IKONOS Imagery for the Republic of Palau

The National Oceanic and Atmospheric Administration's (NOAA) National Ocean Service (NOS) is tasked with the coral mapping element of the U.S. Coral Reef Task Force (CRTF) under the authority of Executive Order 13089. NOS is responsible for coral reef mapping in Puerto Rico, the U.S. Virgin Islands, the Northwest Hawaiian Islands, the Main Eight Hawaiian Islands, and the U.S. Territories and Freely Associated States of the Pacific. Space Imaging, Inc (SI) and Analytical Laboratories of Hawaii, LLC (ALH) has produced GIS-compatible benthic habitat digital maps of the Republic of Palau using the classification scheme defined by NOAA. The map products produced through this project include baseline data of U.S. coral reefs, location of coral reef boundaries and overall coral reef cover, and the geomorphologic structure in and around coral reef systems. Maps include the 9 major and 23 detailed biological cover types, 4 major and 14 detailed geomorphological structure types, and 15 mutually exclusive zones specified in NOAA's hierarchical classification manual for coastal waters of the Republic of Palau. Benthic habitats are delineated from the coastline to water depths of 30 meters in GIS using manual interpretation techniques. NOAA utilizes IKONOS Multispectral (MSI) Satellite Imagery from Space Imaging, Inc., consisting of both newly acquired and archived imagery. The imagery consists of 1m panchromatic and 4m MSI with a horizontal accuracy of at least 5m CE95 at 1:4,800 National Map Accuracy Standard (NMAS). Once the imagery is processed, NOAA will use ALH's hand-digitize GIS approach to produce the benthic habitat maps at a minimum mapping unit of one acre, as well as NOAA's preferred random stratified accuracy assessment method.

Atmospheric correction removes atmospheric effects from the raw pansharpened data and retrieves surface reflectance, characterizing the surface properties, in order to improve the accuracy of image classification. Calibration coefficients for the satellite, provided by Space Imaging, were used to calculate at-satellite radiance, which was then transformed to reflectance.

618

This data is provided by Space Imaging for the U.S. Department of Commerce, the National Oceanic and Atmospheric Administration (NOAA), the National Ocean Service (NOS), the National Centers for Coastal Ocean Science (NCCOS), and the Center for Coastal Monitoring and Assessment (CCMA). The Government retains the exclusive rights to use, publish, and duplicate the original and derived products and data during the course of this contract. While every effort has been made to ensure the accuracy of the information supplied herein, Space Imaging does not guarentee the accuracy of geographic features or attributes. Space Imaging cannot be held responsible for any errors or omissions and reserves the right to change the content of its data, including the products and services described therein, at any time; therefore, all Space Imaging and third party information is provided "AS IS". Space Imaging DISCLAIMS ALL WARRANTIES WITH REGARD TO THE INFORMATION (INLCUDING ANY SOFTWARE) PROVIDED, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT. Space Imaging shall not be liable for any damages whatsoever, including any special, indirect, navigational, consequential, or incidental damages, or damages for lost profits, loss of revenue, or loss of use, arising out of access to, inablility to access, use or inability to use any Space Imaging mapping products or the information contained within them, whether such damages arise in contract, negligence, tort, under statute, in equity, at law, or otherwise.

None

None

None

None

none

none

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350

The IKONOS Imagery consist of 1m panchromatic and 4m MSI with a horizontal accuracy of at least 5m CE95 at 1:4,800 National Map Accuracy Standard (NMAS)

Atmospherically corrected data in units of remote-sensing reflectance were delivered in Unsigned Integer 16-bit (BIP) PIX format with an associated header file that includes the lat/long information for every pixel projected in UTM WGS-84 (Zone 53N).

All of the IKONOS imagery was purchased in National Imagery Transmission Format (NITF) with the associated Rational Polynomial Coefficients (RPCs or satellite ephemeris data). Raw satellite images were converted from Digital Numbers (DNs) to normalized reflectance. Normalized reflectance (or at-satellite reflectance) converts DNs into standardized, satellite-independent, comparable values. First developed for Landsat satellite imagery, the algorithm used to perform this conversion was modified for IKONOS image processing. As part of the conversion from DNs to at-satellite reflectance, the following equation is used (Green et al. 2000):R = pi * L/ (Eo cos(theta0) 1/r2)L = radiance (from calibration provided by Space Imaging). r = earth-sun distance in Astronomical Units. theta0 = the solar zenith angle Eo = the mean solar exo-atmospheric irradiance in each band. (A convolution of the spectral response and solar radiation from Neckel and Labs (1984) was used to get Eo.) The acquisition angles (ephemeris data) of the satellite relative to the ground at the time of image acquisition were also used. Calibration coefficients for the satellite, provided by Space Imaging, were used to calculate at-satellite radiance, which was then transformed to reflectance. The normalized reflectance imagery was then transformed into water reflectance (or the signal less than 10 cm above the water surface). Water reflectance uses the near-infrared band to remove radiance attributed to atmospheric and surface effects (Stumpf et al. 2003). Water reflectance estimates how the signal (photons) received by the satellite is diminished as it passes through the atmosphere on the way down to the water-atmosphere boundary and on the way back up to the satellite after the signal leaves the water-atmosphere boundary. Water reflectance also estimates how the signal at the satellite is diminished by water vapor, clouds, specular effects at the water surface (wave surface glint), and other signal- absorbing and diffusing materials.