Andrew W. Stevens
Guy R. Gelfenbaum
Jonathan A. Warrick
Ian M. Miller
Heather M. Weiner
20220311
Topography data from the Elwha River delta, Washington, July 2018
comma-delimited text
data release
DOI:10.5066/P9QMKAEV
Pacific Coastal and Marine Science Center, Santa Cruz, California
U.S. Geological Survey
https://doi.org/10.5066/P9KXA2SI
https://www.sciencebase.gov/catalog/file/get/6171e1bad34ea36449a86d6b
Andrew W. Stevens
Guy R. Gelfenbaum
Jonathan A. Warrick
Ian M. Miller
Heather M. Weiner
2022
Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, July 2018
data release
DOI:10.5066/P9KXA2SI
Pacific Coastal and Marine Science Center, Santa Cruz, CA
U.S. Geological Survey
https://doi.org/10.5066/P9KXA2SI
This part of the data release presents topography data from the Elwha River delta collected in July 2018. Topography data were collected on foot with global navigation satellite system (GNSS) receivers mounted on backpacks.
Data were obtained to assess the coastal geomorphic response following the removal of two dams on the Elwha River. These data are intended for science researchers, students, policy makers, and the general public. These data can be used with geographic information systems or other software to identify topographic and shallow-water bathymetric features.
Additional information about the field activities from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=2018-648-FA
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
20180723
20180726
Ground condition at time data were collected
None planned
-123.5880084
-123.469442
48.1517393
48.1317125
ISO 19115 Topic Category
elevation
Data Categories for Marine Planning
Bathymetry and Elevation
USGS Thesaurus
topography
GPS measurement
Marine Realms Information Bank (MRIB) keywords
Global Positioning System (GPS) observations
None
U.S. Geological Survey
USGS
Coastal and Marine Hazards and Resources Program
CMHRP
Pacific Coastal and Marine Science Center
PCMSC
USGS Metadata Identifier
USGS:6171e1bad34ea36449a86d6b
Geographic Names Information System (GNIS)
Clallam County
Olympic Peninsula
Strait of Juan de Fuca
Elwha River
None
USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data. This information is not intended for navigation purposes.
U.S. Geological Survey, Pacific Coastal and Marine Science Center
PCMSC Science Data Coordinator
mailing and physical
2885 Mission Street
Santa Cruz
CA
95060
831-427-4747
pcmsc_data@usgs.gov
MATLAB Version: 9.8.0.1396136 (R2020a)
No formal attribute accuracy tests were conducted.
No formal logical accuracy tests were conducted.
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.
A series of benchmarks with known coordinates were established adjacent to the study area to provide geodetic control for the bathymetric and topographic surveys. The positions of the benchmarks were derived from a minimum of two static GNSS occupations. The equipment for the static occupations consisted of a dual frequency Trimble R7 GNSS receiver, a fixed-height tripod, and Trimble Geodetic Model 2 antenna. The static observations were recorded internally in the receiver and the raw observations were processed using the National Geodetic Survey (NGS) Online Positioning User Service (OPUS, https://www.ngs.noaa.gov/OPUS/). Estimated uncertainties in the horizontal position of the individual GNSS occupations were provided by OPUS and ranged between 0.006 m and 0.06 m with an average horizontal uncertainty of 0.02 m. The processed positions from each occupation were averaged to obtain the final reported position of the benchmark. All final positions of the GNSS backpacks were determined using differential corrections from the base station receivers. Manufacturer reported accuracy for the differentially corrected horizontal positions for the Trimble R7, R8, and R10 receivers used in the survey is 0.8 cm + 0.5 ppm. Baselines from the GNSS base station were typically less than 5 km, suggesting a horizontal accuracy of backpack positions to be 0.825 cm relative to the base station. The combined horizontal uncertainty from the base station coordinate solutions and rover trajectories is therefore approximately 3 cm. Uncertainty in the horizontal positions associated with variable posture during data collection of the surveyors is unknown.
The vertical uncertainty of topographic measurements is estimated by combining the uncertainty in the base station coordinate and remote GNSS positions collected in kinematic mode. Uncertainties in the elevation of the base station were provided by NGS OPUS and ranged between 0.02 m and 0.04 m, with an average vertical uncertainty of 0.03 m. Manufacturer reported vertical accuracy in the rover positions is 1.5 cm + 1 ppm for differential corrected kinematic data for the Trimble R7, R8 and R10 receivers used in the surveys. Baseline lengths were typically less than 5 km, suggesting the vertical accuracy of backpack positions to be 2 cm relative to the base station coordinates. Combining the uncertainty in the elevation of the base station coordinates and rover positions yields a total uncertainty in the backpack GNSS positions of approximately 5 cm. Uncertainty in the vertical positions associated with variable posture of the surveyors during data collection is unknown.
Topographic data were collected between July 23 and July 26, 2018, on foot with GNSS equipment mounted on backpacks operating primarily in real-time kinematic (RTK) mode. GNSS backpacks were equipped with a dual-frequency GNSS receivers and handheld data collectors. Differential corrections were transmitted at 1-Hz intervals by a VHF radio to the backpack GNSS receivers from a GNSS base station placed on a benchmark with known horizontal and vertical coordinates relative to the North American Datum of 1983 (CORS96 realization) and North American Vertical Datum of 1988. Prior to data collection, vertical distances between the GNSS antenna and the ground were measured using a tape measure for each topographic surveyor. Hand-held data collectors were used to log raw data and display navigational information allowing surveyors to navigate along predefined survey lines spaced at 25- to 50-m intervals along the delta. Profiles were surveyed from the landward edge of the primary dune over the beach foreshore, to wading depth on the same series of transects as the nearshore bathymetry platforms. Additional topography data between transects were collected to better characterize morphologic variability within the study area.
20180726
Raw topography data were reviewed in Trimble Business Center (TBC) to ensure measured antenna offsets were applied properly in the field. Differential post-processing was performed on points collected in autonomous mode where VHF communication with the base station failed. Orthometric elevations relative to the NAVD88 vertical datum were computed assuming a static geoid value of -20.11 m which is based on the NGS Geoid09 offset at the location of the GNSS base stations. The final point data from the PWCs are projected in cartesian coordinates using the Washington State Plane North, meters coordinate system.
20180731
All available topographic data from the survey were compiled into a comma-delimited text file for distribution
20211020
Point
Point
291777
0.0000001
0.0000001
Decimal degrees
North American Datum of 1983
GRS_1980
6378137.0
298.257222101
North American Vertical Datum of 1988
0.01
meters
Explicit elevation coordinate included with horizontal coordinates
Attribute Table
Table containing attribute information associated with the dataset
Producer defined
datetime_utc
The date and time of data collection in Coordinated Universal Time (UTC).
Producer defined
2018-Jul-23 20:00:21.000
2018-Jul-26 18:00:44.000
date and time in yyyy-mmm-dd HH:MM:SS.FFF format
longitude
Longitude coordinate of data point relative to the North American Datum of 1983
Producer defined
-123.5880084
-123.4694421
Decimal degrees
latitude
Latitude coordinate of data point relative to the North American Datum of 1983
Producer defined
48.1317125
48.1517393
Decimal degrees
easting_m
East coordinate of data point relative to the North American Datum of 1983, projected in the Washington State Plane North, meters, coordinate system
Producer defined
295026.82
303842.32
meters
northing_m
North coordinate of data point relative to the North American Datum of 1983,projected in the Washington State Plane South, meters, coordinate system
Producer defined
129276.32
131642.59
meters
ortho_ht_m
Height in meters relative to the NAVD88 vertical datum, computed assuming a static geoid value of -20.11 m which is based on the NGS Geoid09 offset at the location of the GNSS base station
Producer defined
-1.30
5.65
meters
The first line of the csv file is a header line.
U.S. Geological Survey
U.S. Geological Survey - Science Base
U.S. Geological Survey
mailing and physical
Denver Federal Center, Building 810, Mail Stop 302
Denver
CO
80225
USA
1-888-275-8747
sciencebase@usgs.gov
Topography data are available as a comma-delimited text file (ew18_topo.csv), along with associated FGDC-compliant metadata.
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.
comma-delimited text
MATLAB Version: 9.8.0.1396136 (R2020a)
comma-delimited text file
No compression applied
20.91
https://www.sciencebase.gov/catalog/file/get/6171e1bad34ea36449a86d6b?name=ew18_topo.csv
https://www.sciencebase.gov/catalog/item/6171e1bad34ea36449a86d6b
https://doi.org/10.5066/P9KXA2SI
https://doi.org/10.5066/F72N51GC
Data can be downloaded using the Network_Resource_Name links. The first link is a direct link to download the topographic data. The second link points to a landing page with the topographic data and metadata. The third link points to the landing page for the July 2018 data release. The fourth link points to a landing page for all of the Elwha annual surveys.
None
20220311
U.S. Geological Survey, Pacific Coastal and Marine Science Center
PCMSC Science Data Coordinator
mailing and physical
2885 Mission Street
Santa Cruz
CA
95060
831-427-4747
pcmsc_data@usgs.gov
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998