From: hogrefek@geo.oregonstate.edu Date: August 18, 2009 1:13:16 PM PDT To: Joyce Miller Cc: Scott Ferguson , John Rooney , Jonathan Weiss , Frances Lichowski , Tomoko Acoba , Deepsea , Tim Battista , Elliot.Lim@noaa.gov The stats came out similar to other sites with steep slopes (not so great). Considering that the environmental conditions in the images were very good, I think another lesson learned concerning the limits of bathy derivation is that it is less effective on steep slopes. Particularly when there is no flat/gradual slope areas available for establishing the differential attenuation rates between the blue and green bands. Tinian and Saipan had steep slopes, but some areas with more gradual slopes were available to establish the attenuation rate and the products came out with pretty good stats. Identification_Information: Citation: Citation_Information: Originator: Gaia Geo-Analytical in collaboration with Davey Jones Locker GIS Laboratory, Oregon State Universtiy for Coral Reef Ecosystem Division, NOAA Pacific Islands Fisheries Science Center, Pacific Islands Benthic Habitat Mapping Center Publication_Date: 20090818 Title: Mosaic of bathymetry derived from multispectral IKONOS satellite imagery of Alamagan Island, Commonwealth of Northern Mariana Islands, USA Geospatial_Data_Presentation_Form: raster digital data Online_Linkage: http://soest.hawaii.edu/pibhmc Description: Abstract: Bathymetry derived from multispectral IKONOS satellite data. Gridded (5 m cell size) multibeam bathymetry collected aboard NOAA Ship Hiialaka'i and R/V AHI. Bathymetry values shallower than 25 m were derived by gauging the reletive attenuation of blue and green spectral radiance as a function of depth. A multiple linear regression analysis of linearized blue and green band spectral values against depth determined the variables of y-intercept, blue slope and green slope values. Variables then used in multivariate slope intercept formula to derive depth. Variables were adjusted to improve the statistical accuracy and spatial coverage of the final derived bathymetry product. Digital image processing to derive depths conducted with the ENVI 4.5 software program while data editing and integration was performed using ArcGIS 9.3. This dataset is for the shelf environment of Alamagan Island, Commonwealth of Northern Mariana Islands, USA. Purpose: The data were derived in support of NOAA Coral Reef Conservation Program goals. Goal 1 is to map all U.S. Coral Reef Ecosystems. This data set specifically addresses Objective 1 and 4: to develop high-resolution benthic maps and to characterize priority deep water reefs and associated habitats. This integration of derived bathymetry data provides a GIS layer with expanded spatial coverage that may be used for benthic and essential fish habitat characterization, and for the study of geologic features. By combining the dataset with other bathymetry, backscatter, derivatives, and in situ data, they collectively compose benthic habitat maps designed to be used to understand and predict shallow depth (0m to 150m) benthic habitats for organisms that inhabit coral reef ecosystems. Supplemental_Information: Gridded multibeam data were collected aboard the Hi'ialakai, a 218’ United States National Oceanographic and Atmospheric Administration (NOAA) research ship, and aboard the R/V AHI (Acoustic Habitat Investigator), a 25’ survey launch owned and operated by the NOAA Pacific Islands Fisheries Science Center in Honolulu, HI. The metadata for the bathymetry is documented in the product metadata, alamagan_10m.txt http://www.soest.hawaii.edu/pibhmc/pibhmc_cnmi_ala.htm Original IKONOS imagery was purchased to support the Pacific Islands Geographic Information System (GIS) project and National Ocean Service's (NOS) coral mapping activities. Orthographically corrected IKONOS Imagery was provided by NOAA's National Centers for Coastal Ocean Science, Center for Coastal Monitoring and Assessment. The metadata for this IKONOS imagery is documented in the original product metadata, po_107146_metadata.txt and po_135475_metadata.txt. (http://www.soest.hawaii.edu/pibhmc/) Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20030331 Ending_Date: 20070608 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: As needed Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: 145.811875 East_Bounding_Coordinate: 145.854674 North_Bounding_Coordinate: 17.621831 South_Bounding_Coordinate: 17.577768 Keywords: Theme: Theme_Keyword_Thesaurus: CoRIS Theme Keyword Thesaurus 200806 Theme_Keyword: EARTH SCIENCE > Oceans > Bathymetry/Seafloor Topography > Bathymetry Theme: Theme_Keyword_Thesaurus: CoRIS Theme Keyword Thesaurus 200806 Theme_Keyword: EARTH SCIENCE > Oceans > Bathymetry/Seafloor Topography > Water Depth Theme: Theme_Keyword_Thesaurus: CoRIS Theme Keyword Thesaurus 200806 Theme_Keyword: EARTH SCIENCE > Biosphere > Zoology > Corals > Reef Monitoring and Assessment > Remote Sensing > Satellite (digital scans) > IKONOS Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Slope Theme_Keyword: Bathymetry Theme_Keyword: Multibeam sonar Place: Place_Keyword_Thesaurus: None Place_Keyword: Alamagan Island Place_Keyword: Commonwealth of Northern Mariana Islands Place_Keyword: United States of America Place: Place_Keyword_Thesaurus: CoRIS Place Keywords by Ocean - Pacific Ocean April 2007 (without Great Barrier Reef) Place_Keyword: OCEAN BASIN > Pacific Ocean > Western Pacific Ocean > Alamagan Island > Alamagan Island (17N145E0002) Place: Place_Keyword_Thesaurus: CoRIS Place Keywords by Country/Territory - Pacific Ocean November 2007 (without Great Barrier Reef) Place_Keyword: COUNTRY/TERRITORY > Northern Mariana Islands > Alamagan Island > Alamagan Island (17N145E0002) Place_Keyword: COUNTRY/TERRITORY > United States of America > Hawaii > Honolulu (28N165W0001) 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 and Davey Jones Locker GIS Laboratory Oregon State University as the sources of this information. Browse_Graphic: Browse_Graphic_File_Name: Ala_DBall.pdf Browse_Graphic_File_Description: Gridded Bathymetry Browse_Graphic_File_Type: PDF Data_Set_Credit: NOAA PIFSC CRED, the Pacific Islands Benthic Habitat Mapping Center and Davey Jones Locker GIS Laboratory Oregon State University Native_Data_Set_Environment: ArcGIS ASCII file or ArcGIS Grid file, bathymetry derived from 4x4m multispectral satellite imagery (IKONOS) using ENVI 4.5, multibeam and derived bathymetry were integrated using ArcGIS 9.3 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 C/A Horizontal position accuracy: 25 meters Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Range resolution of sonar: varies with depth Raw sounding resolution: varies with depth Vertical accuracy of gridded sonar product: ~ 1% of water depth Vertical accuracy of derived bathymetry product: 5 meter range Lineage: Process_Step: Process_Date: 20090814 Process_Description: Multiple tools in ENVI 4.5 were used to complete the following processing steps: Data conversion from digital number to radiance, correction for atmosphere and water surface reflection, linearization of spectral decay as function of depth, masking of non-applicable values, and bathymetric derivation using variables from multiple linear regression analysis. Multiple tools in ArcGIS 9.3 were used for dataset integration and to extract values for the multiple linear regression analysis and subsequent error analyses. The statisitcs program S-Plus was used for the multiple linear regression analysis to provide original variables for depth derivation. The multivariate slope intercept formula used to derive depth was Depth=Yint+(Mblue)(Xblue)+(Mgreen)(Xgreen). Eight derived products, four from the image alamagan_107146_msi_rat.pix (Ala146) and four from the image alamagan_135475_msi_rat.pix (Ala475), were integrated to expand spatial coverage. The original MLR variables for Ala146 were Yint=15.1542, Mblue=-10.3798, and Mgreen=24.3859. The product derived from these variables (Ala146_DB) was mosaiced with three additional products derived using increasingly reduced Y-intercept values as follows: Yint=11.1542 (Ala146_DB4), Yint=7.1542 (Ala146_DB8), Yint=3.1542 (Ala146_DB12). This was done to increase coverage in shallow areas. More information on this integration process is provided in the product error analysis, availble from PIBHMC upon request. The original MLR variables for Ala475 were Yint=12.0276, Mblue=-6.3664, and Mgreen=16.1327. The product derived from these variables (Ala475_DB) was mosaiced with three additional products derived using increasingly reduced Y-intercept values as follows: Yint=8.0276 (Ala475_DB4), Yint=4.0276 (Ala475_DB8), Yint=0.0276 (Ala475_DB12). This was done to increase coverage in shallow areas. More information on this integration process is provided in the product error analysis, availble from PIBHMC upon request. The derived bathymetry from each image was in turn mosaiced prioritizing the data from Ala146 over Ala475. Data with better statistical accuracy was given higher "priority" so that they replaced concurrent data with lower accuracy during the mosaic process. A detailed description of all processing steps is available at: http://dusk.geo.orst.edu/djl/theses/kyle/Cookbook_042108.pdf An error analysis of each derived bathymetry grid used is available upon request. Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 1212 Column_Count: 1128 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 4.000000 Ordinate_Resolution: 4.000000 Planar_Distance_Units: meters Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 55 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: 147.000000 Latitude_of_Projection_Origin: 0.000000 False_Easting: 500000.000000 False_Northing: 0.000000 Geodetic_Model: Horizontal_Datum_Name: D_WGS_1984 Ellipsoid_Name: WGS_1984 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257224 Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: NOAA PIFSC CRED PIBHMC and DJLab OSU Contact_Person: Kyle Hogrefe Contact_Address: Address_Type: mailing and physical address Address: 104 Wilkinson Hall, Oregon State University City: Corvallis State_or_Province: Oregon Postal_Code: 97331 Country: USA Contact_Voice_Telephone: 541-740-8444 Contact_Electronic_Mail_Address: hogrefek@geo.oregonstate.edu 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: Arc Grid Format_Information_Content: Arc Grid can be opened directly using ArcMap or ArcCatalog. Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://www.soest.hawaii.edu/pibhmc Fees: None Metadata_Reference_Information: Metadata_Date: 20090818 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Organization: NOAA PIFSC CRED PIBHMC and DJLab OSU Contact_Person: Kyle Hogrefe Contact_Address: Address_Type: mailing and physical address Address: 104 Wilkinson Hall, Oregon State University City: Corvallis State_or_Province: Oregon Postal_Code: 97331 Country: USA Contact_Voice_Telephone: 541-740-8444 Contact_Electronic_Mail_Address: hogrefek@geo.oregonstate.edu 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