Twenty-one distinct benthic habitat types within eight zones were mapped directly into a GIS system using visual interpretation of orthorectified aerial photographs. Benthic features were mapped that covered an area of 1600 km^2. In all, 49 km^2 of unconsolidated sediment, 721 km^2 of submerged vegetation, 73 km^2 of mangroves, and 756 km^2 of coral reef and colonized hardbottom were mapped.
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| Range of values | |
|---|---|
| Minimum: | 59 |
| Maximum: | 385380804 |
| Value | Definition |
|---|---|
| 11 | Unconsolidated Sediments/Sand |
| 12 | Unconsolidated Sediments/Mud |
| 31 | Coral Reef and Hardbottom/Colonized Hardbottom/Linear Reef |
| 32 | Coral Reef and Hardbottom/Colonized Hardbottom/Spur and Groove |
| 33 | Coral Reef and Hardbottom/Colonized Hardbottom/Individual Patch Reef |
| 34 | Coral Reef and Hardbottom/Colonized Hardbottom/Aggregated Patch Reef |
| 35 | Coral Reef and Hardbottom/Colonized Hardbottom/Scattered Coral/Rock in Unconsolidated Sediment |
| 36 | Coral Reef and Hardbottom/Colonized Hardbottom/Colonized Pavement |
| 37 | Coral Reef and Hardbottom/Colonized Hardbottom/Colonized Bedrock |
| 38 | Coral Reef and Hardbottom/Colonized Hardbottom/Colonized Pavement with Sand Channels |
| 41 | Coral Reef and Hardbottom/Uncolonized Hardbottom/Reef Rubble |
| 43 | Coral Reef and Hardbottom/Uncolonized Hardbottom/Uncolonized Pavement |
| 44 | Coral Reef and Hardbottom/Uncolonized Hardbottom/Uncolonized Bedrock |
| 51 | Other Delineations/Land |
| 52 | Other Delineations/Mangrove |
| 53 | Other Delineations/Artificial |
| 55 | Other Delineations/Unknown |
| 211 | Submerged Vegetation/Seagrass/Continuous Seagrass/90-less than 100% |
| 2121 | Submerged Vegetation/Seagrass/Patchy/70- less than 90% |
| 2122 | Submerged Vegetation/Seagrass/Patchy/50- less than 70% |
| 2123 | Submerged Vegetation/Seagrass/Patchy/30- less than 50% |
| 2124 | Submerged Vegetation/Seagrass/Patchy/10- less than 30% |
| 2221 | Submerged Vegetation/Macroalgae/Patchy/50- less than 90% |
| 2222 | Submerged Vegetation/Macroalgae/Patchy/10- less than 50% |
Puerto Rico Department of Natural and Environmental Resources, University of Puerto Rico, the United States Geological Survey, the National Park Service, Virgin Islands Department of Planning and Natural Resources: Fish and Wildlife Division, University of Virgin Islands, Cons. Data Center, The Nature Conservancy, SeaGrant, and other local and regional experts for input and review.
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.
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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. Additional collateral information including previously completed habitat maps, NOS nautical charts, and other descriptive references dealing with benthic and coastal habitats of Puerto Rico and the U.S. Virgin Islands was used to assist with image interpretation.
A first draft map was completed and features in the imagery where uncertainties existed, due to confusing or difficult to interpret signatures, were 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 were converted to GPS waypoints using Trimble Pathfinder Software and were navigated to in the field using a Trimble GeoExplorer 3 GPS data logger.
A benthic habitat characterization was conducted at each site by snorkeling, free diving, or via observations from the surface where water depth and clarity permitted. GPS data were collected at each location and site ID, depth, habitat type, zone and the method used to make the assessment were recorded. The ground validation data were incorporated into the second draft of each map.
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The two test sites chosen were located at Buck Island National Monument, St. Croix, and La Parguera, Puerto Rico. A stratified sampling protocol was used during which sample sites were pre-selected so that overall thematic accuracy of the three major habitat types across the range of depths and water conditions found in the field could be evaluated. Each preselected site was navigated to using a real time Differential Global Positioning System (DGPS) and habitat data was acquired.
The Buck Island accuracy assessments tests showed that the ability to generate benthic habitat maps with an overall accuracy of 93.6 percent (Kappa 0.90) for on-screen digitizing and 87.8 percent (Kappa 0.82) for maps digitized directly from stereo pairs. Overall accuracy in the Parguera area was determined to be 93.6 percent (Kappa 0.93).
The Minimum Mapping Unit (MMU) for identifying habitats or features was 1 acre for visual photointerpretation. The software utilized in this project was designed to alert the photointerpreter each time a polygon was drawn smaller than the MMU. When this occurred the photointerpreter has the choice of whether to include the polygon in the data set or not.
GIS topologic quality was established by executing ArcView extension routines that check for: overlapping polygons, multipart polygons, sliver polygons and void polygons. 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.
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- Access_Constraints: None
- Use_Constraints: Not for navigation
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. Disclaimer- While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
| Data format: | |
|---|---|
| Network links: |
https://cdn.coastalscience.noaa.gov/datasets/e95/data/map_pdfs/StCroix_map.zip |