Andrew W. Stevens
Guy Gelfenbaum
Jonathan A. Warrick
Ian M. Miller
Heather M. Weiner
2017
Topography data from the Elwha River delta, Washington, May 2011
comma-delimited text
data release
DOI:10.5066/F70Z71F5
Santa Cruz, CA
U.S. Geological Survey
https://doi.org/10.5066/F70Z71F5
Andrew W. Stevens
Guy Gelfenbaum
Jonathan A. Warrick
Ian M. Miller
Heather M. Weiner
2017
Bathymetry and topography data from the Elwha River delta, Washington, May 2011
data release
DOI:10.5066/F70Z71F5
Santa Cruz, CA
U.S. Geological Survey
https://doi.org/10.5066/F70Z71F5
This part of the data release presents topography data from the Elwha River delta collected in May 2011. 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 are available online at: http://cmgds.marine.usgs.gov/fan_info.php?fan=W0411PS
20110516
20110517
ground condition at time data were collected
Not planned
-123.581222
-123.538339
48.150987
48.137237
USGS Metadata Identifier
USGS:58587859e4b0e40e53c241f6
USGS Thesaurus
topography
GPS measurement
ISO 19115 Topic Category
elevation
Data Categories for Marine Planning
Bathymetry and Elevation
Marine Realms Information Bank (MRIB) keywords
Global Positioning System (GPS) observations
Global Change Master Directory (GCMD)
GPS (Global Positioning System)
Geographic Names Information System (GNIS)
Clallum 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 navigational purposes.
Andrew W. Stevens
U.S. Geological Survey, Pacific Coastal and Marine Science Center
mailing and physical
2885 Mission St.
Santa Cruz
CA
95060
USA
831-460-7424
astevens@usgs.gov
Repeatability tests were conducted across different survey platforms, but no comparisons to "true" values were conducted.
All data falls within expected ranges.
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.
Topography data were collected between May 16 and May 17, 2011 on foot with GNSS equipment mounted on backpacks operating in real-time kinematic (RTK) mode. A total of 3 GNSS backpacks, each equipped with a dual-frequency GNSS receiver and hand-held data collector, were used during the survey. 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.
20110517
Raw topography data were reviewed in either Trimble Geomatics Office (TGO) or 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. All available topography data were compiled and exported in comma-separated text file for distribution.
20110606
Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed.
20201019
U.S. Geological Survey
VeeAnn A. Cross
Marine Geologist
Mailing and Physical
384 Woods Hole Road
Woods Hole
MA
02543-1598
508-548-8700 x2251
508-457-2310
vatnipp@usgs.gov
Performed minor edits to the metadata to correct typos. No data were changed
20211014
U.S. Geological Survey
Susan A. Cochran
Geologist
Mailing and Physical
2885 Mission Street
Santa Cruz
CA
95060
831-460-7545
scochran@usgs.gov
Point
Lambert Conformal Conic
47.5
48.73333333333333
-120.8333333333333
47.0
500000.0
0.0
coordinate pair
0.001
0.001
METERS
NAD83 (CORS96)
GRS_1980
6378137.0
298.257222101
North American Vertical Datum of 1988
0.001
meters
Explicit elevation coordinate included with horizontal coordinates
Attribute Table
Table containing attribute information associated with the dataset
Producer defined
Survey_Date
The date corresponding to the start of the multi-day survey in mm/dd/yyyy format
Producer Defined
05/16/2011
05/16/2011
date in mm/dd/yyyy format
Longitude
Longitude coordinate of data point relative to the North American Datum of 1983 (CORS96 realization)
Producer defined
-123.581222
-123.538339
Decimal degrees
Latitude
Latitude coordinate of data point relative to the North American Datum of 1983 (CORS96 realization)
Producer defined
48.137237
48.150987
Decimal degrees
X
East coordinate of data point relative to the North American Datum of 1983 (CORS96 realization), projected in the Washington State Plane, North, meters, coordinate system
Producer defined
295538.960
298764.850
meters
Y
North coordinate of data point relative to the North American Datum of 1983 (CORS96 realization), projected in the Washington State Plane, North, meters, coordinate system
Producer defined
130090.610
131546.550
meters
Ellip_Ht_m
Height in meters of data point with reference to the reference ellipsoid
Producer defined
-20.930
-14.450
meters
Ortho_Ht_m
Height in meters of data point with reference to the North American Vertical Datum of 1988 at the base station (-20.11 m above ellipsoid height).
Producer defined
-0.820
5.660
meters
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 (ew11_may_topo.txt), along with associated 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 9.0.0.341360
text
comma-delimited text file
4.9
https://www.sciencebase.gov/catalog/file/get/58587859e4b0e40e53c241f6/?name=ew11_may_topo.txt
Data can be downloaded via the Internet
None
20211014
U.S. Geological Survey, Pacific Coastal and Marine Science Center
PCMSC Science Data Coordinator
mailing and physical
2885 Mission Street
Santa Cruz
CA
95060-5792
US
831-427-4747
pcmsc_data@usgs.gov
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998