Preliminary hard and soft bottom seafloor substrate map derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at Tutuila Island, American Samoa, South Pacific.

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Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator:
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)
Publication_Date: 20080602
Title:
Preliminary hard and soft bottom seafloor substrate map derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at Tutuila Island, American Samoa, South Pacific.
Geospatial_Data_Presentation_Form: digital data
Online_Linkage: <http://www.soest.hawaii.edu/pibhmc/>
Description:
Abstract:
Preliminary hard and soft seafloor substrate map derived from an unsupervised classification of multibeam backscatter and bathymety derivatives at Tutuila Island, American Samoa, South Pacific. The dataset was derived using a combination of Simrad em3002d and Reson 8101 backscatter, bathymetric variance and bathymetric rugosity. The sonar frequencies are 300 kHz and 240 kHz for the em3002d and the 8101 data respectively and all data were resampled to 5 m grid cell size prior to the classification. Initial supervised classifications of the backscatter data into hard and soft seafloor substrates, using seafloor photographs for groundtruthing and to define regions of interest, were used to define unsupervised class types and to visually evaluate the accuracy of the unsupervised classification seafloor substrate map.
Purpose:
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.
Supplemental_Information:
Multibeam bathymetry and backscatter data were collected aboard the R/V AHI (Acoustic Habitat Investigator) and the NOAA Ship Hiialakai. See the metadata for those datasets 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.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20040225
Ending_Date: 20060226
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -170.928197
East_Bounding_Coordinate: -170.484814
North_Bounding_Coordinate: -14.195351
South_Bounding_Coordinate: -14.384053
Keywords:
Theme:
Theme_Keyword_Thesaurus: CoRIS Theme Thesaurus
Theme_Keyword:
EARTH SCIENCE > Oceans > Coastal Processes > Coral Reefs > Coral Reef Ecology > Habitats
Theme_Keyword: EARTH SCIENCE > Biosphere > Aquatic Habitat > Benthic Habitat
Theme_Keyword:
EARTH SCIENCE > Biosphere > Zoology > Corals > Reef Monitoring and Assessment > Mapping > Habitat Mapping
Theme_Keyword:
EARTH SCIENCE > Oceans > Bathymetry/Seafloor Topography > Soft Seafloor Substrate
Theme_Keyword:
EARTH SCIENCE > Oceans > Bathymetry/Seafloor Topography > Hard Seafloor Substrate
Theme:
Theme_Keyword_Thesaurus: CoRIS Discovery Thesaurus
Theme_Keyword: Geographic Information > Habitats
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: environment
Theme_Keyword: 007
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: Hard bottom
Theme_Keyword: Soft bottom
Theme_Keyword: Unsupervised Classification
Theme_Keyword: Acoustic Imagery
Theme_Keyword: Multibeam Backscatter
Theme_Keyword: Backscatter
Theme_Keyword: Bathymetry
Theme_Keyword: Multibeam sonar
Theme_Keyword: Substrate
Place:
Place_Keyword_Thesaurus: None
Place_Keyword: Tutuila Island
Place_Keyword: American Samoa
Place_Keyword: South Pacific
Place_Keyword: Pacific Ocean
Place:
Place_Keyword_Thesaurus: CoRIS Place Thesaurus
Place_Keyword:
OCEAN BASIN > Pacific Ocean > American Samoa > Tutuila Island (14S170W0016)
Place_Keyword:
COUNTRY/TERRITORY > United States of America > American Samoa > American Samoa > Tutuila Island (14S170W0016)
Place:
Place_Keyword_Thesaurus: CoRIS Region
Place_Keyword: AmSam
Access_Constraints: None
Use_Constraints:
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.
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:
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)
Contact_Address:
Address_Type: mailing and physical address
Address: NOAA IRC
Address: NMFS/PIFSC/CRED
Address: 1845 WASP Blvd., Building 176
City: Honolulu
State_or_Province: HI
Postal_Code: 96818
Contact_Voice_Telephone: 808 725-5360
Contact_Facsimile_Telephone: 808 725-5429
Contact_Electronic_Mail_Address: nmfs.pic.credinfo@noaa.gov
Contact_Instructions: e-mail preferred
Browse_Graphic:
Browse_Graphic_File_Name:
<http://www.soest.hawaii.edu/pibhmc/amsamoa_images/TUT_unspv_hardvsoft_5m_445.jpg>
Browse_Graphic_File_Description: Hard and Soft Seafloor Substrate
Browse_Graphic_File_Type: JPEG
Data_Set_Credit: PIBHMC, CRED, PIFSC, NOAA, and JIMAR
Security_Information:
Security_Classification_System: Not applicable
Security_Classification: Unclassified
Security_Handling_Description: Not applicable
Native_Data_Set_Environment:
GeoTIFF file created using ENVI 4.3 in a Microsoft Windows environment

Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
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.
Logical_Consistency_Report:
These data are believed to be logically consistent though no tests were performed
Completeness_Report: Complete
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Horizontal positioning system: GPS (SPS) Horizontal position accuracy: 25 meters
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
1 m Range resolution of sonar ~1.25 cm Raw sounding resolution: Variable Vertical accuracy of gridded product: 1% of water depth
Lineage:
Process_Step:
Process_Description:
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. Both backscatter datasets (Simrad em3002d and Reson 8101) 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. Mosaics were created in the ESRI GRID format. 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. Two separate sets of variance and rugosity layers were then created with the same pixel dimensions as the the Reson 8101 and Simrad em3002d backscatter datasets. The datasets were handled separately because the difference in sonar frequencies between the two backscatter prevents them from being directly comparable. They should not be merged into one backscatter layer prior to classification. 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. The photographs, classifications, and descriptions of the classification process are available for download at www.soest.hawaii.edu/pibhmc. The two resulting classified images, one for the Reson 8101 dataset and one for the Simrad em3002d dataset, can be mosaicked and exported as GeoTIFF files in either ArcMap or ENVI to create one image containing three classes; soft, hard bottom, and unclassified (background). In addition to the processing steps mentioned above, the high- intensity, track parallel, nadir signal was removed from the Reson 8101 backscatter data prior to classification in ENVI because it is a data acquisition artifact and causes false classification results. The nadir signal was removed by creating a 20 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.
Process_Date: 20080409

Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Grid Cell
Row_Count: 4160
Column_Count: 8181
Vertical_Count: 1

Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name: Universal Transverse Mercator
Universal_Transverse_Mercator:
UTM_Zone_Number: -2
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: 0.9996
Longitude_of_Central_Meridian: -171
Latitude_of_Projection_Origin: 0
False_Easting: 500000
False_Northing: 10000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: Row and Column
Coordinate_Representation:
Abscissa_Resolution: 5
Ordinate_Resolution: 5
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: D_WGS_1984
Ellipsoid_Name: WGS_1984
Semi-major_Axis: 6378137.000000
Denominator_of_Flattening_Ratio: 298.257224
Vertical_Coordinate_System_Definition:
Depth_System_Definition:
Depth_Datum_Name: mean lower low water
Depth_Resolution: 0.01
Depth_Distance_Units: meters
Depth_Encoding_Method: Attribute Values

Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview: none
Entity_and_Attribute_Detail_Citation: none

Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:
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)
Contact_Address:
Address_Type: mailing and physical address
Address: NOAA IRC
Address: NMFS/PIFSC/CRED
Address: 1845 WASP Blvd., Building 176
City: Honolulu
State_or_Province: HI
Postal_Code: 96818
Contact_Voice_Telephone: 808 725-5360
Contact_Facsimile_Telephone: 808 725-5429
Contact_Electronic_Mail_Address: nmfs.pic.credinfo@noaa.gov
Contact_Instructions: e-mail preferred
Resource_Description: Downloadable Data
Distribution_Liability:
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.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: GeoTIFF, .tif
Format_Information_Content:
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.
File_Decompression_Technique: none
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
<http://www.soest.hawaii.edu/pibhmc/pibhmc_amsamoa_tutuila_geomorph.htm>
Fees: None

Metadata_Reference_Information:
Metadata_Date: 20140312
Metadata_Review_Date: 20091201
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:
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)
Contact_Address:
Address_Type: mailing and physical address
Address: NOAA IRC
Address: NMFS/PIFSC/CRED
Address: 1845 WASP Blvd., Building 176
City: Honolulu
State_or_Province: HI
Postal_Code: 96818
Contact_Voice_Telephone: 808 725-5360
Contact_Facsimile_Telephone: 808 725-5429
Contact_Electronic_Mail_Address: nmfs.pic.credinfo@noaa.gov
Contact_Instructions: e-mail preferred
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: Universal Time
Metadata_Access_Constraints: None
Metadata_Use_Constraints: None

CoRIS:
CoRIS_ID: 20091201060548
CoRIS_Children: None
CoRIS_Beginning_Date: 20040225
CoRIS_Ending_Date: 20060226
CoRIS_Metadata_Link:
<http://www.coris.noaa.gov/metadata/records/html/tut_unspv_hardvsoft_5m.html>
CoRIS_Tracking_ID: 4346

Generated by mp version 2.9.13 on Wed Apr 23 10:39:58 2014