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)
20081010
Preliminary hard and soft bottom seafloor substrate map
derived from an unsupervised classification of gridded
backscatter and bathymetry derivatives at Pagan Island, Commonwealth
of the Northern Mariana Islands (CNMI).
digital data
http://www.soest.hawaii.edu/pibhmc/
Preliminary hard and soft seafloor substrate map derived
from an unsupervised classification of multibeam backscatter and
bathymety derivatives at Pagan Island, Commonwealth of the
Northern Mariana Islands (CNMI). The dataset was derived using Reson
8101 backscatter data, bathymetric variance and bathymetric rugosity.
The sonar frequency is 240 kHz for the Reson 8101 backscatter data,
which were resampled to a 5 m grid cell size prior to the classification.
Limited seafloor photographs for groundtruthing are available for Guam and
therefore no supervised classification was performed and we are unable to
visually or quantitatively 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.
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.
Multibeam bathymetry and backscatter data were collected aboard
the R/V AHI (Acoustic Habitat Investigator). See the metadata for
that dataset served separately at www.soest.hawaii.edu/pibhmc.
The batymetric rugosity dataset is also served separately at the
same website. The 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
information about how the variance and unsupervised layers were derived.
20070525
20070608
ground condition
As needed
145.667
145.91
18.19
18.01
NCEI Geoportal FilterCoRIS_Metadata
CRCP Project
Benthic Habitat Mapping and Characterization - Commonwealth of the Northern Mariana Islands and Guam
1398
ISO 19115 Topic Category
environment
007
CoRIS Theme Thesaurus
EARTH SCIENCE > Oceans > Coastal Processes > Coral Reefs > Coral Reef Ecology > Habitats
EARTH SCIENCE > Biosphere > Aquatic Habitat > Benthic Habitat
EARTH SCIENCE > Biosphere > Zoology > Corals > Reef Monitoring and Assessment > Mapping > Habitat Mapping
EARTH SCIENCE > Oceans > Bathymetry/Seafloor Topography > Soft Seafloor Substrate
EARTH SCIENCE > Oceans > Bathymetry/Seafloor Topography > Hard Seafloor Substrate
CoRIS Discovery Thesaurus
Geographic Information > Habitats
None
Hard bottom
Soft bottom
Unsupervised Classification
Acoustic Imagery
Multibeam Backscatter
Backscatter
Bathymetry
Multibeam sonar
Substrate
None
Pagan Island
Commonwealth of the Northern Mariana Islands
United States of America
Central Pacific
CoRIS Region
CNMI
CoRIS Place Thesaurus
OCEAN BASIN > Pacific Ocean > Western Pacific Ocean > Pagan Island > Pagan Island (18N145E0001)
COUNTRY/TERRITORY > Northern Mariana Islands > Pagan > Pagan Island (18N145E0001)
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/CNMI_images/pag-unspv-hardsoft-10m_445.jpg
Hard and Soft Seafloor Substrate
JPEG
PIBHMC, CRED, PIFSC, NOAA, and JIMAR
Not applicable
Unclassified
Not applicable
GeoTIFF file created using ENVI 4.4 in a
Microsoft Windows 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 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, bathymetry,
and bathymetric rugosity grids used in the unsupervised
classification process are described in their own metadata that
can be found at www.soest.hawaii.edu/pibhmc. Backscatter
data were resampled to 5 m grid cell size using the Raster Resample
Tool in the ArcMap Version 9.2 Toolbox. Resampling of the backscatter
was performed after charted data in the GeoTIFF format for the individual
sonar systems were mosaicked using the ArcMap Version 9.2 Toolbox
Mosaic to New Raster function. Bathymetric variance was calculated from the
5 m 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 2 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.
Bathymetric rugosity was calculated using the ArcGIS Benthic
Terrain Modeler (D.J. Wright et al., 2005) accessible at
download at http://www.csc.noaa.gov/products/btm.
The layers were then opened as ESRI GRIDS in the
image processing software package ENVI (Environment for
Visualizing Images) Version 4.3. Two multi-band images were then
created with the backscatter, small- and large-scale variance,
and rugosity. A mask was also created in ENVI for each
backscatter dataset. Image classification was performed
separately on the two multi-band images 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 results from supervised
classification of the backscatter data (also performed in ENVI)
using hard and soft bottom classes from classified seafloor
photographs in other study sites including French Frigate Shoals,
Northwestern Hawaiian Islands and Tutuila, American Samoa. Those
datasets can be found at the PIBHMC website. In addition to the
processing steps mentioned above, the high-intensity, track parallel,
nadir signal was removed from the Reson 8101 backscatter after classification
because it causes false classification results. The nadir signal was removed
by creating a 15 m buffer in ArcGIS around the R/V AHI trackline navigation
data sampled every second. The buffer was used to mask the
Reson 8101 backscatter data and results in the trackline parallel
unclassified data gaps. Methods to most accurately interpolate
across the gaps are currently under investigation.
20080929
Raster
Grid Cell
1342
1671
1
Universal Transverse Mercator
55
0.9996
147
0
500000
0
row and column
10
10
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.
GeoTIFF, .tif
TIFF is a format for storage, transfer, display, and
printing of raster images. The TIFF file structure allows
both the tag and the image data to be encoded into the same
file. GeoTIFF refers to a TIFF file that has geographic
data embedded as tags within the TIFF file. The geographic
data can be used to position the image in the correct
location and geometry on the screen of a geographic
information display. Any GIS, CAD, Image Processing,
Desktop Mapping and other types of systems using geographic
images can read any GeoTiff file. More specifically, files
of this type can be added to ArcInfo and ArcView 8.x or
higher and may be viewed in the Table of Contents as a new
raster layer. Image visualization software that does not
use geography as a basis for image placement can view a
GeoTIFF image as if there were no geographic information in
the TIFF file. For example, GeoTIFF files can be viewed
using Windows Picture and Fax viewer. The GeoTIFF format is
public domain, non-proprietary.
none
http://www.soest.hawaii.edu/pibhmc/cms/data-by-location/cnmi-guam/pagan-island/pagan-island-geomorphology/
None
20200329
20091201
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
20091201043612
None
20070525
20070608
https://www.coris.noaa.gov/metadata/records/html/pag_unspv_hardsoft_10m.html
4344