Pacific Islands Benthic Habitat Mapping Center (PIBHMC), Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), 20100607, Mosaic of gridded multibeam bathymetry and bathymetry derived from multispectral IKONOS satellite imagery of Rose Atoll, American Samoa, USA.
This is a Raster data set. It contains the following raster data types:
Planar coordinates are encoded using Row and Column
Abscissae (x-coordinates) are specified to the nearest 5.000000
Ordinates (y-coordinates) are specified to the nearest 5.000000
Planar coordinates are specified in meters
The horizontal datum used is D_WGS_1984.
The ellipsoid used is WGS_1984.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257224.
NOAA PIFSC CRED, the Pacific Islands Benthic Habitat Mapping Center and Davey Jones Locker GIS Laboratory Oregon State University
The data were derived in support of NOAA Coral Reef Conservation Program goals. Goal 1 is to map all U.S. Coral Reef Ecosystems. This data set specifically addresses Objective 1 and 4: to develop high-resolution benthic maps and to characterize priority deep water reefs and associated habitats. This integration of derived bathymetry data provides a GIS layer with expanded spatial coverage that may be used for benthic and essential fish habitat characterization, and for the study of geologic features. By combining the dataset with other bathymetry, backscatter, derivatives, and in situ data, they collectively compose benthic habitat maps designed to be used to understand and predict shallow depth (0m to 150m) benthic habitats for organisms that inhabit coral reef ecosystems.
This mosaiced derived bathymetry product (rose_dball2) was then integrated with the multibeam sonar data, with sonar data prioritized over derived data, to create the final product (rose_5m_dbmb), through the following steps.
Initially, grdmath, a Generic Mapping Tools (GMT) algorithm that combines multiple grids, was used to combine the mosaicked derived bathymetry product (rose_dball2) with the gridded multibeam bathymetry (rose_5m). The AND operator was used to prioritize use of the multibeam grid over the derived bathymetry grid, where the two overlapped. The resulting product was found to have a noticeable artifact in the form of a marked step in depth on the bank top, where the derived bathymetry and multibeam bathymetry grids met. To avoid this problem, the final product was created by integrating the mosaic derived bathymetry product (rose_dball2) with an extracted subset of the multibeam data that only covered the inner lagoon. First, Fledermaus 3D Editor was used to extract xyz values from the multibeam data to create a subset covering the inner lagoon (rose_lagoon.xyz). The GMT nearneighbor algorithm was used to create a netCDF grid from the lagoon multibeam data. Secondly, xyz points were extracted from the derived bathymetry product (rose_dball2) using the Sample tool, available in ESRI ArcToolbox. The GMT nearneighbor algorithm was used to create a nearneighbor grid from these data. The two nearneighbor grids (one from the lagoon multibeam bathymetry and one from the mosaiced derived bathymetry product) were combined using grdmath. The AND operator was used to prioritize use of the multibeam grid over the derived bathymetry grid, where the two overlapped. The resulting grid (ros_5m_dbmb.nn.grd) was then converted to ASCII format using LINUX/UNIX commands in combination with GMT. (rose_5m_dmbm.asc). GMT is an open source collection of tools for manipulating geographic data sets. Additional information about GMT can be found at: www.soest.hawaii.edu/gmt
Data are collected for resource management and research purposes and are tested for internal consistency; however, no effort is made to compare these data to external references or to other published data.
Horizontal positioning system: GPS C/A Horizontal position accuracy: 25 meters
Range resolution of sonar: varies with depth Raw sounding resolution: varies with depth Vertical accuracy of gridded sonar product: ~ 1% of water depth Vertical accuracy of derived bathymetry product: 5 meter range
These data are believed to be logically consistent though no tests were performed
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- These data are not to be used for navigation purposes. Please acknowledge NOAA Pacific Islands Fisheries Science Center, the Joint Institute for Marine and Atmospheric Research (JIMAR) University of Hawaii and Davey Jones Locker GIS Laboratory Oregon State University as the sources of this information.
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These data are not to be used for navigational purposes. NOAA makes no warranty regarding these data, expressed or implied, nor does the fact of distribution constitute such a warranty. NOAA cannot assume liability for any damages caused by any errors or omissions in these data, nor as a result of the failure of these data to function on a particular system.
|Data format:||Arc ASCII can be converted to Arc Raster using ArcToolbox Conversion Tools (ASCIItoRaster). in format Arc ASCII|
808 725-5360 (voice)
808 725-5429 (FAX)