Gridded multibeam bathymetry of Apra Harbor, Guam U.S. Territory

Frequently anticipated questions:

• What does this data set describe?
  1. How should this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How should this data set be cited?

   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), 20100901, Gridded multibeam bathymetry of Apra Harbor, Guam U.S. Territory.

   Online Links:

   • <http://www.soest.hawaii.edu/pibhmc>
   • <http://www.soest.hawaii.edu/pibhmc/pibhmc_cnmi_apra_bathy.htm>

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: 144.614

   East_Bounding_Coordinate: 144.676

   North_Bounding_Coordinate: 13.464

   South_Bounding_Coordinate: 13.418

3. What does it look like?

   <http://www.soest.hawaii.edu/pibhmc/CNMI_images/apra_bty_1m_445.jpg> (JPEG)

   Multibeam Bathymetry

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 29-Mar-2008

   Ending_Date: 04-May-2008

   Currentness_Reference: ground condition

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: digital data

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?

      This is a Raster data set. It contains the following raster data types:

      • Dimensions 5061 x 6664 x 1, type Grid Cell

   2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator

      Universal_Transverse_Mercator:

      UTM_Zone_Number: 55

      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.9996

      Longitude_of_Central_Meridian: 147

      Latitude_of_Projection_Origin: 0

      False_Easting: 500000

      False_Northing: 0

      Planar coordinates are encoded using Row and Column
      Abscissae (x-coordinates) are specified to the nearest 1
      Ordinates (y-coordinates) are specified to the nearest 1
      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.
      

7. How does the data set describe geographic features?

   Entity_and_Attribute_Overview:

   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 these data have not been developed. Therefore, the accuracy of depth measurements is reported in the DAPR.

   Entity_and_Attribute_Detail_Citation: none

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • 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)

2. Who also contributed to the data set?

   NOAA OCS, USN FST, PIBHMC, CRED, PIFSC, NOAA, and JIMAR

3. To whom should users address questions about the data?
   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)
   1125B Ala Moana Blvd.
   Honolulu, HI 96814
   

   (808) 983-3776 (voice)
   (808) 983-2902 (FAX)
   pibhmc@soest.hawaii.edu
   

   Contact_Instructions: e-mail preferred

Why was the data set created?

These data were collected in response to a request by the USN for a cooperative modern hydrographic survey with NOAA to provide contemporary hydrographic data to update the nautical charts in the area. The USN plans to use Apra Harbor, Guam as a primary port-of-call. These data will support safe navigation for the USN fleet in Apra Harbor by providing IHO Order 1 hydrography. They will also aid in ongoing habitat mapping efforts by NOAA PIFSC CRED.

These netCDF and ASCII grids were 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.

How was the data set created?

1. From what previous works were the data drawn?

2. How were the data generated, processed, and modified?

   Date: 15-Nov-2010 (process 1 of 1)

   Refer to the the Data Acquisition and Processing Report (DAPR) that can be accessed at: www.soest.hawaii.edu/pibhmc and is included in the ZIP file containing the bathymetry grids for detailed information on the bathymetry data processing steps.

3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

1. How well have the observations been checked?

   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.

2. How accurate are the geographic locations?

   Horizontal positioning system: see DAPR Horizontal position accuracy: see DAPR

3. How accurate are the heights or depths?

   see DAPR Raw sounding resolution: Variable

4. Where are the gaps in the data? What is missing?

   Complete

5. How consistent are the relationships among the observations, including topology?

   These data are believed to be logically consistent though no tests were performed

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None

Use_Constraints:

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, the NOAA Office of Coast Survey, and the USN Fleet Survey Team as the sources of this information.

1. Who distributes the data set? (Distributor 1 of 1)
   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)
   1125B Ala Moana Blvd.
   Honolulu, HI 96814
   

   (808) 983-3776 (voice)
   (808) 983-2902 (FAX)
   pibhmc@soest.hawaii.edu
   

   Contact_Instructions: e-mail preferred

2. What's the catalog number I need to order this data set?

   Downloadable Data

3. What legal disclaimers am I supposed to read?

   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.

4. How can I download or order the data?
   • Availability in digital form:

     Data format:

     These data can be downloaded as either a 2-D binary netCDF raster grid or an ArcGIS ASCII text file. The netCDF grid is the default grid file format used by GMT (Generic Mapping Tools), which created this file. More information can be located at <http://www.soest.hawaii.edu/gmt/and> <http://www.unidata.ucar.edu/software/netcdf/>. The Arc ASCII file, for use in ESRI's (<http://www.esri.com>) GIS software, can be converted to an Arc Raster Grid using ArcToolbox ASCII to Raster conversion tool. in format netCDF

     Network links:

     <ftp://ftp.soest.hawaii.edu/pibhmc/website/data/cnmi-guam/bathymetry/apra_1m_grd.zip>

     Data format:

     These data can be downloaded as either a 2-D binary netCDF raster grid or an ArcGIS ASCII text file. The netCDF grid is the default grid file format used by GMT (Generic Mapping Tools), which created this file. More information can be located at <http://www.soest.hawaii.edu/gmt/and> <http://www.unidata.ucar.edu/software/netcdf/>. The Arc ASCII file, for use in ESRI's (<http://www.esri.com>) GIS software, can be converted to an Arc Raster Grid using ArcToolbox ASCII to Raster conversion tool. in format Arc ASCII

     Network links:

     <ftp://ftp.soest.hawaii.edu/pibhmc/website/data/cnmi-guam/bathymetry/apra_1m_asc.zip>

   • Cost to order the data: None

Who wrote the metadata?

Dates:

Last modified: 20-Dec-2012
Last Reviewed: 02-Dec-2010

Metadata author:

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)
1125B Ala Moana Blvd.
Honolulu, HI 96814

(808) 983-3776 (voice)
(808) 983-2902 (FAX)
pibhmc@soest.hawaii.edu

Contact_Instructions: e-mail preferred

Metadata standard:

FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)