   herbaceous vegetation	Herbaceous plant cover, e.g. grasses, with no woody components growing on dry substrate.
   woody vegetation	Multi-stemmed woody plants of any height, including shrubs and trees. Can be growing in wet or dry substrate.
   marsh	Salt and freshwater marshes, intertidal aquatic beds exposed at time of data collection, algal mats. Herbaceous vegetation growing in wet substrate, unlike the "herbaceous vegetation" class. Includes muddy/peaty areas around inland ponds (e.g. behind dunes) and inland mud flats.
   exposed intertidal	Muddy and/or wet sandy areas that are not subaqueous during data collection in the intertidal zone (i.e. wet sand near shore and inlets).
   developed	Any landcover type that is clearly anthropogenic, including buildings, manicured lawns, golf courses, paved/gravel roads, active and abandoned railroad tracks, hardened shore (e.g. riprap, jetties).

   Plant_Functional_Group

   The plant functional group present within the quadrat at the point location. If two functional groups were prominent in the quadrat, they were noted together (e.g. “woody and herbaceous”). There are four possible classes. (Source: producer defined)

   Value	Definition
   bare	No plant cover in most of the quadrat (would likely appear bare from the satellite image).
   anthropogenic	Any cover type, including pavement and manicured lawn, maintained by people.
   herbaceous	Herbaceous plants, typically grasses, with no woody components.
   woody	Multi-stemmed woody plants of any height, including shrubs and trees.

   Vegetation_Height_cm

   The height of the vegetation closest to the survey rod as measured with a measuring stick in centimeters. If no vegetation was present within about a 6-inch (15.24 cm) radius of the rod, this field was noted as “NA”, not applicable, as the vegetation height would not be closely associated with the surveyed location. Other points were labeled “NA” if the measurement was not applicable, such as at the known benchmark. Occasionally, for taller (>2 m) vegetation, we estimated the vegetation height relative to our survey rod height (e.g. “2 ft (60.96 cm) above rod”) and reconciled the note to a number value post-fieldwork. Vegetation height estimates reflect what was on the ground and do not factor in overhead tree canopy. Vegetation height was sometimes not collected due to the presence of poison ivy, noted as “not collected”. When there were layers of vegetation at different heights, e.g. a low-lying branch over the quadrat, notes were recorded alongside the vegetation height measurement to indicate which layer the measurement reflects (e.g. “125 at low-lying branch”). (Source: producer defined) character string

   Vegetation_Density_%

   The density (percent cover) of the vegetation within the quadrat. A visual density guide (Terry and Chilingarian, 1955) in combination with group consensus was used to evaluate this attribute. Each evaluator in the group shared their initial approximation of cover without the input of others. The group then discussed any notable differences in their perspectives and came to a consensus for each measurement. As described for the “Land Cover 1” attribute, sticks and bare branches and stems were not included as vegetation in the vegetation density measurements. Vegetation density estimates reflect what was on the ground and do not factor in overhead tree canopy. Vegetation density measurements were only made when a quadrat was used at the sampling location (i.e. no poison ivy was present). “Not collected” indicates that we were not able to evaluate the vegetation density due to the presence of poison ivy or some other factor. “NA” indicates that the measurement was not applicable to the point. (Source: producer defined) character string

   Substrate

   The substrate type present within the quadrat. This was a visual estimate and meant to be a qualitative descriptor to provide additional ecogeomorphic context for the other data, such as noting mud under marsh land cover. There are five possible classes. “NA” indicates that the evaluation was not applicable to the point. If more than one class was present within the quadrat, both classes were noted (e.g. “sand and gravel”). (Source: producer defined)

   Value	Definition
   mud	Mud or peat. Usually wet like in a marsh setting but includes dry/cracking mud flats in intertidal areas and near ponds.
   sand	Fine grained inorganic material (e.g. sediment or rock) roughly 0.1 to 2 mm in size but includes finer materials that are not silt or clay (less than 0.06 mm in size). Can be wet or dry.
   gravel	Coarser grained inorganic material (e.g. sediment or rock) roughly 2 mm to 64 mm in size. Can be wet or dry.
   soil	A drier mixture of organic matter, minerals, gases, liquids, and organisms that together support the life of plants and soil organisms and is not tidally inundated.
   development	Anything obviously anthropogenic, like pavement. Includes stabilization efforts like rip rap.

   Notes

   An open field reserved for any miscellaneous notes that may be relevant, such as anything unusual about the point that is not captured in the other columns, poison ivy presence, presence of the invasive species Phragmites australis (noted as “Phragmites”), shell cover, etc. “RP” stands for random point. We often had to note when a RP was located further into a thicket of unnavigable dense vegetation and we had to survey the edge of the thicket, or if a RP along the shore was located offshore in water. “None recorded” indicates that no notes were taken about the point. (Source: producer defined) character string

   Tilt_angle

   Angle to nadir of the Emlid RS3. “NA” indicates “not applicable” to the measurement (i.e. point was not surveyed with the Emlid RS3). (Source: USGS)

   Range of values
   Minimum:	0.4
   Maximum:	14.2
   Units:	degree

   E_RMS_m

   Root mean square in the X-coordinate. “NA” indicates “not applicable” to the measurement (i.e. point was not surveyed with the Emlid RS3). (Source: producer defined)

   Range of values
   Minimum:	0.012
   Maximum:	0.024
   Units:	meters

   N_RMS_m

   Root mean square in the Y-coordinate. “NA” indicates “not applicable” to the measurement (i.e. point was not surveyed with the Emlid RS3). (Source: producer defined)

   Range of values
   Minimum:	0.012
   Maximum:	0.021
   Units:	meters

   Z_RMS_m

   Root mean square in the Z-coordinate. “NA” indicates “not applicable” to the measurement (i.e. point was not surveyed with the Emlid RS3). (Source: producer defined)

   Range of values
   Minimum:	0.010
   Maximum:	0.031
   Units:	meters

   Avg_end

   The end time of the sample collection period for the averaged XYZ location. “NA” indicates “not applicable” to the measurement (i.e. point was not surveyed with the Emlid RS3). (Source: producer defined)

   Range of values
   Minimum:	2024-09-16 11:01:41.0
   Maximum:	2024-09-19 19:28:54.0
   Units:	time YYYY-MM-DD HH:MM:SS.S UTC-04:00

   GDOP

   Geometric Dilution of Precision (unitless). Describes the error caused by the relative position of the GPS/GNSS satellites where lower values indicate lower error. “NA” indicates “not applicable” to the measurement (i.e. point was not surveyed with the Emlid RS3). (Source: producer defined)

   Range of values
   Minimum:	1.0
   Maximum:	2.3

   Baseline_m

   Distance from the rover to the base station. “NA” indicates “not applicable” to the measurement (i.e. point was not surveyed with the Emlid RS3). (Source: producer defined)

   Range of values
   Minimum:	7826.682
   Maximum:	22497.326
   Units:	meters

   2024-022-FA_FIIS_September2024_ImageLocations.csv

   The CSV file contains the image file names, dates taken, and locations of all the "landscape" and "quadrat" photographs. The image files are stored on IDS and are organized into two collections, one for the "quadrat" photographs and one for the "landscape" photographs. The horizontal CRS for the image locations as stored in the image files on IDS is the World Geodetic Syatem 1984 (WGS84), as recorded by internal cellphone GPS systems unless otherwise noted. This CSV contains the original WGS84 latitude and longitude as well as the coordinates converted to Northing and Easting coordinates (meters) in UTM Zone 18N NAD83 (2011). (Source: producer defined)

   File_Name

   The name of the image file name as stored in IDS. (Source: producer defined) character string

   Date

   The date on which the photograph was taken YYYY:MM:DD (Source: producer defined) character string

   Latitude_WGS84

   Latitude (x) of the measured sample location. Positive values represent North coordinates. (Source: USGS)

   Range of values
   Minimum:	40.6251056
   Maximum:	40.7227986
   Units:	decimal degrees

   Longitude_WGS84

   Longitude (y) of the measured sample location. Negative values represent West coordinates. (Source: USGS)

   Range of values
   Minimum:	-73.2552261
   Maximum:	-72.8966658
   Units:	decimal degrees

   Northing_18N_m_NAD83[2011]

   X-coordinate in UTM Zone 18N as converted from WGS84. (Source: producer defined)

   Range of values
   Minimum:	647570.0647
   Maximum:	677638.784
   Units:	meters

   Easting_18N_m_NAD83[2011]

   Y-coordinate in UTM Zone 18N as converted from WGS84. (Source: producer defined)

   Range of values
   Minimum:	4498603.883
   Maximum:	4510112.607
   Units:	meters

   Entity_and_Attribute_Overview:

   The “quadrat” image file names are formatted to include the field activity number, the location descriptor “FIIS”, and “Photograph Reference ID” (“PhotoRefID”) numbers that correspond to the PhotoRefID values in the survey data spreadsheet, tying the measurements and notes in the spreadsheet to the relevant photographs. The quadrat photos were also appended with a short descriptive phrase at the end to indicate what perspective of the sampling area was shown: “context” for context photographs, “topdown” for top-down photographs, “vegheight” for vegetation height photographs, “sand” photographs for grain size scale photographs, and “log” for photographs of the field notebook whose timestamps were used to assure that the proper photographs were assigned to the right survey measurements -- which were also time stamped. Some one-off descriptive phases were used for photographs taken under unique circumstances, such as “nearby” to capture land cover nearby the measurement but outside the quadrat or “canopy” that captured the canopy cover above the quadrat sampling area if it was under trees. If multiple photographs of the same descriptive phrase were taken, they were numbered chronologically from first to last taken (e.g. “topdown1”, “topdown2”). The PhotoRefID numbers were assigned per sampled point chronologically, from first collected to last collected. The “landscape” image file names were formatted to contain the field activity number, the location descriptor “FIIS”, the date they were taken, and the word “landscape”. The landscape image filenames were also appended with a unique number assigned to the photographs in the chronological order they were taken, separate from the “PhotoRefID” used in the quadrat image filenames.

   Entity_and_Attribute_Detail_Citation: USGS Field Activity 2024-022-FA
   

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Alexandra D. Evans
   • Sara L. Zeigler
   • Marie K. Bartlett
   • Jordan Raphael
   • Erika Lentz
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   Alexandra D. Evans

   U.S. Geological Survey

   Research Geologist

   384 Woods Hole Rd

   Woods Hole, MA
   

   508-548-8700 x2354 (voice)

   adevans@usgs.gov

Why was the data set created?

How was the data set created?

1. From what previous works were the data drawn?

   NPS_Benchmark (source 1 of 1)

   NOAA National Geodetic Survey, 20150625, Shared Solution: National Oceanic and Atmospheric Administration, online.

   Online Links:

   • https://www.ngs.noaa.gov/OPUS/getDatasheet.jsp?PID=BBDX09&style=modern

   Type_of_Source_Media: Digital
   Source_Contribution:

   This is the benchmark with the reference location we used to calculate the positional accuracies of our topographic survey measurements based on repeat measurements made with the Emlid RS3. Point Names including “nps” in 2024-022-FA_FIIS_September2024_RTKGPS_and_FieldNotes.csv (n=8) are measurements of this benchmark location.

2. How were the data generated, processed, and modified?

   Date: 01-Sep-2024 (process 1 of 5)

   PRE-FIELDWORK PLANNING: Prior to fieldwork, four areas of interest across FIIS were identified: (1) the “Lighthouse” AOI that encompassed an area near the Fire Island Lighthouse on the eastern end of the island, (2) the “Sunken Forest” AOI that encompassed the Sunken Forest, (3) the “Otis” AOI that encompassed an area of the Otis Pike Fire Island High Dune Wilderness (Note: the “Otis” AOI was previously called the “Bonus” AOI during data collection as we were unsure if weather would allow us to conduct fieldwork all four scheduled days and it was lowest priority), and (4) the “Breach” AOI that encompassed the western side of a previously breached area that has opened and closed on the eastern end of FIIS over the past few years – also located within the Otis Pike Fire Island High Dune Wilderness near Goose Point. These AOIs were selected based on the variety of land cover they contained as observed in aerial imagery, their geographic spread across the island, and the travel logistics required to access them on the ground. We generated random points within each AOI in our geographic information system (GIS) to create sampling locations, using the “Create Random Points” tool in ArcGIS Pro and specifying a 10 m minimum distance between points to prevent clustering (ArcGIS Pro version 2.8.2). We generated 50 random points for the “Breach” AOI, 50 random points for the “Sunken Forest” AOI, 30 random points for the “Lighthouse” AOI, and 60 random points split evenly across two subareas (30 per subarea) within the “Otis” AOI. Sometimes additional points were manually added to the random point set in and around the AOIs to note areas with, based on aerial imagery, unique looking cover to try to visit them during our time in the field (e.g. we added 11 points to the Lighthouse point set to bring the total number of points up to 41). See file “2024-022-FA_FIIS_Sept2024_AOIandPointMap.jpg” for a map showing the AOIs and the predetermined point locations. The final point count per AOI was 60 in the “Otis” AOI (30 per subarea), 41 in the “Lighthouse” AOI, 50 in the “Breach” AOI, and 50 in the “Sunken Forest” AOI. Shapefiles containing each area’s points were uploaded into projects on the “Emlid Flow” cellphone app (version 11.2), used on two different phones) to use the app’s map feature to navigate to the predetermined locations in the field. All field staff checked that geolocation tagging was enabled in their cell phone camera applications prior to fieldwork.

   Date: 19-Sep-2024 (process 2 of 5)

   IN-FIELD POINT SAMPLING: We collected data at one AOI per day. The “Breach” AOI was completed on 20240916. The “Sunken Forest” AOI was completed on 20240917. The “Otis” AOI (both subareas) was completed on 20240918. The “Lighthouse” AOI was completed on 20240919. XYZ survey measurements were collected with an Emlid RS3 Global Navigation Satellite System receiver in real-time kinetic mode using corrections from the National Park Service (NPS) Real Time Differential Service (NPS NTRIP base station FIIS_RTCM3). The GPS measurements were collected using a 5 second average per measurement. The Emlid RS3’s tilt compensation feature was enabled. The point sampling protocol was as follows: 1. Navigate to a predetermined point via the Emlid Flow (Survey Plus) app “stake out points” feature. The “stake out points” mode helps orient you in the field to where a point is and tells you how far the pre-determined point location is relative to your current location. 2. Position a 1 m x 1 m quadrat on the ground with the predetermined location in the center. 3. Confirm that the recorded sample point number in the survey app and in the field notebook match at each location. 4. Place the survey rod in the center of the quadrat and take an XYZ measurement. 5. Take field photos with quadrat in place. These include: a. A photo of the phone application screen with point number visible (this is to help keep photos organized in phone gallery and provide a time stamp close to the survey measurement time stamp for later reference and file organization), b. A context photo, which includes quadrat in larger landscape setting (take a few steps away from the quadrat when taking the photograph) c. A photo showing the top-down view of quadrat, illustrating the contents of the quadrat. d. If applicable: a vegetation height photograph, which shows the vegetation closest to the survey rod with a measuring stick for scale. e. If applicable: a sand photograph, which shows the grain size of the sand present in the quadrat relative to a quarter in the photograph for scale. f. Any other photographs that may help capture unique conditions at the point as needed (e.g. a photograph looking at the sky that shows canopy cover over a point). 6. Take notes and additional measurements: a. Ecogeomorphic State: The ecogeomorphic state present in the quadrat. b. Land Cover 1: The majority (>=50%) land cover type within the quadrat. If the cover in the quadrat was split evenly (50%/50%) between two types, “split” was noted in this field along with the two types of land cover present (e.g. “split herbaceous and shrub”). A visual density guide (Terry and Chilingarian, 1955) in combination with group consensus was used to evaluate this attribute. While the percent coverage they occupied in a quadrat was factored into land cover estimates, bare woody stems and sticks were not considered a land cover class and ignored (e.g. If a dead branch covered 10% of a quadrat and the rest was woody cover, “Land Cover 1” was recorded as “woody”, “Land Cover 2” was recorded as “NA” despite “Land Cover 1” only occupying 90% of the quadrat, and the vegetation density was recorded as 90%). c. Land Cover 2: The second majority (<50% and >=5%) land cover type within the quadrat. If the secondary cover was less than 5%, “NA” was written in this field as the quadrat was deemed close enough to a pure sample. If “Land Cover 1” was 100% cover, this field was “NA”. If the cover was determined to be split in “Land Cover 1”, “split” was noted in this field. If there was a majority land cover type recorded in “Land Cover 1” and the remainder of the quadrat was split about evenly between two types, the two types were noted in this field (e.g. “herbaceous and woody”). As described for the “Land Cover 1” attribute, sticks and bare branches and stems were not considered a land cover class and ignored. d. Plant Functional Group: The plant functional group present within the quadrat. If two functional groups were prominent in the quadrat, they were noted together (e.g. “woody and herbaceous”). e. Vegetation Height (cm): The height of the vegetation closest to the survey rod as measured with a measuring stick. If no vegetation was present within about a 6-inch (15.24 cm) radius of the rod, this field was noted as “NA” as the vegetation height would not be closely associated with the surveyed location. Occasionally, for taller (>2 m) vegetation, we estimated the vegetation height relative to our survey rod height (e.g. “2 ft (60.96 cm) above rod”) and reconciled the note to a number value post-fieldwork. Vegetation height estimates reflect what was on the ground and do not factor in overhead tree canopy. Vegetation height was sometimes not collected due to the presence of poison ivy. f. Vegetation Density: The density of the vegetation within the quadrat. A visual density guide (Terry and Chilingarian, 1955) in combination with group consensus was used to evaluate this attribute. Each evaluator in the group shared their initial approximation of cover without the input of others. The group then discussed any notable differences in their perspectives and came to a consensus for each measurement. As described for the “Land Cover 1” attribute, sticks and bare branches and stems were not included as vegetation in the vegetation density measurements. Vegetation density estimates reflect what was on the ground and do not factor in overhead tree canopy. Vegetation density measurements were only made when a quadrat was used at the sampling location (i.e. no poison ivy was present). g. Substrate: The substrate type present within the quadrat. This was a visual estimate and meant to be a qualitative descriptor, falling into broad categories like “sand”, “mud”, etc. h. Any additional miscellaneous notes. E.g. Is there anything unusual about the point that is notable and is not captured in the other columns? Was this point not at the predetermined location due to the planned location being precarious/inaccessible? Is there mixed land cover to note? Is the point under a canopy and, if so, what was on the ground under it? Are there a notable number of sticks or bare stems present? Etc. When no quadrat was used at a sampling location, it was normally due to poison ivy presence and noted in this field. 7. Confirm the point has an accompanying survey measurement in RTK app to signal that the measurement was successfully recorded, and that the point was visited. 8. Pick everything up and navigate to the next “staked” point. We also took opportunistic point samples, in addition to the random points, as we noticed unique and/or important for our purposes land cover and features in the field. We did not successfully collect measurements at every pre-determined point due to site navigability, time restrictions, and/or lacking GPS signal. This was most notable at the “Sunken Forest” and “Breach” AOIs. GPS signal was poor throughout much of the Sunken Forest area due to tree cover. We collected one beach transect spontaneously at the “Sunken Forest” AOI (point names 27 through 39; taken at 10 step intervals from the wrack line on the beach to the dune crest) after we discovered that we could not reliably get sufficient GPS signal within the forest to take many “fixed” GPS measurements. Five point samples were collected in the “Sunken Forest” AOI entirely relying on our phone GPS to geotag the photographs we took of the quadrat to serve as the primary location data as we could not get sufficient GPS signal for the survey equipment to get a “fixed” signal -- the cover was important enough to document that we decided to try this backup approach in the moment. The “Breach” area predetermined points were, in hindsight, generated too far apart to feasibly navigate to all of them in the allotted time, so we opted to visit a subset of the points across basic terrain types (e.g. marsh, dune, beach, upland, etc.). Eleven of the 50 pre-determined point locations in the “Breach” AOI and 1 of the 50 pre-determined point locations in the “Sunken Forest” AOI were successfully visited in the field, requiring us to heavily supplement the pre-determined points with opportunistic samples to bolster the viable dataset. Some pre-determined point locations throughout all the AOIs were inaccessible due to terrain like dense shrub thickets and poison ivy. In such cases we often took a measurement at the edge of the thicket (as close as we could get to the pre-determined location) and noted this deviation in our field notes. Occasionally we were unable to collect vegetation height and/or vegetation density data due to poison ivy being present at the location. We did not want to risk contaminating the quadrat and/or measurement stick and transfer poison ivy oil onto our hands. Cellphone photographs were taken using either a Samsung Galaxy S22 Ultra (camera model SM-S908U) or an Apple iPhone 15 Pro.

   Date: 19-Sep-2024 (process 3 of 5)

   IN-FIELD LANDSCAPE PHOTOGRAPHY: While navigating to, from, and across the AOIs, we opportunistically took cell phone photographs of the landscape and any characteristics or features that would be helpful to document and to quickly increase our coverage of data. These photographs were taken while walking, as a passenger from a vehicle, and from the top of the Fire Island Lighthouse. The photographs from the Lighthouse provide a unique perspective and are landscape photos 863 through 919. Cellphone photographs were taken using either a Samsung Galaxy S22 Ultra (model SM-S908U) or an Apple iPhone 15 Pro.

   Date: 10-Apr-2025 (process 4 of 5)

   POST-FIELDWORK DATA PREPARATION: The measurements and notes in the field notebook were transcribed into a tabular spreadsheet alongside the corresponding survey measurements. Minor changes to the fieldnotes were made upon reviewing the data, such as swapping the dominant landcover class from “herbaceous” to “sand” if the primary landcover class had been recorded as “herbaceous” in the field but the vegetation density of a quadrat containing herbaceous vegetation and sand was recorded at less than 50%. These sorts of errors sometimes occurred in the field as we evaluated land cover labels before assessing vegetation density, but they were rectifiable based on the in-field photographs and vegetation density measurements. We also combined the plant functional group classes “woody shrub” and “tree” into a “woody” class, as, in hindsight, we did not consistently distinguish between the two during our in-field evaluations. Any points that were sampled under canopy cover had their relevant land cover class and plant functional group fields changed to “woody”, as we did not consistently label these points with either (a) what was on the ground under the canopy or (b) “tree” or “woody” as the point was under canopy. We opted to recategorize these points as “woody” as that cover type is what would be seen from an aerial perspective, which was relevant for our project goals, and we have the ground photos as reference if the labels need to be reprocessed for other projects and uses. We finished calculating vegetation height values for taller vegetation that was noted relative to our survey rod height. Notes were added to the “Notes” field upon reviewing the quadrat photographs if they were missed in the field, such as noting the presence of the invasive species Phragmites australis or if the presence of bare woody stems and/or sticks influenced the land cover and vegetation density estimates. The AOI names were added to the "Point_Name" values to make each point name a unique value, with no repeating point names across all of the rows of the CSV. The photograph file names were systematically renamed to indicate whether they were associated with a measured sample (“quadrat” image files) or taken as an opportunistic landscape photograph (“landscape” image files). The quadrat photos were renamed to include the field activity number, the location descriptor “FIIS”, and “Photograph Reference ID” (“PhotoRefID”) numbers that correspond to the PhotoRefID values in the survey data spreadsheet, tying the measurements and notes in the spreadsheet to the relevant photographs. The quadrat photos were also appended with a short descriptive phrase at the end to indicate what perspective of the sampling area was shown: “context” for context photographs, “topdown” for topdown photographs, “vegheight” for vegetation height photographs, “sand” photographs for grain size scale photographs, and “log” for photographs of the field notebook, the timestamps of which were used to assure that the proper photographs were assigned to the right survey measurements -- which were also time stamped. Some one-off descriptive phases were used for photographs taken under unique circumstances, such as “nearby” to capture land cover nearby the measurement but outside the quadrat or “canopy” that captured the canopy cover above the quadrat sampling area if it was under trees. If multiple photographs of the same descriptive phrase were taken, they were numbered chronologically from first to last taken (e.g. “topdown1”, “topdown2”). The PhotoRefID numbers were assigned per sampled point chronologically, from first collected to last collected. The “landscape” image files were renamed to contain the field activity number, the location descriptor “FIIS”, the date they were taken, and the word “landscape”. The landscape image filenames were also appended with a unique number assigned to the photographs in the chronological order they were taken, separate from the “PhotoRefID” used in the quadrat image filenames. Cell phone photographs from the Apple iPhone had to be converted from HEIC files to JPEG files while maintaining the geolocation metadata for display in GIS. This was done using the following website: https://heic.online/ (accessed in December 2024). The locations of the photographs (both landscape and quadrat) as originally recorded via integrated cellphone GPS in WGS84 were downloaded from IDS in tabular form via the IDS tool for downloading image details. This table was imported into ArcGIS Pro (version 3.4.3) and displayed as points using the “XY Table to Point” tool. The “Project” tool was used to project the points from WGS84 to NAD 1983 (2011) UTM Zone 18N using the “WGS_1984_(ITRF08)_To_NAD_1983_2011” geographic transformation option. The resulting UTM coordinates were then added to the “2024-022-FA_FIIS_September2024_ImageLocations.csv” file as two additional columns. There is a small (less than 1 cm) difference between the original WGS84 and converted NAD83(2011) coordinates. This difference is within expected accuracy estimates for the positions recorded via integrated cellphone GPS. The addition of the converted coordinate columns to the image locations CSV file was done during data release review, which is why this processing step has a completion date of April 10, 2025. The rest of this processing step was completed January 24, 2025. Note that the EXIF headers as stored in the image files on IDS only contain the original WGS84 coordinates.

   Date: 24-Jan-2025 (process 5 of 5)

   IMAGE EXIF TAGGING: All image headers of the renamed image files were edited with exiftool (version 13.00) to add standard USGS tags. The image location EXIF data (latitude and longitude) CRS is WGS84 (EPSG:4326), and is a different CRS from the RTK-GPS measurements as the image EXIF locations were recorded via integrated cellphone GPS. Person who carried out this activity:
   

   Alexandra D. Evans

   U.S. Geological Survey

   384 Woods Hole Rd

   Woods Hole, MA
   

   508-548-8700 x2354 (voice)

   adevans@usgs

3. What similar or related data should the user be aware of?
   Terry, Richard D., and Chilingar, George V., 1955, Summary of "Concerning some additional aids in studying sedimentary formations," by M. S. Shvetsov: Journal of Sedimentary Research Volume 25, Number 3, p. 229-234, SEPM Society for Sedimentary Geology, online.

   Online Links:

   • https://doi.org/10.1306/74d70466-2b21-11d7-8648000102c1865d

   Other_Citation_Details:

   This publication contains the density visual reference guide used to evaluate vegetation density in the field.

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

1. How well have the observations been checked?
   GPS: Based on a comparison of repeat measurements (across all collection days) of a known benchmark to its reported location. Individual RTK measurements are only provided if the solution was FIXED. GPS-enabled smartphone locations were not assessed for accuracy. Accuracy of field observations are a mix of qualitative and quantitative values, please see Process Steps for additional details.
2. How accurate are the geographic locations?
   GPS: The Emlid RS3 GPS points have a XY root mean square error (RMSE) of 4.5 cm based on repeat measurements (across all collection days) of a known benchmark (https://www.ngs.noaa.gov/OPUS/getDatasheet.jsp?PID=BBDX09&style=modern; Point Names including “nps” in 2024-022-FA_FIIS_September2024_RTKGPS_and_FieldNotes.csv (n=8)). Horizontal positions were determined with the GNSS rover receiving real-time differential corrections from the National Parks Service Real-Time GNSS (FIIS station; Mount Point FIIS_RTCM3). The overall horizontal accuracy of the ground reference points calculated using the equation 1.96*RMSE was 8.9 cm and refers to the maximum error you can expect with 95% confidence. However, accuracy varied across the collection days. Refer to each point’s reported X and Y RMSE in 2024-022-FA_FIIS_September2024_RTKGPS_and_FieldNotes.csv for point-specific metrics.
   Images: GPS positions for the photos were recorded in the EXIF:GPS image headers by the phone at the time the photos were taken, unless otherwise noted. GPS-enabled smartphones are typically accurate to within a 4.9 m (16 ft) radius under open sky. However, their accuracy worsens near buildings, bridges, and trees. Quadrat photos with PhotoRefID numbers can be associated with the more accurate corresponding surveyed locations, but the expected accuracy of a 4.9 m radius still applies to the mapped photograph locations based on the cellphone GPS. Therefore, it is recommended to use the RTK-GPS surveyed quadrat locations in the CSV file “2024-022-FA_FIIS_September2024_RTKGPS_and_FieldNotes.csv” when considering the quadrat photo locations, with the exception of files “2024-022-FA_FIIS_20240919_PhotoRefID_152_log.jpg” and “2024-022-FA_FIIS_20240919_PhotoRefID_118_vegheight.jpg” as the GPS latitude and longitude in their EXIF data were added from the survey measurements spreadsheet because the cellphone did not record a GPS location for these two image files – likely due to poor signal when they were taken. Please note that outliers beyond the 4.9 m radius accuracy do occur within this dataset depending on canopy cover, surrounding terrain, and signal strength where/when the photograph was taken. For example, it was noted upon reviewing the data that landscape photo 1104 (2024-022-FA_FIIS_20240916_landscape_1140.jpg), taken in the “Lighthouse” AOI, appeared to be in the center of a Phragmites australis stand when its location was mapped. However, we know from the field experience that landscape photo 1104 was taken directly off the boardwalk somewhere north/northeast of its mapped location, at least 20 m away. In another example, some of the landscape photos taken from a vehicle driving down the beach did not have updated geotagged locations but rather were all referenced to a passed location, making them appear clustered. For a specific example, landscape photographs 204-206 were clustered into a single location near landscape photograph 202. These photographs should have been distributed along the shore, between the locations of landscape photographs 202 and 207. These photographs with poorer horizontal accuracy are still useful for illustrating conditions in their approximate area, and their more accurate location can often be estimated by coupling the perspective and context provided by the georeferenced photographs with sufficiently fine spatial resolution imagery (e.g. a tree in a photograph can be linked to an apparent tree in the imagery and therefore provide an estimate of the photographer’s location).
3. How accurate are the heights or depths?
   GPS: The Emlid RS3 GPS points have a Z RMSE of 2.8 cm based on repeat measurements (across all collection days) of a known benchmark (https://www.ngs.noaa.gov/OPUS/getDatasheet.jsp?PID=BBDX09&style=modern; Point Names including “nps” in 2024-022-FA_FIIS_September2024_RTKGPS_and_FieldNotes.csv (n=8)). However, accuracy varied across the collection days. Refer to each point’s reported Z RMS in 2024-022-FA_FIIS_September2024_RTKGPS_and_FieldNotes.csv for point-specific metrics. Images: Not applicable. Vertical position was not recorded in the images.
4. Where are the gaps in the data? What is missing?
   GPS: 164 GPS point measurements are provided in CSV format (2024-022-FA_FIIS_September2024_RTKGPS_and_FieldNotes.csv). 159 points were measured with the RTK-GPS while 5 of the points are cell phone GPS locations. Please note that there is no point name “SunkenForest_14” in the Sunken Forest AOI measurements, as this measurement was accidently recorded in the field and the number was skipped in the field notebook, therefore removed from the final version of the CSV. Imagery: 601 “quadrat” photographs of the sampling point locations in the field, collected by smartphone for a total size of 3.29 GB with image location information geotagged in WGS84 coordinates by integrated smartphone GPS. Please note that point name “Lighthouse_28_stkd” collected 2024:09:19 only has one corresponding “log” photograph, as other photograph types were mistakenly not collected in the field. Point name “SunkenForest_11” collected 2024:09:17 does not have any corresponding “quadrat” photographs, also due to the photographs being mistakenly skipped in the field. 1261 “landscape” photographs taken opportunistically throughout fieldwork, collected by smartphone for a total size of 8.00 GB with image location information geotagged in WGS84 coordinates by integrated smartphone GPS. There are 1862 images in total, including both 1261 “landscape” and 601 “quadrat” photographs. Please refer to the "DateTimeOriginal" EXIF field for the date and time each photograph was taken, as the GPS date and time fields were unsuccessfully recorded for some of the photographs. Products: Field notes are provided along with their corresponding RTK GPS measurements in a CSV file (2024-022-FA_FIIS_September2024_RTKGPS_and_FieldNotes.csv). 164 data points are presented in this CSV file (one per row), five of which were not surveyed with RTK GPS but rather rely on the geotagged image locations from the integrated phone GPS in their corresponding “quadrat” photographs. These five points have “Phone” in their point name, all collected on 2024:09:17. The landscape and quadrat photographs are provided in JPEG format on the Image Data Service, the link to which is on the ScienceBase page. A provided CSV file (2024-022-FA_FIIS_September2024_ImageLocations.csv) contains the names, dates taken, and locations of all image files (1862 in total).
5. How consistent are the relationships among the observations, including topology?
   There were four areas of interest (AOI) across Fire Island National Seashore (FIIS), with one visited per day in the field. Topographic measurements were taken with an Emlid Reach 3, other in-field observations and height measurements were collected throughout each AOI, and landscape photographs and quadrat photographs were taken with either a Samsung Galaxy S22 Ultra (camera model SM-S908U) or an Apple iPhone 15 Pro, to create a ground reference dataset that illustrates and describes site conditions. Each topographic measurement is accompanied by a "Point_Name" and a "PhotoRefID". The "Point_Name" is the name of the point sample location as assigned in the field. The "PhotoRefId" is an ID number that ties the measurements in the csv to the corresponding photographs on the Imagery Data System, separate from the "Point_Name".

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
   

   United States

   1-888-275-8747 (voice)

   sciencebase@usgs.gov
2. What's the catalog number I need to order this data set? Ground reference geospatial data at Fire Island National Seashore includes topographically surveyed point locations (using an Emlid Reach RS3), data and observations for each point, geotagged “quadrat” photographs of the point sampling locations, and geotagged “landscape” photographs that illustrate broader landscape conditions throughout the island.
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:

     The CSV file 2024-022-FA_FIIS_September2024_RTKGPS_and_FieldNotes.csv contains the RTK GPS measurements and sampling information at each sample location, including AOI, date, vegetation information, land cover information, substrate information, etc. The CSV file also contains ancillary RTK GPS measurement data, like GDOP, average start/end time, tilt angle, etc. in format CSV (version Exported from Excel Office 365 16.01) Size: 0.1

     Network links:

     https://www.sciencebase.gov/catalog/file/get/67927873d34e88f5864c49b0 https://www.sciencebase.gov/catalog/item/67927873d34e88f5864c49b0 https://doi.org/10.5066/P13CHR8V

     Data format:	The cellphone “quadrat” and “landscape” photographs. in format JPEG (version 1.0.0) Size: 11290
     Network links:	https://doi.org/10.5066/P13CHR8V https://doi.org/10.5066/P13TU8KT

   • Cost to order the data: none

Who wrote the metadata?

Dates:

Last modified: 13-May-2025

Metadata author:

Alexandra D. Evans

U.S. Geological Survey, Northeast Region

Research Geologist

384 Woods Hole Rd

Woods Hole, MA

USA

508-548-8700 x2354 (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:

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