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) 20070416 digital data http://www.soest.hawaii.edu/pibhmc/pibhmc_nwhi.htm Gridded bathymetry (20m) of the shelf and slope environments of Nihoa Island, Hawaii, USA. The ASCII includes multibeam bathymetry from the Simrad EM120, Simrad EM1002 Simrad EM300, Simrad EM3002d multibeam sonars collected as of October 2006 by the NOAA Coral Reef Ecosystem Division in depths between 20 and 1000 meters. The ASCII was created using data gathered from multibeam soundings 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. Multibeam data were collected aboard the NOAA Ship Hi'ialakai, a 218' United States National Oceanographic and Atmospheric Administration research ship. The NOAA Ship Hiialakai's survey sensors include a 30 kHz Simrad EM300 sonar and a 300 kHz Simrad EM3002d sonar, which provide bathymetry and imagery data, a TSS/Applanix POS/MV Model 320, which measures position, velocity, attitude and heading, and a Seabird SBE 9/11 plus CTD used to measure sound velocity profiles. Multibeam data were collected aboard the NOAA Ship Hi'ialakai, a 218' United States National Oceanographic and Atmospheric Administration research ship. The NOAA Ship Hiialakai's survey sensors include a 30 kHz Simrad EM300 sonar and a 300 kHz Simrad EM3002d sonar, which provide bathymetry and imagery data, a TSS/Applanix POS/MV Model 320, which measures position, velocity, attitude and heading, and a Seabird SBE 9/11 plus CTD used to measure sound velocity profiles. Specific equipment configurations are documented in cruise metadata from the following cruises: KM0206, HI0501, HI0612. These metadata can be accessed at: http://www.soest.hawaii.edu/pibhmc/pibhmc_cruise-catalog.htm 20021022 20061029 ground condition Complete As needed -162.501792 -161.554103 23.275344 22.758046 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 None Nihoa Island Hawaii Northwestern Hawaiian Islands United States of America CoRIS Place Thesaurus COUNTRY/TERRITORY > United States of America > Hawaii > Honolulu > Nihoa (23N161W0001) OCEAN BASIN > Pacific Ocean > Central Pacific Ocean > Northwestern Hawaiian Islands > Nihoa (23N161W0001) 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/Nihoa_20m_500.jpg Multibeam Bathymetry JPEG PIBHMC, CRED, PIFSC, NOAA and JIMAR Not applicable Unclassified Not applicable ArcGIS ASCII file created 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: Variable, see process description Horizontal position accuracy: Variable, see process description Variable, see process description Raw sounding resolution: Variable, see process description 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. 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. The netCDF grid file is 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. 20070105 Raster Grid Cell 2768 4805 1 Universal Transverse Mercator 4 0.9996 -159 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. Arc ASCII Arc ASCII can be converted to Arc Raster using ArcToolbox Conversion Tools. ftp://ftp.soest.hawaii.edu/pibhmc/website/data/nwhi/bathymetry/Nihoa_20m.asc.zip None 20121220 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 20090219023249 None 20021022 20061029 http://www.coris.noaa.gov/metadata/records/html/cred_gridded_bathy_nihoa_nwhi_20m_asc.html 2942