Digital image mosaic of the nearshore coastal waters of Portlock on the island of O'ahu generated using aerial photographs and SHOALS airborne lidar bathymetry data

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Frequently anticipated questions:


What does this data set describe?

Title:
Digital image mosaic of the nearshore coastal waters of Portlock on the island of O'ahu generated using aerial photographs and SHOALS airborne lidar bathymetry data
Abstract:
This portion of the data release contains a digital image mosaic with 1.0 foot-per-pixel (0.3048 meter-per-pixel) resolution of the Portlock area on the southeast coast of O'ahu. This image mosaic was generated using digitized 1:10K natural color photographs collected by the National Oceanic and Atmospheric Administration (NOAA) National Ocean Service. Also available is a lower-resolution 'browse' graphic of the image mosaic area and associated metadata.
Supplemental_Information:
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  1. How might this data set be cited?
    Pat S. Chavez, Jr., Isbrecht, JoAnn, Velasco, Miguel G., and Cochran, Susan A., 2016, Digital image mosaic of the nearshore coastal waters of Portlock on the island of O'ahu generated using aerial photographs and SHOALS airborne lidar bathymetry data: data release 10.5066/F7NZ85SK, U.S. Geological Survey, Coastal and Marine Geology Program, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Pat S. Chavez, Jr., Isbrecht, JoAnn, Velasco, Miguel G., and Cochran, Susan A., 2016, Digital image mosaic of the nearshore coastal waters of Portlock on the island of O'ahu generated using aerial photographs and SHOALS airborne lidar bathymetry data: data release 10.5066/F7NZ85SK, U.S. Geological Survey, Coastal and Marine Geology Program, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -157.725
    East_Bounding_Coordinate: -157.685
    North_Bounding_Coordinate: 21.294
    South_Bounding_Coordinate: 21.252
  3. What does it look like?
    portlock_1m_browse.jp2 (JPEG 2000)
    10x compression
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 1999
    Ending_Date: 2000
    Currentness_Reference:
    ground condition at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Raster digital data set
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 15070 x 13825, type Pixel
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 4
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -153
      Latitude_of_Projection_Origin: 0
      False_Easting: 0
      False_Northing: 0
      Planar coordinates are encoded using Coordinate Pair
      Abscissae (x-coordinates) are specified to the nearest 1.0
      Ordinates (y-coordinates) are specified to the nearest 1.0
      Planar coordinates are specified in meters
  7. How does the data set describe geographic features?

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Pat S. Chavez, Jr.
    • JoAnn Isbrecht
    • Miguel G. Velasco
    • Susan A. Cochran
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: Susan A. Cochran
    Geologist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7545 (voice)
    831-427-4748 (FAX)
    scochran@usgs.gov

Why was the data set created?

The lack of geographic and thematic maps of coral reefs limits our understanding of reefs and our ability to assess change. The U.S. Geological Survey (USGS) has the capability to compile digital image mosaics that are useful for creating detailed map products. Image maps covering the shallow near-shore coastal waters have been produced for several of the main Hawaiian Islands, including Hawai'i, Maui, Moloka'i, and O'ahu and are presented in JPEG2000 (.jp2) format.

How was the data set created?

  1. From what previous works were the data drawn?
    aerial (source 1 of 3)
    National Oceanic and Atmospheric Administration (NOAA) National Ocean Service, 2000, 1:10K natural-color aerial photographs of selected areas of the island of O'ahu: NOAA National Ocean Service, Silver Spring, MD.

    Type_of_Source_Media: paper aerial photographs
    Source_Contribution:
    Aerial photographs were digitized and used to create image mosaics
    DRG (source 2 of 3)
    U.S. Geological Survey (USGS), 2016, USGSS National Map online database: U.S. Geological Survey (USGS), Reston, VA.

    Online Links:

    Type_of_Source_Media: GeoPDF
    Source_Contribution:
    Digital raster graphics (DRGs) were matched and combined with lidar data to get image-to-image geometric control points on both land and within the water areas to create 'masters' with which to georeferenced the aerial photographs
    lidar (source 3 of 3)
    U.S. Army Corps of Engineers (USACE) Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBCTX), 2000, SHOALS lidar bathymetry data: U.S. Army Corps of Engineers (USACE), Mobile, AL.

    Online Links:

    Type_of_Source_Media: ASCII xyz data
    Source_Contribution:
    Lidar bathymetry data were used to help geometrically control the aerial photography and to create shaded-relief images
  2. How were the data generated, processed, and modified?
    Date: 2007 (process 1 of 1)
    Digital-image mosaics were generated by first scanning 1:10K aerial photographs at 1 foot-per-pixel (0.3048 meter-per-pixel) resolution. The individually scanned digital images were tone- and color-matched and then combined together using spatial matching. Separately, black and white digital raster graphics (DRGs) of the same areas were then combined with shaded-relief images generated from lidar bathymetry data. The resulting black and white shaded-relief images covering both near-shore coastal waters and on-land areas became the geometric 'masters' for the mosaics generated from the aerial photographs. The aerial-photograph mosaics were geometrically corrected to overlay the master data set by using hundreds of image-to-image geometric control points and 'slaving' the mosaic onto the DRG-lidar master. Person who carried out this activity:
    U.S. Geological Survey, Western Geographic Science Center
    Attn: Miguel G. Velasco
    Geographer
    2255 N. Gemini Drive
    Flagstaff, AZ

    928-556-7224 (voice)
    mvelasco@usgs.gov
    Data sources used in this process:
    • all sources cited were used
  3. What similar or related data should the user be aware of?
    Pat S. Chavez, Jr., 1984, U.S. Geological Survey mini image processing system (MIPS): Open-File Report 84-880, U.S. Geological Survey, Reston, VA.

    Online Links:


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    There are no attributes associated with JPEG2000 images.
  2. How accurate are the geographic locations?
    A formal accuracy assessment of the horizontal positional information in the data set has not been conducted.
  3. How accurate are the heights or depths?
    A formal accuracy assessment of the vertical positional information in the data set has not been conducted.
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    No formal logical accuracy tests were conducted, nor are they applicable for these data.

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:
USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? These digital image mosaics are available in JPEG 2000 format (.jp2), along with a lower-resolution 'browse' image and associated metadata.
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    These data can be read by computers running Windows, Macintosh, and UNIX operating systems, all equipped with a color monitor. A PC should have an Intel® Pentium® processor or faster, Microsoft® Windows 98 or newer, and 64 MB of RAM or greater. A Macintosh should have a PowerPC® processor or faster, Mac OS software version 8.6 or newer, and 64 MB of RAM or greater. Almost any UNIX workstation can read these files. Optional software includes Geographic Information System (GIS) software, such as Esri ArcGIS®, or other image-processing software that will handle large files, such as ERDAS®, ENVI®, and Adobe Photoshop® or LizardTech® Express View.

Who wrote the metadata?

Dates:
Last modified: 08-Mar-2017
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: Susan A. Cochran
Geologist
2885 Mission Street
Santa Cruz, CA
United States of America

831-460-7545 (voice)
scochran@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/pacific_islands/oahu/portlock_1m_meta.faq.html>
Generated by mp version 2.9.49 on Fri Sep 13 15:01:12 2019