Ground control point locations for UAS surveys of the beaches at Fort Stevens State Park, OR, and Cape Disappointment State Park, WA, July 2021

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?
   Logan, Joshua B., Stevens, Andrew W., and Johnson, Cordell D., 20230623, Ground control point locations for UAS surveys of the beaches at Fort Stevens State Park, OR, and Cape Disappointment State Park, WA, July 2021: data release DOI:10.5066/P9BVTVAW, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P9BVTVAW
   • https://www.sciencebase.gov/catalog/item/62e47162d34e749ac04cb78a

   This is part of the following larger work.
   Logan, Joshua B., Stevens, Andrew W., Harrison, Shawn R., and Johnson, Cordell D., 2023, Aerial imagery and structure-from-motion data products from UAS surveys of the beaches at Fort Stevens State Park, OR, and Cape Disappointment State Park, WA: data release DOI:10.5066/P9BVTVAW, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

   Online Links:

   • https://doi.org/10.5066/P9BVTVAW

   Other_Citation_Details:

   Suggested Citation: Logan, J.B., Stevens, A.W., Harrison, S.R., and Johnson, C.D., 2023, Aerial imagery and structure-from-motion data products from UAS surveys of the beaches at Fort Stevens State Park, OR, and Cape Disappointment State Park, WA: U.S. Geological Survey data release, https://doi.org/10.5066/P9BVTVAW.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -124.07944
   East_Bounding_Coordinate: -123.99640
   North_Bounding_Coordinate: 46.29649
   South_Bounding_Coordinate: 46.20295
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/62e47162d34e749ac04cb78a?name=F01_20210722T140528Z_RB025675.JPG&allowOpen=True (JPEG)

   Aerial image showing example of ground control point used for the UAS surveys.

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

   Calendar_Date: 22-Jul-2021

   Currentness_Reference:

   ground condition at time data were collected

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

   Geospatial_Data_Presentation_Form: comma-delimited text
   

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (68)
   2. What coordinate system is used to represent geographic features?
      

      Grid_Coordinate_System_Name: State Plane Coordinate System 1983
      State_Plane_Coordinate_System:

      SPCS_Zone_Identifier: 4602
      Lambert_Conformal_Conic:

      Standard_Parallel: 47.33333
      Standard_Parallel: 45.83333
      Longitude_of_Central_Meridian: -120.50000
      Latitude_of_Projection_Origin: 45.33333
      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 (EPSG:4269).
      The ellipsoid used is GRS 1980 (EPSG:7019).
      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 (EPSG:5703), derived using GEOID12B

      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?

   Attribute Table

   Table containing attribute information associated with the dataset (Source: Producer defined)

   pid

   Point ID (Source: producer defined) A unique identification code for the point.

   northing_m

   Northing coordinate of data point relative to the North American Datum of 1983, projected in Washington State Plane, South (zone 4602) coordinate system, in units of meters (EPSG:32149) (Source: Producer defined)

   Range of values
   Minimum:	102637.431
   Maximum:	113294.750
   Units:	meters

   easting_m

   Easting coordinate of data point relative to the North American Datum of 1983, projected in Washington State Plane, South (zone 4602) coordinate system, in units of meters (EPSG:32149) (Source: Producer defined)

   Range of values
   Minimum:	224183.415
   Maximum:	230257.265
   Units:	meters

   orthometric_ht_m

   Orthometric height of data point in meters relative to the North American Vertical Datum of 1988 (EPSG:5703), derived using the National Geodetic Survey GEOID12B. (Source: Producer defined)

   Range of values
   Minimum:	0.170
   Maximum:	13.898
   Units:	meters

   latitude_dd

   Latitude in decimal degrees, relative to the North American Datum of 1983 (EPSG:4269). (Source: Producer defined)

   Range of values
   Minimum:	46.20295211
   Maximum:	46.29648622
   Units:	decimal degrees

   longitude_dd

   Longitude in decimal degrees, relative to the North American Datum of 1983 (EPSG:4269). (Source: Producer defined)

   Range of values
   Minimum:	-124.07944220
   Maximum:	-123.99640290
   Units:	decimal degrees

   ellipsoid_ht_m

   Ellipsoid height in meters, referenced to the GRS 1980 ellipsoid (EPSG:7019). (Source: Producer defined)

   Range of values
   Minimum:	-24.114
   Maximum:	-10.231
   Units:	meters

   Entity_and_Attribute_Overview:

   The first row of the csv file is a header line. Each following row represents one ground control point.

   Entity_and_Attribute_Detail_Citation: U.S. Geological Survey
   

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Joshua B. Logan
   • Andrew W. Stevens
   • Cordell D. Johnson
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   U.S. Geological Survey, Pacific Coastal and Marine Science Center

   Attn: PCMSC Science Data Coordinator

   2885 Mission Street

   Santa Cruz, CA
   

   831-427-4747 (voice)

   pcmsc_data@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: Jul-2021 (process 1 of 1)

   Ground control was established using ground control points (GCPs) consisting of a combination of small square tarps with black-and-white cross patterns and temporary "X" marks placed with chalk on the ground surface throughout the survey area. The GCP positions were measured using post-processed kinematic (PPK) GPS, using corrections from GPS base stations located near the survey area. For each GCP measurement the GPS receiver was placed on a fixed-height tripod and set to occupy the GCP for a minimum occupation time of one minute. Post-processing was conducted using the Trimble Business Center software package. Person who carried out this activity:
   

   Joshua Logan

   U.S. Geological Survey, Pacific Coastal and Marine Science Center

   2885 Mission Street

   Santa Cruz, CA
   

   831-460-7519 (voice)

   jlogan@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?
   No formal attribute accuracy tests were conducted.
2. How accurate are the geographic locations?
   GCP positions were measured using survey-grade dual-frequency GPS receivers operating in post-processed-kinematic (PPK) mode. The GPS receivers were placed on short fixed-height tripods and set to occupy each GCP for a minimum occupation time of one minute. The PPK corrections were referenced to a single GPS base station concurrently occupying a nearby benchmark with published horizontal coordinates relative to the North American Datum of 1983. The horizontal positions of the geodetic reference network meet first-order specifications established by the National Geodetic Survey with a horizontal accuracy of 2 cm or better. Manufacturer reported accuracy for the differentially corrected horizontal positions for the GNSS rover is 0.8 cm + 1 ppm. Baselines from the GNSS base station varied between 0.8 km and 5.8 km with a mean of 2.8 km, suggesting the average horizontal accuracy of rover positions to be about 1 cm. Combining the uncertainty in the benchmark and rover yields a total uncertainty of 3 cm. Uncertainty in the horizontal positions associated with tripod centering, antenna height measurement errors, and errors from the weight of the tripod settling onto the GCP tarp during data collection, and possible subsequent rebound of the center of the tarp after removal is unknown.
3. How accurate are the heights or depths?
   GCP positions were measured using survey-grade dual-frequency GPS receivers operating in post-processed-kinematic (PPK) mode. The GPS receivers were placed on short fixed-height tripods and set to occupy each GCP for a minimum occupation time of one minute. The PPK corrections were referenced to a single GPS base station concurrently occupying a nearby benchmark with published vertical coordinates relative to the North American Datum of 1983. The vertical positions of the geodetic reference network meet 2 cm local ellipsoid height specifications established by the National Geodetic Survey. Manufacturer reported accuracy for the differentially corrected vertical positions for the GNSS rover is 1.5 cm + 1 ppm. Baselines from the GNSS base station varied between 0.8 km and 5.8 km with a mean of 2.8 km, suggesting the average vertical accuracy of rover positions to be about 1.8 cm. Combining the uncertainty in the benchmark and rover yields a total uncertainty of 3.8 cm. Uncertainty in the vertical positions associated with tripod centering, antenna height measurement errors, and errors from the weight of the tripod settling onto the GCP tarp during data collection, and possible subsequent rebound of the center of the tarp after removal is unknown.
4. Where are the gaps in the data? What is missing?
   Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
5. How consistent are the relationships among the observations, including topology?
   No formal logical accuracy tests were conducted.

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? The GCP locations are available in a comma-delimited text format.
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 on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
4. How can I download or order the data?
   • Availability in digital form:

     Data format:	The csv file contains coordinates of ground control point locations. in format comma-delimited text Size: 0.005
     Network links:	https://www.sciencebase.gov/catalog/file/get/62e47162d34e749ac04cb78a?name=FortStevens_BensonBeach_2021-07_GCP_positions.csv https://www.sciencebase.gov/catalog/item/62e47162d34e749ac04cb78a https://doi.org/10.5066/P9BVTVAW

   • Cost to order the data: None.

5. What hardware or software do I need in order to use the data set?
   The downloadable data file is available in comma-separated values (CSV) spreadsheet format. Text editing software can be used to open the file, as well as spreadsheet programs, such as Microsoft Excel.

Who wrote the metadata?

Dates:

Last modified: 23-Jun-2023

Metadata author:

U.S. Geological Survey, Pacific Coastal and Marine Science Center

Attn: PCMSC Science Data Coordinator

2885 Mission Street

Santa Cruz, CA

831-427-4747 (voice)

pcmsc_data@usgs.gov

Metadata standard:

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