Shallow-water Benthic Habitats of the Northwestern Hawaiian Islands from Aggregated Habitat Cover Maps Derived from High Resolution IKONOS Satellite Imagery (Draft)

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Frequently anticipated questions:


What does this data set describe?

Title:
Shallow-water Benthic Habitats of the Northwestern Hawaiian Islands from Aggregated Habitat Cover Maps Derived from High Resolution IKONOS Satellite Imagery (Draft)
Abstract:
Shallow-water, aggregated cover maps were produced by combining as many as four or more detailed habitat types into general cover categories. The original detailed habitat maps were produced by rule-based, semi- automated image analysis of high-resolution satellite imagery for nine locations in the Northwestern Hawaiian Islands. This project is a cooperative effort between the National Oceanic and Atmospheric Administration, State of Hawaii Department of Land and Natural Resources, and the U.S. Fish and Wildlife Service to produce benthic habitat maps and georeferenced imagery for the Northwestern Hawaiian Islands. This project was conducted in support of the U.S. Coral Reef Task Force.
  1. How should this data set be cited?

    National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Remote Sensing Team, 20021231, Shallow-water Benthic Habitats of the Northwestern Hawaiian Islands from Aggregated Habitat Cover Maps Derived from High Resolution IKONOS Satellite Imagery (Draft): NOAA's Ocean Service, National Centers for Coastal Ocean Science (NCCOS), Silver Spring, MD.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -179.00
    East_Bounding_Coordinate: -160.00
    North_Bounding_Coordinate: 29.00
    South_Bounding_Coordinate: 22.00

  3. What does it look like?

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

    Beginning_Date: 2000
    Ending_Date: 2001
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: raster digital data

  6. How does the data set represent geographic features?

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

      Indirect_Spatial_Reference: Northwestern Hawaiian Islands
      This is a Raster data set.

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 1
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -177
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000
      False_Northing: 0.0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 4
      Ordinates (y-coordinates) are specified to the nearest 4
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80, WGS84.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.25.

  7. How does the data set describe geographic features?

    Aggregated Habitat Cover Classification Scheme
    The aggregated habitat cover classification scheme was designed to provide information on substrate (hardbottom or unconsolidated) and habitat cover (coral, Crustose coralline algae, macroalgae/seagrass, or uncolonized) found in the NWHI. (Source: NOS - Biogeography Program)

    Northwestern Hawaiian Islands Classification Scheme
    Benthic features were assigned one of thirty habitat types ranging from sand to coral. A complete description of these classification categories can be found in the NWHI_class_scheme.pdf (<http://ccmaserver.nos.noaa.gov/rsd/products/pdf/NWHI_class_scheme.pdf>).

    RESULTS AGGREGATED COVER TYPE:

    Habitat_name, Numeric_value, Red_color_value, Green_color_value, Blue_color_value

    RESULTS DETAILED HABITAT TYPE:

    Habitat_name, Habitat_classification_code (Source: NOS - Biogeography Team)

    ValueDefinition
    Habitat_nameThe name of the benthic habitat identified and depicted.
    Habitat_classification_codeA hierarchical, 4-digit code assigned to each habitat type.
    Numeric_valueA two- or three-digit numeric value assigned to each habitat type.
    Red_color_valueA numeric value ranging from 0-255 assigned to the red channel of the RGB color palette.
    Green_color_valueA numeric value ranging from 0-255 assigned to the green channel of the RGB color palette.
    Blue_color_valueA numeric value ranging from 0-255 assigned to the blue channel of the RGB color palette

    Hardbottom with >10% live coral, 23, 240, 164, 164
    Included all classes in the hardbottom substrate category that had more than 10 percent live coral cover. Hardbottom that was not classified with respect to structure (class 2020), but which had live coral, was also included in this category. Bottom habitat consisting of mixtures of live coral, crustose coralline algae and macroalgae also dell into this category as long as there was enough live coral to meet the 10 percent threshold. (Source: Aggregated Cover Type)

    ValueDefinition
    Hardbottom with live coral (>10% cover)* (2010)Detailed Habitat Type
    Linear Reef with live coral (>10% cover)* (2110)Detailed Habitat Type
    Aggregated Coral Heads with live coral (>10% cover)* (2210)Detailed Habitat Type
    Patch Reef with live coral (>10% cover)* (2410)Detailed Habitat Type
    Aggregated Patch Reef with live coral (>10% cover)* (2510)Detailed Habitat Type
    Scattered Coral/Rock in sand with live coral (>10% cover)* (2610)Detailed Habitat Type
    Pavement with live coral (>10% cover)* (2710)Detailed Habitat Type
    Pavement with live coral (>10% cover) and dense (>50% cover) algae* (2712)Detailed Habitat Type
    Pavement with sand channels and live coral (>10% cover)* (2810)Detailed Habitat Type
    Volcanic Rock with live coral (>10% cover)* (2910)Detailed Habitat Type

    Hardbottom with >10% crustose coralline algae,29,255,111,111
    Included all classes in the hardbottom substrate category that had more than 10 percent live crustose coralline algal cover, but not more than ten percent live coral cover. Bottom habitats with a mixture of crustose coralline algae, live coral (not more than 10 percent) and macroalgae fell in this category if there was enough crustose coralline algae to meet the 10 percent threshold. (Source: Aggregated Cover Type)

    ValueDefinition
    Hardbottom with crustose coralline algae (>10% cover)* (2030)Detailed Habitat Type
    Linear Reef with crustose coralline algae (>10% cover)* (2130)Detailed Habitat Type
    Patch Reef with crustose coralline algae (>10% cover)* (2430)Detailed Habitat Type
    Pavement with crustose coralline algae (>10% cover)* (2730)Detailed Habitat Type

    Hardbottom (uncolonized),26,150,150,150
    Included all classes in the hardbottom substrate category that had less than 10 percent live coral cover, crustose coralline algal cover or macroalgal cover. (Source: Aggregated Cover Type)

    ValueDefinition
    Hardbottom, uncolonized* (2020)Detailed Habitat Type
    Linear Reef, uncolonized* (2120)Detailed Habitat Type
    Patch Reef, uncolonized* (2420)Detailed Habitat Type
    Pavement, uncolonized* (2720)Detailed Habitat Type
    Pavement with sand channels, uncolonized* (2820)Detailed Habitat Type
    Volcanic Rock, uncolonized* (2920)Detailed Habitat Type

    Hardbottom with >10% macroalgae,22,240,164,164
    Included all classes in the hardbottom substrate category that had more than 10 percent macroalgae, but not more than 10 percent live coral cover or 10 percent crustose coralline algal cover. Typically these habitats also had a high percentage of turf algal cover. (Source: Aggregated Cover Type)

    ValueDefinition
    Hardbottom with sparse (10-50% cover) algae* (2001)Detailed Habitat Type
    Linear Reef, uncolonized with sparse (10-50% cover) algae* (2121)Detailed Habitat Type
    Patch Reef, uncolonized with sparse (10-50% cover) algae* (2421)Detailed Habitat Type
    Pavement with sparse (10-50% cover) algae* (2701)Detailed Habitat Type
    Pavement with dense (>50% cover) algae* (2702)Detailed Habitat Type
    Pavement with live coral (>10% cover) and dense (>50% cover) algae* (2712)Detailed Habitat Type
    Pavement, uncolonized with dense (>50% cover) algae* (2722)Detailed Habitat Type

    Hardbottom with indeterminate cover,20,120,120,120
    Included all classes in the hardbottom substrate category for which a specific bottom cover was not identified. Included were area classified only to the first or second level of the detailed classification scheme. (Source: Aggregated Cover Type)

    ValueDefinition
    Hardbottom* (2000)Detailed Habitat Type
    Linear Reef* (2100)Detailed Habitat Type
    Spur and Groove* (2300)Detailed Habitat Type
    Individual Patch Reef* (2400)Detailed Habitat Type
    Aggregated Patch Reef* (2500)Detailed Habitat Type
    Pavement* (2700)Detailed Habitat Type
    Volcanic Rock* (2900)Detailed Habitat Type
    Pavement with Sand Channels* (2800)Detailed Habitat Type

    Unconsolidated with 10% or less macroalgae or seagrass,10,229,207,95
    Included all classes in the unconsolidated substrate category with not more than 10 percent cover of live submerged vegetation (macroalgae/seagrass). (Source: Aggregated Cover Type)

    ValueDefinition
    Unconsolidated sediment* (1000)Detailed Habitat Type
    Sand* (1100)Detailed Habitat Type
    Unconsolidated rubble* (1300)Detailed Habitat Type
    Sand and rubble* (1400)Detailed Habitat Type
    Groove* (1500)Detailed Habitat Type

    Unconsolidated with >10% macroalgae or seagrass,220,0,128,64
    Included all classes in the unconsolidated substrate category with more than 10 percent cover of live submerged vegetation (macroalgae/seagrass). Seagrass was very uncommon in NWHI (only a small area was found at Midway during the field survey) and was not identified on any of the habitat maps. (Source: Aggregated Cover Sites)

    ValueDefinition
    Sand with macroalgae* (1120)Detailed Habitat Type
    Sand with patchy (10-50% cover) macroalgae* (1121)Detailed Habitat Type
    Sand with dense (>50% cover) macroalgae* (1122)Detailed Habitat Type
    Unconsolidated Rubble with sparse (10-50% cover) algae* (1301)Detailed Habitat Type
    Unconsolidated Rubble with dense (>50% cover) algae* (1302)Detailed Habitat Type

    Deep water,240,0,70,130
    Areas where the bottom cannot be detected (identified) in the imagery. In most cases, this occurs in water more than 30 m deep. (Source: NOS - Biogeography Program)

    User defined - Detailed Habitat Type

    Land,250,170,115,0
    Areas determined to be above the water line in the imagery at the time the imagery was acquired. (Source: NOS - Biogeography Program)

    User defined - Detailed Habitat Type

    Unclassified (e.g., cloud, cloud shadow, surf),255,70,0,80
    Areas where the bottom type is unclassified because of turbidity in the water, surface glint, or other types of interference. This category also includes areas where the seabed cannot be classified due to a lack of supplemental field-based information of for other reasons. (Source: NOS - Biogeography Program)

    User defined - Detailed Habitat Type

    No Data,4000,0,0,0
    Referes to areas within the geographic bounds of the habitat map that lie outside the bounds of the aquired imagery. This is not a habitat category in the classification scheme. (Source: NOS - Biogeography Program)

    User defined


Who produced the data set?

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

  2. Who also contributed to the data set?

    NOAA, University of Hawaii, U.S. Fish and Wildlife Service

  3. To whom should users address questions about the data?

    National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Remote Sensing Team
    Remote Sensing Specialist
    1305 East West Highway, N/SP
    Silver Spring, Maryland 20910

    301-713-3028 (voice)
    301-713-4384 (FAX)
    Richard.Stumpf@noaa.gov

    Hours_of_Service: Monday to Friday, 0800 -1700, EST


Why was the data set created?

The National Ocean Service is conducting research to digitally map biotic resources and coordinate a long-term monitoring program that can detect and predict change in U.S. coral reefs, and their associated habitats and biological communities. This project was conducted in support of the U.S. Coral Reef Task Force (<http://coralreef.gov>).


How was the data set created?

  1. From what previous works were the data drawn?

    NOAA/NOS/benthic characterization data (source 1 of 1)
    Imaging, Space, 2002, IKONOS Panchromatic and Multispectral Imagery for the Northwestern Hawaiian Islands: Space Imaging, Thornton, CO.

    Other_Citation_Details:
    Acquisition_Date: Gardner Pinnacles (2 swaths; 20001014) Acquisition_Date: Kure Atoll (2 swaths; first acquisition; 20001120) Acquisition_Date: Kure Atoll (2 swaths; second acquisition; 20010926) Acquisition_Date: Laysan Island (swaths 1 and 3; 20010124) Acquisition_Date: Laysan Island (swath 2; 20010215) Acquisition_Date: French Frigate Shoals (first acquisition; 4 swaths; 20001011) Acquisition_Date: French Frigate Shoals(second acquisition; swaths 1, 2, and 3; 20010911) Acquisition_Date: French Frigate Shoals (second acquisition; swath 4; 20010919) Acquisition_Date: Midway Atoll (swath 1; 20010122) Acquisition_Date: Midway Atoll (swath 2; 20010318) Acquisition_Date: Lisianski Island (3 swaths; 20001012) Acquisition_Date: Nihoa (swath 1; 20010109) Acquisition_Date: Nihoa (swath 2; 20010120) Acquisition_Date: Nihoa (swath 3; 20010418) Acquisition_Date: Pearl and Hermes Atoll (3 swaths; 20010119) Acquisition_Date: Maro Reef (3 swaths; 20010724) Acquisition_Date: Necker Island (2 swaths; 20010126)
    Type_of_Source_Media: IKONOS high-resolution satellite imagery
    Source_Contribution:
    High resolution satellite imagery was analyzed to produce benthic habitat maps of the Northwestern Hawaiian Island.

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

    Date: 2002 (process 1 of 1)
    High-resolution satellite imagery was analyzed using rule-based, semi-automated, digital image analysis techniques to produce benthic habitat maps of the Northwestern Hawaiian Island. Shallow-water, aggregated habitat cover maps were produced by combining (aggregating) as many as four or more detailed habitat categories into generalized cover habitat types. The list of these aggregated cover types and those detailed habitat categories included in each aggregation are presented below. Following careful evaluation of the digital satellite imagery, selected sites were visited in the field for typological validation. This validation included: (1) areas in the satellite imagery with confusing or difficult to interpret spectral signatures, (2) transects across many representative habitat types occurring in different depths and water conditions, (3) a survey of the Zones, and (4) confirmation of preliminary habitat delineations after a first draft habitat map was produced. Navigating to field sites was accomplished in a variety of ways including uploading position coordinates from the mosaic into an onboard GPS and navigating to those waypoints, using an onboard PC connected to GPS allowing navigation using digital nautical charts or the mosaic, and visual navigation using landmarks visible in the satellite imagery. On most occasions, field activities were conducted with the guidance of local experts. Satellite imagery was used in the field to facilitate comparison of signatures in the imagery to actual habitats at each site. Individual sites were visually evaluated by snorkeling and free diving or directly from the boat in shallow, clear water. Habitat transitions were evaluated by swimming transects across habitat types to further guide placement of habitat boundaries. Habitat type(s), zone, approximate depth, position (GPS), image number, and other descriptive information were recorded at each site. Field data for each site were then compiled into a text table with GPS position fields to allow overlay of the field information on the mosaic and habitat maps. Where depth and water clarity permitted, the satellite images were used to navigate across multiple bottom features allowing continuous confirmation of habitat types and transitions between each site.

    Person who carried out this activity:

    National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Remote Sensing Team
    Remote Sensing Specialist
    1305 East West Highway, N/SP
    Silver Spring, Maryland 20910

    301-713-3028 (voice)
    301-713-4384 (FAX)
    Richard.Stumpf@noaa.gov

    Hours_of_Service: Monday to Friday, 0800 -1700, EST
  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?

    Statistical analysis to determine accuracy was performed using a subset of the 1,130 site specific benthic characterization data (376 points were used in the accuracy assessment) available for the NWHI. The overall accuracy of the aggregated cover maps was 72 percent (Kappa Statistic 0.59, Tau Coefficient 0.62), and ranged from 94 percent accuracy for unconsolidated sediment with little or no algae or seagrass to 9% for unconsolidated sediment with seagrass present. Correctly classifying benthic habitats that include algae and live coral was challenging. For example, it is difficult to separate Unconsolidated Rubble with dense (>50 percent cover) algae from Pavement with dense (>50 percent cover) algae. Also, it is difficult to separate Unconsolidated Rubble and Sand and Rubble from Pavement habitats. These challenges also were encountered when differentiating between the various habitats with live coral cover. The aggregated cover category Hardbottom with indeterminate cover was not included in the accuracy assessment. The aggregated Hardbottom with indeterminate cover includes those detailed habitat categories where a specific cover was not identified on the map, and no comparison to the field-based benthic characterization information could be performed. An assessment of the overall accuracy of the hardbottom and unconsolidated was performed. That analysis included habitat categories with indeterminate cover and their associated field-based benthic characterization data. That analysis revealed that these two habitats were correctly identified 82% and 90% of the time respectively.

  2. How accurate are the geographic locations?

    Kure Atoll, Midway Atoll, Pearl and Hermes Atoll, Lisianski Island, Laysan Island, French Frigate Shoals, and Nihoa Island are positioned to within five (5) meters at sea level. Necker Island is positioned to within 15 meters at sea level. Maro Reef is positioned to within eight (8) meters at sea level. Spatial data meets or exceeds national map accuracy standards for fixed features.

  3. How accurate are the heights or depths?

    none reported

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

    High-resolution satellite imagery was analyzed using rule-based, semi-automated, digital image analysis techniques to produce benthic habitat maps of the Northwestern Hawaiian Island. In total, 1,130 site specific examples of the spectral and spatial characteristics of differing habitats were available and incorporated into the analysis process for the NWHI. The minimum mapping unit (MMU) for identifying habitats or features was 100 sq. m. Generally, features to a depth of approximately 30 m can be analyzed from the satellite imagery. Due to the depth of water surrounding Gardner Pinnacles, very little characterization of the benthic habitats of Gardner Pinnacles was possible. No satellite imagery was available for Gambia shoals.

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

    Multispectral satellite imagery was positioned using National Geodetic Survey ground control data for Kure Atoll, Midway Atoll, Pearl and Hermes Atoll, Lisianski Island, Laysan Island, French Frigate Shoals, and Nihoa Island. Satellite imagery of Necker Island was positioned using satellite ephemeris data. Satellite imagery of Maro Reef was positioned using a combination of satellite ephemeris data and supplemental bathymetry transect data. Once maps were positioned, validation was performed by comparison to repositioned vector shoreline data depicted on recently-revised NOS nautical charts. The draft classified benthic habitat maps were reviewed by scientists in Hawaii with first-hand local knowledge of the Northwestern Hawaiian Islands. Comments were received and incorporated into draft maps. Draft maps also underwent a statistics-based accuracy assessment.


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 maps are NOT to be used for navigation. These aggregated cover maps of the shallow-water benthic habitats of the Northwestern Hawaiian Islands have been reviewed by numerous decision makers and scientists familiar with the Northwestern Hawaiian Islands region. Although they represent the best available characterizations of the shallow-water coral reef ecosystems of this region the maps should be considered DRAFT versions.

  1. Who distributes the data set? (Distributor 1 of 1)

    National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Remote Sensing Team
    Remote Sensing Specialist
    1305 East West Highway, N/SP
    Silver Spring, Maryland 20910

    301-713-3028 (voice)
    301-713-4384 (FAX)
    Richard.Stumpf@noaa.gov

    Hours_of_Service: Monday to Friday, 0800 -1700, EST
  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    Not to be used for navigation.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 18-Sep-2014
Metadata author:
National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Remote Sensing Team
Remote Sensing Specialist
1305 East West Highway, N/SP
Silver Spring, Maryland 20910

301-713-3028 (voice)
301-713-4384 (FAX)
Richard.Stumpf@noaa.gov

Hours_of_Service: Monday to Friday, 0800 -1700, EST
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)


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