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Digital elevation models (DEMs) of the Elwha River delta, Washington, July 2018

Metadata Updated: July 6, 2024

This portion of the USGS data release presents digital elevation models (DEMs) derived from bathymetric and topographic surveys conducted on the Elwha River delta in July 2018 (USGS Field Activity Number 2018-648-FA). Nearshore bathymetry data were collected using two personal watercraft (PWCs) and a kayak equipped with single-beam echosounders and survey-grade global navigation satellite systems (GNSS) receivers. Topographic data were collected on foot with survey-grade GNSS receivers mounted on backpacks. Positions of the survey platforms were referenced to 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 based on NGS Geoid09 vertical offsets. The final data were projected in Cartesian coordinates using the Washington State Plane North (meters) coordinate system. A total of 1,216,804 individual elevation points were collected within the survey area between July 23 and July 26, 2018. DEM surfaces were produced from all available elevation data using linear interpolation. Two separate DEMs were constructed. A DEM was produced that covered the entire survey area (approximately 511 ha) with 5-m horizontal resolution. A second DEM with 1-m resolution was produced that covered the river mouth and adjacent areas (approximately 131 ha). The DEMs were created by interpolating between measurements as much as 50 meters apart. For this reason, we cannot evaluate the accuracy of each point in the DEM, only the measurements it is based on. The estimated vertical uncertainties of the bathymetric and topographic measurements are 12 and 5 cm, respectively. Digital data files for each DEM are provided in ESRI ARC ASCII (*.asc) format.

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Dates

Metadata Created Date May 31, 2023
Metadata Updated Date July 6, 2024

Metadata Source

Harvested from DOI EDI

Additional Metadata

Resource Type Dataset
Metadata Created Date May 31, 2023
Metadata Updated Date July 6, 2024
Publisher U.S. Geological Survey
Maintainer
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Identifier USGS:617301f2d34ea36449a882f1
Data Last Modified 20230817
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Metadata Catalog ID https://datainventory.doi.gov/data.json
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id e1d7c298-a8f7-494c-84da-f01ed24acaf9
Harvest Source Id 52bfcc16-6e15-478f-809a-b1bc76f1aeda
Harvest Source Title DOI EDI
Metadata Type geospatial
Old Spatial -123.5916031,48.1351368,-123.5212333,48.1594708
Publisher Hierarchy White House > U.S. Department of the Interior > U.S. Geological Survey
Source Datajson Identifier True
Source Hash 7ccba327d06bb41fcca1f1154922b3b57a54229e1ce6b920f2d30bd6181e8d38
Source Schema Version 1.1
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