1992 Seagrass and Mangrove Habitats of the Salt River Bay National Historical Park and Ecological Preserve, St Croix, USVI

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Frequently anticipated questions:


What does this data set describe?

Title:
1992 Seagrass and Mangrove Habitats of the Salt River Bay National Historical Park and Ecological Preserve, St Croix, USVI
Abstract:
Habitat maps were created as part of a larger ecological assessment conducted by NOAA's National Ocean Service (NOS), Biogeography Program, for Salt River Bay National Historic Park and Ecological Preserve (National Park Service). Aerial photographs were obtained for 1992 from the National Geodetic Survey, and were orthorectified by the Biogeography Program. A classification scheme was set up with 20 benthic habitat types, 19 land cover types, and 13 mangrove habitat types. For this map of seagrass and mangrove habitats during 1992 only the 3 seagrass, and 14 mangrove classification categories were used. These were mapped directly into a GIS system through visual interpretation of orthorectified aerial photographs.
Supplemental_Information:
Coordinate Units are decimal degrees Geodetic Model Horizontal Datum Name is North American Datum of 1983 Ellipsoid Name is Geodetic Reference System 80 Semi-major Axis is 6378206.400000 Denominator of Flattening Ratio is 294.978698
  1. How should this data set be cited?

    Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Biogeography Program, 2004, 1992 Seagrass and Mangrove Habitats of the Salt River Bay National Historical Park and Ecological Preserve, St Croix, USVI: NOAA's Ocean Service, National Centers for Coastal Ocean Science (NCCOS), Silver Spring, MD.

    Online Links:

    This is part of the following larger work.

    Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Biogeography Program, 2004, An Ecological Characterization of Salt River Bay National Historic Park and Ecological Preserve.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -64.761931
    East_Bounding_Coordinate: -64.750033
    North_Bounding_Coordinate: 17.783290
    South_Bounding_Coordinate: 17.765249

  3. What does it look like?

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

    Calendar_Date: 31-Jan-1992
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

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

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • G-Polygon (263)

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

  7. How does the data set describe geographic features?

    SARI_1992_sg_mang
    Shapefile Attribute Table (Source: User defined)

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    UNIQUEID
    ID assigned to each habitat type (Source: software defined)

    ValueDefinition
    1Benthic/Artificial
    2Benthic/Coral Reef and Hardbottom/Coral Reef and Colonized Hardbottom/Aggregated Patch Reefs
    3Benthic/Coral Reef and Hardbottom/Coral Reef and Colonized Hardbottom/Colonized Bedrock
    4Benthic/Coral Reef and Hardbottom/Coral Reef and Colonized Hardbottom/Colonized Pavement
    5Benthic/Coral Reef and Hardbottom/Coral Reef and Colonized Hardbottom/Colonized Pavement with Sand Channels
    7Benthic/Coral Reef and Hardbottom/Coral Reef and Colonized Hardbottom/Linear Reef
    8Benthic/Coral Reef and Hardbottom/Coral Reef and Colonized Hardbottom/Scattered Coral/Rock in Unconsolidated Sediment
    9Benthic/Coral Reef and Hardbottom/Coral Reef and Colonized Hardbottom/Spur and Groove
    10Benthic/Coral Reef and Hardbottom/Uncolonized Hardbottom/Reef Rubble
    11Benthic/Coral Reef and Hardbottom/Uncolonized Hardbottom/Uncolonized Bedrock
    12Benthic/Coral Reef and Hardbottom/Uncolonized Hardbottom/Uncolonized Pavement
    14Benthic/Submerged Vegetation/Macroalgae/Patchy (Discontinuous) - 50% to less than 90% cover
    15Benthic/Submerged Vegetation/Macroalgae/Patchy (Discontinuous) - 10% to less than 50% cover
    16Benthic/Submerged Vegetation/Macroalgae/Continuous - 90% to 100% cover
    32Benthic/Unconsolidated Sediments/Mud
    33Benthic/Unconsolidated Sediments/Sand
    34Benthic/Unknown
    37Land/Bare Areas/Other
    38Land/Bare Areas/Rock
    39Land/Bare Areas/Sand/Beach
    40Land/Bare Areas/Soil
    41Land/Developed/Commercial
    46Land/Inland Water Bodies/Freshwater Pond
    47Land/Inland Water Bodies/Saltwater Pond
    49Land/Natural & Semi-Natural Areas/Forest/Trees/Sparse - 1%-15% canopy coverage
    50Land/Natural & Semi-Natural Areas/Forest/Trees/Open - 15%-65% canopy coverage
    51Land/Natural & Semi-Natural Areas/Forest/Trees/Closed - >65% canopy coverage
    52Land/Natural & Semi-Natural Areas/Shurbs/Bushes/Sparse - 1%-15% canopy coverage
    53Land/Natural & Semi-Natural Areas/Shurbs/Bushes/Open - 15%-65% canopy coverage
    54Land/Natural & Semi-Natural Areas/Shurbs/Bushes/Closed - >65% canopy coverage
    55Land/Natural & Semi-Natural Areas/Vegetated Field
    56Land/Roads/Paved
    57Land/Roads/Unpaved
    58Mangrove/Avicennia germanis/Closed - >65% canopy cover
    59Mangrove/Avicennia germanis/Open - 15%-65% canopy coverage
    60Mangrove/Avicennia germanis/Sparse - 1%-15% canopy coverage
    61Mangrove/Dead
    62Mangrove/Laguncularia racemosa/Closed - >65% canopy cover
    63Mangrove/Laguncularia racemosa/Open - 15%-65% canopy coverage
    64Mangrove/Laguncularia racemosa/Sparse - 1%-15% canopy coverage
    65Mangrove/Mixed/Closed - >65% canopy cover
    66Mangrove/Mixed/Open - 15%-65% canopy coverage
    67Mangrove/Mixed/Sparse - 1%-15% canopy coverage
    68Mangrove/Rhizophora mangle/Closed - >65% canopy cover
    69Mangrove/Rhizophora mangle/Open - 15%-65% canopy coverage
    70Mangrove/Rhizophora mangle/Sparse - 1%-15% canopy coverage
    71Benthic/Submerged Vegetation/Seagrass/Patchy (Discontinuous) - 10% to less than 50% cover
    72Benthic/Submerged Vegetation/Seagrass/Patchy (Discontinuous) - 50% to less than 90% cover
    73Benthic/Submerged Vegetation/Seagrass/Continuous - 90% to 100% cover
    74Land/Developed/Residential

    LOCATION
    Top level habitat classification category (Source: user defined)

    refer to classification scheme

    HABITAT
    Second level habitat classification category (Source: user defined)

    refer to classification scheme

    TYPE
    Third level habitat classification category (Source: user defined)

    refer to classification scheme

    MODIFIER1
    Fourth level habitat classification cateogry (Source: user defined)

    refer to classification scheme

    REC
    Unique ID given to each individual polygon (Source: user defined)

    refer to classification scheme

    AREA
    Area of each polygon in square meters (Source: ESRI defined)

    variable


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?

    Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Biogeography Program

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

    Department of the Interior (DOI), National Park Service (NPS), Salt River Bay National Historic Park and Ecological Preserve
    National Park Service (NPS)
    Christiansted, St. Croix, U.S. Virgin Islands 00820-4611

    (340) 773-1460 (voice)
    zandy_hillis-starr@nps.gov


Why was the data set created?

These maps were created to support current and future monitoring and management efforts of the National Park Service (NPS) for this site, and support the programmatic objectives of the NPS service-wide Inventory and Monitoring Program. In particular, maps created from the time series of the photographs cover periods both before and after Hurricane Hugo (1989), providing insight to habitat changes that occurred following the disaster.


How was the data set created?

  1. From what previous works were the data drawn?

    Benthic Habitats of Puerto Rico and the U.S. Virgin Islands (source 1 of 3)
    Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Biogeography Program, 2001, Benthic Habitats of Puerto Rico and the U.S. Virgin Islands: NOAA's Ocean Service, National Centers for Coastal Ocean Science (NCCOS), Silver Spring, MD.

    Online Links:

    Other_Citation_Details:
    This project is a cooperative effort between the National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal Monitoring and Assessment, the United States Geological Survey, the National Park Service, and the National Geophysical Data Center, to produce benthic habitat maps and georeferenced imagery for Puerto Rico and the U.S. Virgin Islands. This project was conducted in support of the U.S. Coral Reef Task Force.

    Twenty-one distinct benthic habitat types within eight zones were mapped directly into a GIS system using visual interpretation of orthorectified aerial photographs. Benthic features were mapped that covered an area of 1600 km^2. In all, 49 km^2 of unconsolidated sediment, 721 km^2 of submerged vegetation, 73 km^2 of mangroves, and 756 km^2 of coral reef and colonized hardbottom were mapped.

    Type_of_Source_Media: CD-ROM
    Source_Contribution:
    This document identifies the benthic habitat types attributed in this data set.

    Habitat Digitizer (source 2 of 3)
    Buja, Ken, 2001, ArcView Habitat Digitizer Extension v 3.1: NOAA's Ocean Service, National Centers for Coastal Ocean Science (NCCOS), Silver Spring, MD.

    Online Links:

    Type_of_Source_Media: computer program
    Source_Contribution:
    This ArcView extension was used to digitize and attribute benthic zones and habitats for Puerto Rico and the U.S. Virgin Islands.

    NGS aerial photos (source 3 of 3)
    National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Geodetic Survey (NGS), 1992, NGS Color Aerial Photography: MD, Silver Spring.

    Other_Citation_Details:
    These photographs were mosaiced and georeferenced by NOAA's National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Biogeography Program
    Type_of_Source_Media: aerial photography and scanned photographs
    Source_Contribution:
    Benthic features were interpreted and mapped from NGS aerial photos of the Salt River Bay region of aerial photographs of St. Croix, U.S.V.I.

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

    Date: 2004 (process 1 of 1)
    Benthic habitat maps were digitized by delineating habitat boundaries from georeferenced imagery loaded into ArcView 3.2 GIS software with the Image Analysis extension and NOAA Coral Reef Habitat Digitizing extensions both activated. On-screen digitizing was conducted with the minimum mapping unit (MMU) set to 100 square meters and the image scale at 1:1500.

    During the digitizing process, image stretches and manipulation of image contrast, brightness and color balance were performed in the ArcView Image Analysis Extension to enhance features in the processed imagery. Additional collateral information, including previously completed habitat maps, NOS nautical charts, and other descriptive references dealing with benthic and coastal habitats of Salt River National Historic Park and Ecological Preserve was used to assist with image interpretation.

    A first draft map was completed and features in the imagery where uncertainties existed, due to confusing or difficult to interpret signatures, were identified for future ground validation effort. Since maps where based on historical imagery that didn't necessarily reflect current ground condition, similar signatures were identified in year 2000 aerial photographs. An ArcView GIS point theme was generated with points positioned on the features of uncertain habitat type or along transects through gradients between habitat types. The GIS points were converted to GPS waypoints, and were visited for on the ground habitat validation.

    Benthic habitat characterization was conducted at each site by snorkeling, free diving, or via observations from the surface where water depth and clarity permitted. Mangrove habitat characterization was conducted by driving, kayaking or hiking to points and visually identifying mangrove type and cover. GPS data was collected at each location, and site ID, depth, habitat type, and the method used to make the assessment were recorded. The ground validation data was incorporated into the second draft of each map.

    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), Biogeography Program
    Biogeography Team Leader, Mapping Manager
    1305 East West Highway
    Silver Spring, MD 20910

    301-713-3028 (voice)
    301-713-4388 (FAX)
    steve.rohmann@noaa.gov

  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?

    Methods used to create this map were similar to those used to maps of the U.S. Virgin Islands and Puerto Rico by the same office ("Benthic Habitat Maps of Puerto Rico and the U.S. Virgin Islands", 2001). An accuracy assessment conducted for the original maps was designed to determine the accuracy of maps generated from on-screen digitizing using the ArcView Habitat Digitizer Extension. Benthic habitat maps exhibited an overall accuracy of 93.6 percent (Kappa 0.90-0.93) for on-screen digitizing.

    In comparison, the map described here was created from higher resolution imagery (25 microns), finer minimum mapping unit (MMU) (100 square meters), and habitat delineation occurred at a smaller image scale (1:1500). A greater number of ground truth points over more habitat types were verified for the year 2000 mapping data, in a study site of much smaller area. Ground truth points could not be taken for the 1992 data directly, however, year 2000 points were referenced when appropriate. Mapping methods were otherwise the identical to those used previously. Attribute accuracy was therefore presumed to be equivalent to or better than that of the previous map, although a formal assessment was not conducted on the current map directly.

  2. How accurate are the geographic locations?

    The Minimum Mapping Unit (MMU) restriction was set to 100 square meters and digitizing was conducted at 1:1500 scale. Polygons were digitized directly from georegistered orthophotos with spatial accuracy approximately 1.0 meter. These maps represent conditions at the time the aerial photographs were obtained. When considering horizontal map accuracy, it is important to keep in mind that the ocean floor is a dynamic environment. Physical factors such as currents, erosion, and hurricanes and biological factors such as seasonal growth and die-off, affect the distribution and stability of terrestrial, mangrove and benthic habitats in this environment.

  3. How accurate are the heights or depths?

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

    Delineation of all habitat boundaries was conducted with the image scale at 1:1500. All polygons were digitized at this scale except when subtle habitat boundaries were not easily discernable at 1:1500 and zooming out to a more broad scale was required to place boundaries correctly. Digitizing at a uniform scale ensures that the level of detail produced by the photointerpreter is consistent throughout the project.

    The Minimum Mapping Unit (MMU) for identifying habitats or features was 100 square meters for visual photointerpretation. The software utilized in this project was designed to alert the photointerpreter each time a polygon was drawn smaller than the MMU. When this occurred, the photointerpreter has the choice of weather to include the polygon in the dataset or not.

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

    Individual color aerial photographs from 1992 were georeferenced and mosaiced. Approximately 10-15 ground control points were used to orthorectify the mosaic. During the digitizing process, image stretches and manipulating image contrast, brightness and color balance were performed in the ArcView Image Analysis Extension to enhance features in the processed imagery. Additional, collateral information including previously completed habitat maps, NOS nautical charts, and other descriptive references dealing with benthic and coastal habitats of St. Croix were used to assist with image interpretation. Over 200 ground truth points were also checked with year 2000 imagery to verify photographic signature with habitat interpretation. Though 1992 habitats could not be directly verified in the same fashion, where appropriate, collateral information from the year 2000 points was considered during 1992 habitat deliniation.

    GIS topologic quality was established by executing ArcView extension routines that check for: overlapping polygons, multipart polygons, sliver polygons and void polygons. Additionally, checks for adjacent polygons with the same habitat attributes were completed. All errors were identified and corrected. This file is believed to be logically consistent.


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: Not for Navigation

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

    Department of the Interior (DOI), National Park Service (NPS), Salt River Bay National Historic Park and Ecological Preserve
    National Park Service (NPS)
    Christiansted, St. Croix, U.S. Virgin Islands 00820-4611

    (340) 773-1460 (voice)
    zandy_hillis-starr@nps.gov

  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    The National Oceanic and Atmospheric Administration (NOAA) National Centers for Coastal Ocean Science (NCCOS) produced this data for Salt River Bay National Historic Park and Ecological Preserve (NPS). NCCOS Biogeography Program does not guarantee the accuracy of the geographic features or attributes. Please see the metadata records for each data set for complete information on the source, limitations, and proper use.

    Disclaimer- While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 18-Dec-2012
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), Biogeography Program
Attn: Lynn Takata
1305 East-West Highway
Silver Spring, MD 20910

301-713-3028 (voice)
301-713-4388 (FAX)
Lynn.Takata@noaa.gov

Hours_of_Service: 8 a.m. - 4:30 p.m. EST
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)


Generated by mp version 2.9.13 on Sun Dec 21 10:40:58 2014