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, Analytical Laboratories of Hawaii, LLC. The goal of the work was to incorporate previously developed mapping methods to produce benthic habitat maps generated by photo interpreting georeferenced IKONOS satellite imagery. These point data were generated to conduct ground validation during map preparation.
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 purpose of this survey was to investigate areas of imagery where uncertainties exist on the photo interpreter's behalf during the decision making process of benthic habitat type for Palau.
ground condition
Not for navigation
1305 East West Highway
The points in this thematic data layer were acquired by GPS data using a Trimble GeoExplorer 3 with a customized data dictionary designed to reflect the NOAA Classification Scheme for Benthic Habitats of the Pacific 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. Attributes are all expected to be correct.
The sites for ground validation were selected to specifically investigate habitat types and gradients of spectral signatures. All areas where uncertainty existed on the part of the photo interpreter during habitat delineation were investigated in the field. Waypoints in these areas were generated on the georeferenced imagery. The waypoints were navigated to and occupied. The habitat was observed and GPS data collected. One hundred GPS positions were collected at one-second intervals for each survey site. The positions were averaged to obtain a single survey point. The data were post processed for differential correction. The general area was explored and, as needed, additional GPS positions were collected to mark transitions between habitat types of areas mapped at the level of the minimum mapping unit (MMU). These data are believed to be consistent.
1140 field positions were occupied and habitat characterization conducted for ground validation during this work. These data were included in the dataset as a GIS layer and the first draft map was edited based on this ground truth. All areas where uncertainty existed on the part of the photo interpreter during habitat delineation were investigated in the field. All data were collected and integrated into the mapped products as planned.
Point accuracy was determined by three tests producing circular RMS statistic. Point GPS data were acquired by repeated occupation of a fixed point yielding a 95 percent sigma RMS of 5 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 ground validation data are at least 95 percent sigma of 5 meters.
The first draft of each benthic habitat map was generated by visual interpretation of the habitat boundaries from remote sensing imagery, and areas where habitat determination was uncertain were identified. Waypoints in these areas were generated on the geo-referenced imagery and over laid on the draft maps in the GIS. The areas were printed and water proofed in preparation for taking them into the field. The waypoints were navigated to and occupied using the appropriate size boats. The habitat was observed and GPS data collected. One hundred GPS positions were collected at one-second intervals for each survey site. The positions were averaged to obtain a single survey point. The data were post processed for differential correction to the nearest CORS. The general area was explored and, as needed, additional GPS positions were collected to mark transitions between habitat types of areas mapped at the level of the minimum mapping unit (MMU). The field ground validation data were overlaid on the imagery with the first draft habitat map in the GIS. The habitat polygons were edited to resolve uncertainties. These ground validation point data are provided in this thematic GIS shape file.
1320 Aalapapa Dr.
Metadata imported.
Internal feature number.
ESRI
Feature geometry.
UTM Zone
User Defined
Name of island where data was collected
User defined
Abbreviation for Accuracy Assessment data type
Unique site ID
Water Depth in feet
GPS Data Logger
Major reef structure type
Habitat classification scheme for the Pacific
Habitat at GPS point position
GPS data logger
Detailed reef structure type
Habitat classification scheme of the Pacific
Primary biological cover type
Percent of biological cover in survey area
Geomorphologic zone
Method used for field observations
Vertical relief of survey area; relative scale of 1 (lowest relief) to 5 (highest relief
Percent live coral cover observed during field survey
Percent macroalgal cover observed during field survey
GOS data logger
Percent sea grass cover observed during field survey
Percent turf cover observed during field survey
Percent sand cover observed during field survey
Percent mud cover observed during field survey
Habitat notes
Percent of substrate bare of occupied by other biological cover observed during field survey
Underwater photo record
Measure of positional strength of GPS satellite configuration
Date of GPS data collection
Time of GPS data collection
Precision of horizontal position
Position precision
Geographic position
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.
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