This project is a cooperative effort between 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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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 percent for major classes and 75 percent for detailed classes.
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.
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.
RMS from digitized output was determined using the ESRI RMEer2 extension and shown to be less than 1m when conducted at 1:6000 scale.
This document identified the zone, structure and biological cover types attributed in the data set
This ArcView extension was used to digitize and attribute benthic zones, structure and biological cover of this map.
Used to identify and digitize benthic habitats for Palau.
Benthic habitat maps were digitized by delineating habitat boundaries from georeferenced orthorectified IKONOS satellite imagery loaded into ArcView 3.3 GIS software with the Image Analysis and NOAA Coral Reef Habitat Digitizing extensions both activated. Digitizing was conducted using heads-up on computer screen methods with the minimum mapping unit (MMU) set to 1 acre and the image scale at 1:6,000 or less. All IKONOS imagery was processed by NOAA prior to map production. The imagery was corrected for atmospheric and water column effects, pan sharpened and deglinted. During the digitizing process, images were stretched and contrast, brightness and color balance were modified using the Arc View Image Analysis Extension to enhance features in the processed imagery. The overall map production plan includes a first draft map completed with features in the imagery where uncertainties existed, due to confusing or difficult to interpret signatures, identified for future ground validation effort. An ArcView GIS point theme was generated with points positioned on the features of uncertain habitat type or along transects though gradients between habitat types. The GIS points are converted to GPS waypoints using Trimble Pathfinder Software and are navigated to in the field using a Trimble GeoExplorer 3 GPS data logger. A benthic habitat characterization is conducted at each site by use of a tethered video camera snorkeling, free diving, or where water depth and clarity permitted, by observation from the surface. GPS data were collected at each location and site ID, depth, habitat type, zone and the method used to make the assessment are recorded. A second draft of the map is generated incorporating these ground validation data. This is a draft 1 map product. Though the product is topologically clean and meets NOAA GIS standards, attribute accuracy is at an interim level of production and will be considerably modified prior to draft 2 and final publication.
Feature geometry.
ESRI
4 digit numerical value representing a unique habitat combination of structure and cover attributes
Habitat digitizing extension
Incremental value generated for QA/QC adjacency test
ArcView script
Area of polygon
Perimeter of polygon
Area of polygon in acres
Number of region
Manually assigned string
Major reef structure
Detailed structure
Major biological cover
Habitat classification scheme
Percent biological cover of major cover type
Geomorphologic zone
Concatenated field of major cover and percent cover used for legend fill
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. NOAA makes no warranty regarding these data, expressed or implied, nor does the fact of distribution constitute such a warranty. NOAA and NODC cannot assume liability for any damages caused by any errors or omissions in these data, nor as a result of the failure of these data to function on a particular system.
Contact NOAA for distribution options (see Distributor).
