Coastal Bend Texas Benthic Habitat Mapping Aransas Bay (NODC Accession 0070784)

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Frequently anticipated questions:

What does this data set describe?

Coastal Bend Texas Benthic Habitat Mapping Aransas Bay (NODC Accession 0070784)
In 2006 and 2007 the NOAA Coastal Services Center purchased services to process existing digital multi-spectral imagery (ADS-40) and create digital benthic habitat data from this imagery for selected Texas coastal bend bays. The Center worked cooperatively with the Texas Parks and Wildlife Department (TPWD) and the Texas A and M University Center for Coastal Studies to develop benthic habitat data, primarily Submerged Aquatic Vegetation (SAV) for several coastal bays. This data will support the state's recently adopted Seagrass Monitoring Program which calls for regional mapping of SAV for status and trends assessment. The Center, Texas A and M, and TPWD have coordinated on the requirements of this project.
Benthic habitat vector data was generated over eight Texas Coast study areas. The geographic extent of these Corpus Christi Bay - ~356 mi2 , Redfish Bay - ~62 mi2, Aransas Bay - ~285 mi2, and Copano Bay - ~158 mi2, Lower Laguna Madre - ~800 mi2, Upper Laguna Madre -~313 mi2, Baffin Bay - ~232 mi2, San Antonio Bay - ~370mi2. Benthic habitat data was generated for all estuarine lands below mean high water within the study area. No benthic data was required for the marine side of the barrier beaches.
  1. How should this data set be cited?

    Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Coastal Services Center (CSC), 20070823, Coastal Bend Texas Benthic Habitat Mapping Aransas Bay (NODC Accession 0070784): NOAA's Ocean Service, Coastal Services Center (CSC), Charleston, SC.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -097.074216
    East_Bounding_Coordinate: -096.709414
    North_Bounding_Coordinate: 28.295159
    South_Bounding_Coordinate: 27.827573

  3. What does it look like?

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

    Calendar_Date: 23-Aug-2007
    Currentness_Reference: Publication Date

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

    Geospatial_Data_Presentation_Form: Digital vector data

  6. How does the data set represent geographic features?

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

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      UTM_Zone_Number: 14
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -099.000000
      Latitude_of_Projection_Origin: 00.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000128
      Ordinates (y-coordinates) are specified to the nearest 0.000128
      Planar coordinates are specified in Meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000000000000000.
      The flattening of the ellipsoid used is 1/298.257222096042310000.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview: None
    Entity_and_Attribute_Detail_Citation: Not applicable

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 Coastal Services Center

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

    Fugro EarthData, Inc.
    Attn: Harold Rempel
    Director of Program Management
    7320 Executive Way
    Frederick, MD 21704

    301-948-8550 (voice)
    301-963-2064 (FAX)

    Hours_of_Service: 9:00am - 5:00pm

Why was the data set created?

These data have been created as a result of the need for having geospatial data immediately available and easily accessible in order to enhance the capability of the NOAA Coastal Services Center (CSC)

How was the data set created?

  1. From what previous works were the data drawn?

    GPS Ground Control (source 1 of 2)

    Type_of_Source_Media: paper
    Source_Scale_Denominator: 1000
    TerraSurv, Inc. of Pittsburgh, PA was contracted by EarthData International of Frederick, MD to perform a geodetic control survey in support of mapping an area along the southeasterly coast of Texas between Port Lavaca and Brownsville. Thirty-eight photo identifiable locations were surveyed to provide ground control and quality assurance checks for the mapping. Twenty of the stations were used for mapping control and eighteen of the stations were used for quality checks. The horizontal datum was the North American Datum of 1983, CORS adjustment (NAD 1983 CORS). The vertical datum was the North American Vertical Datum of 1988 (NAVD 1988).

    Imagery (source 2 of 2)
    Geomatics, Northwest, 20041111, 2004 ADS40 Digital NAIP Imagery.

    Type_of_Source_Media: digital
    Source_Scale_Denominator: 900
    The digital orthophotography was developed from imagery acquired as part of the 2004 overflight of the State of Texas developed for the USDA National Agricultural Imagery Program (NAIP). In order to achieve a horizontal accuracy of 5 meters, CE90 it is necessary to reprocess the imagery incorporating new GPS field control. It should be noted that the imagery was not tide coordinated so tidal variation may exist between sorties. The imagery was acquired between November 3, 2004 and November 7,2004.

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

    Date: 09-Aug-2007 (process 1 of 1)
    The original 1m DOQQs for the project area were resampled to 2m and mosaicked. For habitat classification, the mosaicked imagery was divided into six processing one set of six mosaics for true color and one set of six mosaics for color-IR. Image segmentation was performed using on the blue, green, red, and near-infrared bands for each Ethe six processing areas. The classification of the habitat segments (as ESRI polygon shapefiles) was performed using CART analysis. The habitat maps for each of the six areas was refined with the aid of field data collected during May, June, and July 2006 and January 2007. The six processing area shapefiles were edgematched and combined into a single shapefile which was clipped to the final project area boundary and then clipped into six separate shapefiles representing the six bay systems in the project area. Adjacent bay systems do not overlap,resulting in no overlapping habitat polygons across the entire project area. Each polygon, within and across all six bay systems, has a unique polygon identification number. Each shapefile was checked for proper topology and to insure that each polygon has a correct habitat label, habitat code, modifier label if present, unique identification number, and an area calculation. Polygons below the 100m2 minimum mapping unit (MMU) were eliminated, though some polygons less than 100m2 were retained if their area changed to below the MMU due to the polygon boundary smoothing process. The habitat data also went through an independent validation review. Accuracy assessment was performed on seven classes with Patchy SRV and Continuous SRV being combined into a single accuracy class. For field data collection, non-random sites in the form of polygons were chosen by analysts with an attempt to sample all available image signatures. These sites were visited in the field and data on each site was collected directly into digital format (ESRI shapefile) using a laptop or onto a paper form that was later entered into digital format.Sites were navigated to primarily using a Garmin GPS 76unit connected to a Panasonic Toughbook laptop displaying the project imagery and polygons in ArcMapv9.1 or using the GPS unit alone. Habitat classification was estimated as accurately as possible using different methods or combination of methods which included above water observation, snorkeling, wading, and underwater video. This data was entered into an ESRI shapefile via a digital field form in ArcMap specifically developed for this type of field data collection. After collection, sites were classified as either "sand" or "mud" bottom type using Texas Bureau of Economic Geology sediment maps. More sample polygon sites were collected in-office based on the in-field collected sites in order to meet the 50 sites per class per bottom type accuracy assessment requirement.Once all the sites were chosen, they were again divided into "sand" and "mud" bottom types. For each class, per bottom type, a random selector macro in ArcMap was used to randomly select 50 sites for accuracy assessment. The entire pool of accuracy sites was kept separate from the remaining sites and only used for accuracy assessment during the project. Anonymity of the accuracy sites was maintained throughout the project because it was unnecessary to ever visually review these sites in order to perform the accuracy analysis. More accuracy assessment sites were collected in a later field collection trip to add to the analysis. These sites were chosen by randomly selecting polygons within specific regions that were pre-determined to be visited. Information for these sites was collected using the same methods for the other sites. Accuracy information was compiled using ArcMap. Accuracy polygons were transformed into polygon centroid points forced to be located within the polygon. These points were used to select the corresponding polygons in the habitat map. The selected polygons' attributes were joined to the accuracy polygons so that each accuracy polygon had both the accuracy habitat label and its map label. An accuracy assessment error matrix was generated using this information by importing it to Microsoft Excel and building the matrix. Both deterministic and fuzzy accuracy assessment were performed. The accuracy analysis and error matrices are presented and discussed in the project final report entitled Coastal Bend of Texas Benthic Habitat Mapping Phase 1 Final Report.

    Person who carried out this activity:

    Fugro EarthData, Inc.
    Attn: Harold Rempel
    Director of Program Management
    7320 Executive Way
    Frederick, MD 21704

    301-948-8550 (voice)
    301-963-2064 (FAX)

    Hours_of_Service: 9:00am - 5:00pm
    Data sources used in this process:
    • Imagery
    • GPS Ground Control

  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?

    Horizontal accuracy of the reprocessed source imagery was verified to be better than 5 meters at 90% confidence level in accordance with National Map Accuracy Standards for a 1-meter GSD. The thematic accuracy of the habitat maps meet or exceed the minimum acceptable field/map accuracy limits which are 80% for each individual habitat type, and 85% overall for baseline benthic habitat at the SCHEME 2-digit subclass level from a "users," as well as a "producers" perspective as defined by Story and Congalton, 1986.

  2. How accurate are the geographic locations?

    Accuracy assessment determined by evaluating the horizontal accuracy obtained during the aerotriangulation process for each lift for the reprocessed imagery and by field verification for the completed map product.

  3. How accurate are the heights or depths?


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

    Compliance with the accuracy standard for the reprocessed imagery was ensured by the placement of photo identifiable ground control points and the collection of airborne GPS data. Compliance with the accuracy standard for the final map product was ensured by fieldchecks and manual editing.

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

    For the reprocessed imagery, compliance with the accuracy standard was ensured by the placement of photoidentifiable ground control points. A total of 18 photoidentifiable ground survey points was used for the calculations. An RMS value was calculated based on the imagery reprocessed for this project by comparing the aerotriangulated X and Y coordinates. This value represents an estimate of the accuracy of the horizontal coordinate measurements in the tile expressed in meters.For the final map product Initial Map accuracy assessment was used as a tool to prioritize areas for further field examination and after field investigation to prioritize those areas where additional modeling or interpretation was needed. Error matrices showing both deterministic and fuzzy accuracies were compiled for the initial map. Based on the results compiled from the assessment, the team visit any classes exhibiting inaccuracy and addressed the classes through modeling, additional analysis or manual editing.

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: None

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

    NOAA Coastal Services Center
    Attn: Clearinghouse Manager
    2234 South Hobson Avenue
    Charleston, SC 29405-2413

    843-740-1210 (voice)
    843-740-1224 (FAX)

    Hours_of_Service: Monday-Friday, 8-5 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?

    Users must assume responsibility to determine the usability of these data.

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 24-Jan-2017
Metadata author:
NOAA Coastal Services Center
Attn: Metadata Specialist
2234 S Hobson Ave.
Charleston, SC 29405

843-740-1210 (voice)
843-740-1224 (FAX)

Hours_of_Service: 8:00 am to 5:00 pm EST
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.9.13 on Thu Oct 19 09:47:41 2017