Oahu Accuracy Assessment Point Data for Benthic Habitats of the Main Hawaiian Islands Prepared by Visual Interpretation from Remote Sensing Imagery Collected by NOAA Year 2000

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 develop coral reef mapping methods and compare benthic habitat maps generated by photointerpreting georeferenced color aerial photography, hyperspectral and IKONOS satellite imagery. The cost effectiveness of acquisition and processing of remotely sensed imagery varies significantly between types of platforms deployed and imaging systems used to acquire the data. As a result, it is important to identify the strengths and weaknesses of the map products prepared from each of the types of digital imagery. These Accuracy Assessment point data were generated to assess the accuracy of the individual maps created from the three types of source information.Testing showed that the ability to generate benthic habitat maps with an overall accuracy of 90% to 95% confidence interval is reaching a threshold using imagery with three meter pixel size allowing for spectral enhancement of the imagery with reduced resolution. Increasing the intensity of field observation can partially compensate for this decrease in accuracy of the maps generated from the largest pixels. Habitat maps prepared from IKONOS satellite imagery should be accompanied by field observation wherever possible.

The National Ocean Service is conducting research 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. The goal of the work was to develop coral reef mapping methods and compare benthic habitat maps generated by photointerpreting georeferenced color aerial photography, hyperspectral and IKONOS satellite imagery. These Accuracy Assessment point data were generated to assess the accuracy of the individual maps created from the three types of source information.

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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 2000 Version 5.0 (Build 2195) Service Pack 3; ESRI ArcCatalog 8.2.0.700

The points in this thematic data were acquired by GPS using a Trimble GeoExplorer 3 with a customized data dictionary designed to reflect the NOAA Classification Scheme for Benthic Habitats of the Main Eight Hawaiian Islands. All habitat determinations were made in the field, recorded in the GPS data logger and seamlessly transferred to ArcView GIS using Trimble Path Finder Office Software.

Point accuracy was determined by three tests producing circular RMS statistic. Point GPS data were acquired by repeated occupation a fixed point yielding a 95% sigma RMS of 2 meters compared to the position mean. Replicate GPS positions were collected after navigating to a way point by boat yielding RMS value of 5 meters. Registered monuments were occupied and replicate positions collected yielding an RMS value of 3 meters. Thus, all point features in these accuracy assessment data are at least 95% sigma of 5 meters.

Data are complete. Habitat attributes are determined by direct observation in the field. These data are considered truth at the time of collection. Habitat types are subject to change over time due to population dynamics of the dominant biological communities.

To maintain objectivity in the analysis of accuracy, an independent team conducted the field assessments. The Coral Reef Assessment and Monitoring Program (CRAMP) team made all benthic habitat decisions independent of the Analytical Laboratories of Hawaii (ALH) contractor. Furthermore, the CRAMP team independently conducted the assessment of the extent to which the photointerpretation met the field assessment determinations. These data were then used to prepare the statistical contrasts of the accuracy of the maps for each of the test areas for each of the image types.Transfer of the habitat assessment data is seamless from the field determination to the final GIS product. The data is not transcribed or rewritten by hand. Errors in processing are not expected.