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Refraction-corrected bathymetric point cloud from the UAS survey of the coral reef off Waiakane, Molokai, Hawaii, 24 June 2018

Metadata Updated: July 6, 2024

This portion of the data release presents a bathymetric point cloud from an unoccupied aerial system (UAS) survey of the coral reef off Waiakane, Molokai, Hawaii, on 24 June 2018. The point cloud has been corrected for the effects of refraction using the techniques described in Dietrich (2017a). The point cloud was created from structure-from-motion (SfM) processing of aerial imagery collected using a UAS with a Ricoh GR II digital camera fitted with a circular polarizing filter. During the survey, a pressure sensor was deployed in the survey area to gain an accurate measurement of the water surface elevation (WSE). After a preliminary dense point cloud was derived from SfM processing, the WSE was used to calculate apparent water depths. These apparent depths along with the estimated camera positions and orientations were used as inputs for the multi-view refraction correction python script (py_sfm_depth.py) described in Dietrich (2017b). The refraction-corrected point cloud showed a substantial improvement in accuracy over the uncorrected point cloud. When compared to the 2013 U.S. Army Corps of Engineers Topobathy Lidar for the area in the central portion of the data set the vertical RMSE for the refraction-corrected point cloud was 0.241 meters with a mean residual of -0.010 meters, whereas the vertical RMSE for the uncorrected point cloud was 0.426 meters with a mean residual of -0.334 meters (see the Vertical Positional Accuracy Report in the metadata for a complete description of the accuracy analysis). For this data release, the final refraction-corrected point cloud is presented in the LAZ format (LAS 1.2 specification). The point cloud has 35,083,205 points with an average point spacing of 0.07 meters. Each point in the point cloud contains an explicit horizontal and vertical coordinate and red, green, and blue (RGB) color values. References Cited: Deitrich, J.R., 2017a, Bathymetric Structure-from-Motion: extracting shallow stream bathymetry from multi-view stereo photogrammetry: Earth Surface Processes and Landforms, https://doi.org/10.1002/esp.4060. Deitrich, J.R., 2017b, py_sfm_depth: Github online repository, https://github.com/geojames/py_sfm_depth.

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 June 1, 2023
Metadata Updated Date July 6, 2024

Metadata Source

Harvested from DOI EDI

Additional Metadata

Resource Type Dataset
Metadata Created Date June 1, 2023
Metadata Updated Date July 6, 2024
Publisher U.S. Geological Survey
Maintainer
@Id http://datainventory.doi.gov/id/dataset/a0761a39aaaa152ceb8193db13e6f949
Identifier USGS:61b7b89dd34e9e224abffd87
Data Last Modified 20220321
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 e76f4465-c930-42a8-be48-8aa710f35f1f
Harvest Source Id 52bfcc16-6e15-478f-809a-b1bc76f1aeda
Harvest Source Title DOI EDI
Metadata Type geospatial
Old Spatial -157.15679,21.08451,-157.15388,21.09352
Publisher Hierarchy White House > U.S. Department of the Interior > U.S. Geological Survey
Source Datajson Identifier True
Source Hash a43ba3569131dbf433c3d53b21e93808b8bea8b869b8c7d5c699f71e6381edc3
Source Schema Version 1.1
Spatial {"type": "Polygon", "coordinates": -157.15679, 21.08451, -157.15679, 21.09352, -157.15388, 21.09352, -157.15388, 21.08451, -157.15679, 21.08451}

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