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)
20110729
Preliminary hard and soft bottom seafloor substrate map (40m grid) derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at Rose Atoll, Territory of American Samoa, USA.
digital data
http://www.soest.hawaii.edu/pibhmc/
http://www.soest.hawaii.edu/pibhmc/pibhmc_amsamoa_rose_geomorph.htm#substrate
Preliminary hard and soft seafloor substrate map derived
from an unsupervised classification of multibeam backscatter and
bathymetry derivatives at Rose Atoll, Territory of American Samoa, USA.
The dataset was created from gridded (40 m cell size) multibeam bathymetry derivatives collected
aboard R/V AHI; 2 scales of bathymetric variance and bathymetric rugosity, and from multibeam backscatter.
Backscatter data were from a 30 kHz Simrad EM300 sonar, gridded at 5 m.
Very limited seafloor photographs for groundtruthing are available for Rose Atoll and therefore
no supervised classification was performed and we are unable to
visually or empirically evaluate the accuracy of the unsupervised
classification seafloor substrate map. However, in locations such
French Frigate Shoals, NWHI and Tutuila, American Samoa, where ground
truth data are available, the unsupervised classification method is a
robust predictor of substrate type in similar depth ranges and seafloor
environments.
Since groundtruthing was not used to validate the unsupervised classification at
Rose Atoll extreme caution should be used when examining these data to locate
habitat of biological significance. The map should be used in conjunction with
bathymetric derivatives such as rugosity, slope, and Bathymetric Position Index (BPI).
The hard and soft seafloor map is being used to improve
sampling techniques for long-term ecosystem monitoring, to guide
future ground-truthing operations and to identify coral-rich and
species specific environments. This is a preliminary product and
the methods used to generate the map are currently being evaluated
for their accuracy.
Gridded multibeam data were collected aboard the NOAA Ship Hi'ialakai, a 218 ft United States
National Oceanographic and Atmospheric Administration research ship.
The process for deriving the 40-m gridded multibeam bathymetry is described
in Rose_40m.asc.txt, available on www.soest.hawaii.edu/pibhmc.
The resulting grid (rose_40m.grd) was clipped using the ESRI ArcToolbox tool 'Extract by Mask'
leaving only the multibeam data collected on the slopes surrounding the atoll and excluding the
discontinuous data around the base of the slopes.
Classification was carried out using this clipped dataset.
Finer resolution data were available for within the lagoon, and these were classified separately (Rose_5m_hardsoft.jpg).
and are also available on www.soest.hawaii.edu/pibhmc. The metadata for the lagoon hard-soft
classification can be seen at Rose_5m_hardsoft.txt. The process for deriving the 5-m gridded multibeam backscatter
is described in rose-em300-bs-5m.grd.txt. Prior to classification the backscatter data were re-gridded
at 40-m using the resample tool in the Arc Toolbox.
The 40-m rugosity and bathymetric variance grids were generated for use in the classification process
and are not served separately. See the process description portion of this document
for additional informaiton about how the variance and unsupervised layers were derived.
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ground condition
As needed
-168.176635
-168.131605
-14.525078
-14.563367
NCEI Geoportal FilterCoRIS_MetadataCRCP ProjectBenthic Habitat Mapping and Characterization - American Samoa and the U.S. Pacific Remote Island Area1084
CoRIS Theme Thesaurus
EARTH SCIENCE > Oceans > Coastal Processes > Coral Reefs > Coral Reef Ecology > Habitats
EARTH SCIENCE > Oceans > Coastal Processes > Coral Reefs > Coral Reef Ecology > Rugosity
EARTH SCIENCE > Biosphere > Zoology > Corals > Reef Monitoring and Assessment > Mapping
EARTH SCIENCE > Biosphere > Zoology > Corals > Reef Monitoring and Assessment > Mapping > geomorphology Mapping
EARTH SCIENCE > Biosphere > Zoology > Corals > Reef Monitoring and Assessment > Mapping > Habitat Mapping
CoRIS Discovery Thesaurus
Geographic Information > Habitats
ISO 19115 Topic Category
imageryBaseMapsEarthCover
010
CoRIS Place Thesaurus
OCEAN BASIN > Pacific Ocean > American Samoa > Rose Atoll (14S168W0001)
COUNTRY/TERRITORY > United States of America > American Samoa > American Samoa > Rose Atoll (14S168W0001)
CoRIS Region
AmSam
None
These data are not to be used for navigation purposes. Please acknowledge the NOAA Pacific Islands Fisheries
Science Center (PIFSC) Coral Reef Ecosystem Division (CRED) and
the Pacific Islands Benthic Habitat Mapping Center (PIBHMC), and
the Joint Institute for Marine and Atmospheric Research (JIMAR)
and School of Ocean and Earth Science and Technology (SOEST),
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
NOAA IRC
NMFS/PIFSC/CRED
1845 WASP Blvd., Building 176
Honolulu
HI
96818
808 725-5360
808 725-5429
nmfs.pic.credinfo@noaa.gov
e-mail preferred
http://www.soest.hawaii.edu/pibhmc/amsamoa_images/Rose_40m_hardsoft_440.jpg
Hard and Soft Seafloor Substrate
JPEG, PDF
PIBHMC, CRED, PIFSC, NOAA, and JIMAR
Not applicable
Unclassified
Not applicable
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 meters
1 m
Range resolution of sonar ~1.25 cm
Raw sounding resolution: Variable
Vertical accuracy of gridded product: 1% of water depth
Processing steps used to generate the backscatter and bathymetry grids used in the
unsupervised classification process are described in their own metadata that can be found
at www.soest.hawaii.edu/pibhmc.
Rugosity grid was derived from the 40m gridded multibeam bathymetry (clipped as described above)
using the Benthic Terrain Modeler (BTM). The BTM may be downloaded from
https://coast.noaa.gov/digitalcoast//tools/btm/index.html. The BTM, written for ArcGIS ArcGIS 8.x
or 9.x, includes a component for deriving rugosity using methods by Jeff Jenness that he wrote for ArcView 3.x.
Bathymetric variance was calculated from the 40 m multibeam bathymetry in a two-step process
using ArcMap Version 9.2. The first step involved calculating the standard deviation
of the bathymetry layer using the Neighborhood Statistic tool from the Spatial Analyst
pull-down menu in ArcMap Version 9.2. Rectangular neighborhood settings were set to a
height and width of 3 grid cells to create a small-scale variance layer. The standard
deviation output was then squared using the ArcMap Raster Calculater tool. A large-scale
variance layer was also generated using a rectangular neighborhood height and width of 5 grid
cells. The fine-scale variance is useful for defining small features that may indicate
the presence of sediment ripples or possible coral-rich areas whereas the large-scale
variance is useful for defining seafloor ridges, pinnacles, and significant changes
in slope. Bathymetric variance proved to be a useful tool in previous efforts to map
seafloor habitats by Dartnell and Gardner (2004). Their publication can be downloaded
from www.soest.hawaii.edu/pibhmc/pibhmc_documentation.htm. The layers were then opened
as ESRI GRIDS in the image processing software package ENVI (Environment for Visualizing
Images) Version 4.3. A multi-band image was then created with the backscatter, small-
and large-scale variance, and rugosity. A mask was also created in ENVI for the dataset.
Image classification was performed on the multi-band image using the K-Means unsupervised
classification method, which calculates initial class means evenly distributed in the
data space and then iteratively clusters the pixels into the nearest class using a
minimum distance technique. More information about K-Means algorithm can be found in the
ENVI documentation available at www.ittvis.com/envi/. The number of classes was set to two
and all other options were set to default. Class color mapping was performed on the
resulting classified images. The substrate types of hard and soft were assigned based
on a visual interpretation of backscatter intensity and corresponding classes.
20110221
Raster
Grid Cell
544
469
1
Universal Transverse Mercator
-2
0.9996
-171
0
500000
10000000
Row and Column
40
40
meters
D_WGS_1984
WGS_1984
6378137.000000
298.257224
mean lower low water
0.01
meters
Attribute Values
none
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
NOAA IRC
NMFS/PIFSC/CRED
1845 WASP Blvd., Building 176
Honolulu
HI
96818
808 725-5360
808 725-5429
nmfs.pic.credinfo@noaa.gov
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 (ASCIItoRaster).
ftp://ftp.soest.hawaii.edu/pibhmc/website/data/amsamoa/benthichabitatlayers/Rose_40m_HardSoft.zip
None
20190526
20110830
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
NOAA IRC
NMFS/PIFSC/CRED
1845 WASP Blvd., Building 176
Honolulu
HI
96818
808 725-5360
808 725-5429
nmfs.pic.credinfo@noaa.gov
e-mail preferred
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
Universal Time
None
None
20110830064639
None
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https://www.coris.noaa.gov/metadata/records/html/rose_40m_hardsoft.html
6350