Benthic Habitats of Palau Derived From IKONOS Imagery, 2003-2006

This project is a cooperative effort among the National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal Monitoring and Assessment; the University of Hawaii; and Analytical Laboratories of Hawaii, LLC. The goal of the work was to map the coral reef habitats of Palau by visual interpretation and manual delineation of IKONOS satellite imagery. A two tiered habitat classification system was used in this work. The scheme integrates geomorphologic reef structure and biological cover into a single scheme and subsets each into detail. It also includes thirteen zones.

The National Ocean Service is conducting a map production effort 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.

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The National Oceanic and Atmospheric Administration (NOAA) National Centers for Coastal Ocean Science (NCCOS) produced this data CD-ROM. 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.

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Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 1; ESRI ArcCatalog 9.0.0.535

This interim GIS polygon product was generated from eleven regions of Palau which, when combined, constitute the entire Palau Archipelago. A statistical analysis that generates a Tau statistic will be performed. The Tau statistic for the major classes exceeded 0.85 and exceeded 0.75 for detailed classes. Overall thematic accuracy exceeded 85% for major classes and 75% for detailed classes.

RMS from digitized output was determined using the ESRI RMEer2 extension and shown to be less than 1m when conducted at 1:6000 scale.

NOAA supplied georeferenced imagery to Analytical Laboratories of Hawaii. Delineation of all habitat boundaries was conducted with the image scale at 1:6,000 or less. The minimum mapping unit (MMU) for identifying habitats or features was 1 acre. The software utilized in this project was designed to alert the photo interpreter each time a polygon was drawn smaller than the MMU. When this occurred the photo interpreter has the choice whether to include the polygon in the data set. Only in areas where local coral reef managers expressed interest in specific map classes or in Marine Protected Areas or for areas of land were polygons of smaller then the MMU allowed. Furthermore, land features were delineated with the MMU restriction removed.

All mapping was conducted from orthorectified IKONOS satellite imagery provided by NOAA prior to map production. IKONOS satellite imagery was corrected for atmospheric and water column effects, color balanced, pan sharpened and deglinted. 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.GIS topologic quality was established by executing ArcView extension routines that check for: overlapping polygons, multipart polygons, sliver polygons, void polygons and zone attribute check. 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.