Ground control point locations and topographic GNSS measurements collected during the UAS survey of the debris flow at South Fork Campground, Sequoia National Park, CA

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., and East, Amy E., 20241219, Ground control point locations and topographic GNSS measurements collected during the UAS survey of the debris flow at South Fork Campground, Sequoia National Park, CA: data release DOI:10.5066/P144KDGN, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P144KDGN
   • https://www.sciencebase.gov/catalog/item/6735365ad34e6fbce7b5d592

   This is part of the following larger work.
   Logan, Joshua B., and East, Amy E., 2024, Aerial imagery and structure-from-motion derived data products from a UAS survey of the debris flow at South Fork Campground, Sequoia National Park, CA: data release DOI:10.5066/P144KDGN, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

   Online Links:

   • https://doi.org/10.5066/P144KDGN

   Other_Citation_Details:

   Suggested Citation: Logan, J.B., East A.E., 2024, Aerial imagery and structure-from-motion derived data products from a UAS survey of the debris flow at South Fork Campground, Sequoia National Park, CA: U.S. Geological Survey data release, https://doi.org/10.5066/P144KDGN.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -118.76724
   East_Bounding_Coordinate: -118.75407
   North_Bounding_Coordinate: 36.35335
   South_Bounding_Coordinate: 36.33801
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/6735365ad34e6fbce7b5d592?name=SFKW_static_base.jpg&allowOpen=True (JPEG)

   GNSS base station occupying temporary benchmark SFKW.

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

   Calendar_Date: 30-Apr-2024

   Currentness_Reference:

   ground condition at time data were collected

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

   Geospatial_Data_Presentation_Form: CSV
   

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: Universal Transverse Mercator
      Universal_Transverse_Mercator:

      UTM_Zone_Number: 11
      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -117.0
      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 0.03
      Ordinates (y-coordinates) are specified to the nearest 0.03
      Planar coordinates are specified in meters
      The horizontal datum used is NAD83 (National Spatial Reference System 2011) (EPSG:1116).
      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 GEOID18

      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 the Universal Transverse Mercator coordinate system, zone 11 north, in units of meters (EPSG:6340) (Source: Producer defined)

   Range of values
   Minimum:	4023370.036
   Maximum:	4024291.168
   Units:	meters

   easting_m

   Easting coordinate of data point relative to the North American Datum of 1983, projected in the Universal Transverse Mercator coordinate system, zone 11 north, in units of meters (EPSG:6340) (Source: Producer defined)

   Range of values
   Minimum:	341614.716
   Maximum:	342307.426
   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 GEOID18. (Source: Producer defined)

   Range of values
   Minimum:	1101.500
   Maximum:	1266.358
   Units:	meters

   code

   code used to describe survey features (Source: producer defined)

   Value	Definition
   BASE	base station
   AT	GCP tarp
   CHLK	GCP chalk mark
   TOPO	topographic point from GNSS-backpack survey

   latitude

   Latitude in decimal degrees, relative to the North American Datum of 1983(2011) (EPSG:6319). (Source: Producer defined)

   Range of values
   Minimum:	36.34249065
   Maximum:	36.35067736
   Units:	decimal degrees

   longitude

   Longitude in decimal degrees, relative to the North American Datum of 1983(2011) (EPSG:6319). (Source: Producer defined)

   Range of values
   Minimum:	-118.76510879
   Maximum:	-118.75720567
   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:	1073.177
   Maximum:	1238.100
   Units:	meters

   observation_time_utc

   Date and time of measurement in coordinated UTC time. (Source: Producer defined)

   Range of values
   Minimum:	2024-04-30 15:57:34
   Maximum:	2024-05-01 19:08:37
   Units:	meters

   horiz_precision_m

   Horizontal precision of GNSS rover measurement, calculated by Trimble Business Center software at the 95 percent confidence level, in units of meters (Source: Producer defined)

   Range of values
   Minimum:	0.004
   Maximum:	0.735
   Units:	meters

   vertical_precision_m

   Vertical precision of GNSS rover measurement, calculated by Trimble Business Center software at the 95 percent confidence level, in units of meters (Source: Producer defined)

   Range of values
   Minimum:	0.009
   Maximum:	1.196
   Units:	meters

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
   • Amy E. East
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: 2024 (process 1 of 1)

   GNSS measurements were made using a Trimble R10-2 rover operating in real-time kinematic mode. Base station corrections were broadcast from a separate Trimble R10-2 occupying a temporary benchmark ("SFKW") established for this project. The approximate base station position was initially derived during the survey using a 180-second autonomous occupation on SFKW. Ground control points (GCPs) consisting of a combination of small square tarps with black-and-white cross patterns and temporary "X" marks made with chalk were placed on the bare ground surface throughout the survey area before the UAS flights. For each GCP measurement the GNSS receiver was placed on a fixed-height tripod and set to occupy the GCP position for a minimum occupation time of one minute. For the topographic data acquisition, a GNSS rover was mounted to a backpack and used to collect continuous 1-second data on bare-ground surfaces of the debris flow site that were accessible on foot. The final coordinates for SFKW were derived using a seven-hour static occupation, submitted to the National Geodetic Survey Online User Positioning Service (OPUS-S). The resulting OPUS solution comforms to the quality standards for a USGS Level II single-base survey according to USGS Techniques and Methods 11-D1. After the survey was completed, the RTK data were adjusted using the final SFKW position using the Trimble Business Center software package. The GNSS data were exported to a comma-delimited text file. 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?
   Rydlund, P.H. Jr., and Densmore, B.K., 2012, Geospatial Methods of Practice and Guidelines for Using Survey-Grade Global Navigation Satellite Systems (GNSS) to Establish Vertical Datum in the United States Geological Survey..

   Online Links:

   • https://pubs.usgs.gov/tm/11d1/tm11-D1.pdf

   Other_Citation_Details:

   Techniques and Methods 11-D1, Chapter 1 of Section D, Field Survey Methods Book 11, Collection and Delineation of Spatial Data.

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?
   The estimated horizontal accuracy of these points ranges from 0.026 meters to 0.735 meters. These values are derived by summing the horizonal precision for each point (calculated at the 95 percent confidence level by the post-processing software and reported in the "horiz_precision_" field of the data file), and the horizontal accuracy of the NGS OPUS-derived position of the GNSS base station operating on temporary benchmark “SFKW” at the 95 percent confidence level (0.026 meters) in quadrature. The mean estimated horizontal accuracy for all of the points is 0.046 meters. The mean estimated horizontal accuracy for the GCP measurements only is 0.027 meters. The mean estimated horizontal accuracy for the backpack-GPS topographic measurements only is 0.047 meters.
3. How accurate are the heights or depths?
   The estimated vertical accuracy of these points ranges from 0.069 meters to 1.198 meters. These values are derived by summing the vertical precision for each point (calculated at the 95 percent confidence level by the post-processing software, and reported in the "vertical_precision_m" field of the data file), and the vertical accuracy of the NGS OPUS-derived position of the GNSS base station operating on temporary benchmark “SFKW” at the 95 percent confidence level (0.069 meters, of which the geoid error (GEOID18) accounts for 0.058 meters) in quadrature. The mean estimated vertical accuracy for all of the points is 0.107 meters. The mean estimated vertical accuracy for the GCP measurements only is 0.071 meters. The mean estimated vertical accuracy for the backpack-GPS topographic measurements only is 0.108 meters.
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 GNSS data 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: 0.172
     Network links:	https://www.sciencebase.gov/catalog/file/get/6735365ad34e6fbce7b5d592?name=SEKI_SouthFork_DebrisFlow_2024_RTK_GNSS.csv https://www.sciencebase.gov/catalog/item/6735365ad34e6fbce7b5d592 https://doi.org/10.5066/P144KDGN

   • 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: 19-Dec-2024

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)