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) 20070301 digital data http://www.soest.hawaii.edu/pibhmc/pibhmc_nwhi.htm Gridded bathymetry of the shelf and slope environments of Necker Island, Northwestern Hawaiian Islands, Hawaii, USA. This netCDF includes multibeam bathymetry from the Simrad EM1002 and Simrad EM120 multibeam sonars collected as of October 2006 by the NOAA Coral Reef Ecosystem Division in depths between 20 and 1500 meters. The netCDF grid also includes estimated depths derived from high resolution IKONOS satellite imagery by the NOAA/NOS/NCCOS/CCMA Remote Sensing Team in shallow water between 0 and 16 meters. The netCDF was created using data gathered from multibeam soundings and IKONOS estimated depths for use as a planning and reference document. The data are also being used for benthic habitat mapping, for locating Essential Fish Habitat, and for studying geologic features of the area. Refer to supplemental information for description of instrument and survey. Data were collected aboard the R/V Kilo Moana, a 186' United States Navy owned research vessel. The R/V Kilo Moana's survey sensors include a 12 kHz Simrad EM120 sonar and a 95 kHz Simrad EM1002 sonar, which provide bathymetry and imagery data, a TSS/Applanix POS/MV Model 320, which measures position, velocity, attitude and heading, and a Sippican MK-21/PC based XBT system plus a Seabird SBE 9/11 CTD both of which measured sound velocity profiles. IKONOS estimated depths were produced using rule-based, semi-automated image analysis of high-resolution satellite imagery for nine locations in the Northwestern Hawaiian Islands. For more information about the estimated depth data see the following online link: http://mercury.ornl.gov/metadata/nbii/html/nos/est%5Fdepth%5Fnwhi.html Specific equipment configurations are documented in metadata from IKONOS Estimated Depths and cruises KM0206. These metadata can be accessed at: http://www.soest.hawaii.edu/pibhmc/pibhmc_cruise-catalog.htm 2000 20021115 ground condition Complete As needed -165.083508 -164.070204 23.919511 23.114007 CoRIS Discovery Thesaurus Geographic Information > Bathymetry ISO 19115 Topic Category elevation 006 CoRIS Theme Thesaurus EARTH SCIENCE > Oceans > Bathymetry/Seafloor Topography > Bathymetry None Bathymetry Multibeam sonar estimated depth None Necker Island Hawaii Northwestern Hawaiian Islands United States of America CoRIS Place Thesaurus COUNTRY/TERRITORY > United States of America > Hawaii > Honolulu > Necker Island (23N164W0001) OCEAN BASIN > Pacific Ocean > Central Pacific Ocean > Northwestern Hawaiian Islands > Necker Island (23N164W0001) CoRIS Region NWHI None These data are not to be used for navigation purposes. Please acknowledge NOAA and the Joint Institute for Marine and Atmospheric Research (JIMAR) University of Hawaii as the sources of this information. 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) mailing and physical address

1125B Ala Moana Blvd.

Honolulu HI 96814 (808) 983-3776 (808) 983-2902 pibhmc@soest.hawaii.edu e-mail preferred http://www.soest.hawaii.edu/pibhmc/NWHI_images/Necker_20m_500.jpg Multibeam Bathymetry JPEG PIBHMC, CRED, PIFSC, NOAA and JIMAR Not applicable Unclassified Not applicable netCDF file created using the Generic Mapping Tools (GMT) in a LINUX environment 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. These data are believed to be logically consistent though no tests were performed Complete Horizontal positioning system: GPS (SPS) Horizontal position accuracy: 25 m 1 m Raw sounding resolution: Variable Multibeam swath files are acquired in the Generic Sensor Format (GSF) and are edited on a swath by swath basis using SAIC's SABER editing software. The edited swath files are then combined into a Pure File Magic (PFM) format in SABER and area based editing is performed. The edited PFM is then exported as X,Y,Z points with a defined grid cell size and the points are combined with X,Y,Z IKONOS estimated depth points. The resulting X,Y,Z data are then gridded using xyz2grd, a Generic Mapping Tools (GMT) algorithm that converts an ASCII or binary table to a netCDF grid file format. GMT is an open source collection of tools for manipulating geographic data sets. Grid nodes with more than one value are set to the average value and unconstrained nodes are set to NaN. Finally, the netCDF grid is clipped at a depth that minimizes data gaps for the specified grid cell size and then converted to an ArcGIS ASCII file format using LINUX/UNIX commands in combination with GMT. Additional information about GMT can be found at: www.soest.hawaii.edu/gmt and additional information about the multibeam data processing is recorded in the cruise metadata. 20070228 Raster Grid Cell 4432 5143 1 Universal Transverse Mercator 3 0.9996 -165 0 500000 0 Row and Column 20 20 meters D_WGS_1984 WGS_1984 6378137.000000 298.257224 mean lower low water 0.01 meters Attribute Values Depth values are real values based on the average of the soundings that fell within the extracted grid cells. The number of soundings per grid cell range from >1000 soundings in shallow depths to as few as 20 soundings in deeper areas. A total error budget for this survey has not been developed. Therefore, the accuracy of depth measurements should be considered to be within 1 meter. none 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) mailing and physical address

1125B Ala Moana Blvd.

Honolulu HI 96814 (808) 983-3776 (808) 983-2902 pibhmc@soest.hawaii.edu e-mail preferred Downloadable Data 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. netCDF, .grd This file is formatted as a 2-D binary netCDF grid file. This is the default grid file format used by GMT (Generic Mapping Tools). More information can be found at http://www.soest.hawaii.edu/gmt and http://www.unidata.ucar.edu/software/netcdf. ftp://ftp.soest.hawaii.edu/pibhmc/website/data/nwhi/bathymetry/Necker_20m.grd.zip None 20121217 20090219 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) mailing and physical address

1125B Ala Moana Blvd.

Honolulu HI 96814 (808) 983-3776 (808) 983-2902 pibhmc@soest.hawaii.edu e-mail preferred FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 Universal Time None None 20090219024504 None 20000101 20021115 http://www.coris.noaa.gov/metadata/records/html/cred_gridded_bathy_necker_nwhi_20m_grd.html 2945