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Refraction-corrected bathymetric digital surface model (DSM) 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 digital surface model (DSM) from an unoccupied aerial system (UAS) survey of the coral reef off Waiakane, Molokai, Hawaii, on 24 June 2018. The DSM has a horizontal resolution of 10 centimeters per pixel and has been corrected for the effects of refraction using the techniques described in Dietrich (2017a). The DSM 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 derive an accurate measurement of the mean 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 resulting point cloud was then rasterized to create the DSM. The refraction-corrected DSM showed a substantial improvement in accuracy over a DSM created using 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 DSM was 0.233 meters with a mean residual of -0.013 meters, whereas the vertical RMSE for the uncorrected DSM was 0.428 meters with a mean residual of -0.340 meters (see the Vertical Positional Accuracy Report in the metadata for a complete description of the accuracy analysis). The refraction-corrected bathymetric DSM is presented in a cloud-optimized GeoTIFF format with internal overviews and masks to facilitate cloud-based queries and display. 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/665f70c5f7779c2c0dd8268b095ca99a
Identifier USGS:61b2a50fd34e3bd218621302
Data Last Modified 20231114
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 fdc6bdd4-4a9f-47ec-a292-c143141501e2
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 25c73483d87b2b4b5c705ee4d0b266fe4f0e2d1bc8a50e0b49bc1afb8f213d7f
Source Schema Version 1.1
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