Satellite-derived bathymetry for nearshore benthic habitats in Timor-Leste

Bathymetric data derived from multispectral, high-resolution (2 m) satellite imagery from DigitalGlobe’s WorldView-2 satellite to provide near complete coverage of nearshore terrain along the northern coastline of Timor-Leste, including the district of Oecusse to the west of mainland Timor-Leste and Atauro Island. Satellite images acquired by the NOAA Coral Reef Ecosystem Program (CREP) for the region are from Feb 9, 2010 to October 2, 2013. Methods used by CREP to estimate depths from the WorldView imagery were adapted from instructions developed by Kyle Hogrefe for using IKONOS imagery to derive seafloor elevations in optically clear water (Ehses and Rooney 2015).

Bathymetry values shallower than ~20 m were derived by gauging the relative attenuation of coastal, blue, green and yellow spectral radiance as a function of depth. A multiple linear regression analysis of coastal, blue, green and yellow band spectral values against in-situ depth determined the variables of y-intercept, coastal, blue, green and yellow slope values. The variables for each band were then used in a multivariate slope intercept equation to derive depth over the imagery. Variables and combinations of the bands were adjusted to improve the statistical accuracy and spatial coverage of the final derived bathymetry product. Digital image processing to derive depths was conducted with ENVI, and editing and integration was performed using Esri's ArcGIS.

The method assumes uniform water clarity but deviations from that condition made extraction difficult in water depths greater than 20 m. Results show that biotic material, or sediment in the water column skewed results shallower if the material has a high albedo and deeper if the material has a low albedo.

Data and Resources

Additional Info

Field Value
Last Updated May 1, 2020, 08:41
Created December 20, 2019, 17:56
access_constraints ["Access Constraints: None | Use Constraints: Please cite NOAA Coral Reef Ecosystem Program (CREP) when using the data. \nExample\nCoral Reef Ecosystem Program; Pacific Islands Fisheries Science Center (2017). Satellite-derived bathymetry for nearshore benthic habitats in Timor-Leste. NOAA's National Centers for Environmental Information. Dataset. | Distribution Liability: While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty."]
bbox-east-long 127.4
bbox-north-lat -8.1
bbox-south-lat -9.4
bbox-west-long 124
coupled-resource []
dataset-reference-date [{"type": "publication", "value": "2017"}]
frequency-of-update notPlanned
graphic-preview-description An example of the bathymetry data generated for Timor-Leste from WorldView-2 satellite imagery.
graphic-preview-type JPG
guid gov.noaa.nmfs.inport:46150
licence ["NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose."]
metadata-date 2020-03-24T00:00:00
metadata-language eng
progress completed
resource-type dataset
responsible-party [{"name": "", "roles": ["pointOfContact", "custodian"]}]
spatial {"type": "Polygon", "coordinates": [[[124.0, -9.4], [127.4, -9.4], [127.4, -8.1], [124.0, -8.1], [124.0, -9.4]]]}
spatial_harvester true
temporal-extent-begin 2010-02-09
temporal-extent-end 2013-10-02