U.S. Virgin Islands and British Virgin Islands ESI: INDEX

This data set comprises the Environmental Sensitivity Index (ESI) data for the Virgin Islands. ESI data characterize estuarine environments and wildlife by their sensitivity to spilled oil. The ESI data include information for three main components: shoreline habitats, sensitive biological resources, and human-use resources. This data set contains data for the study area Index.

The ESI data were collected, mapped, and digitized to provide environmental data for oil spill planning and response. The Clean Water Act with amendments by the Oil Pollution Act of 1990 requires response plans for immediate and effective protection of sensitive resources.

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Prepared by Research Planning, Inc., Columbia, South Carolina for the National Oceanic and Atmospheric Administration (NOAA), National Ocean Service, Office of Response and Restoration, Hazardous Materials Response Division, Seattle, Washington; United States Environmental Protection Agency; United States Coast Guard; U.S. Virgin Islands Department of Planning and Natural Resources; British Virgin Islands Conservation and Fisheries Department; and United States Department of the Interior.

Resource Description - ESI Atlas for Virgin Islands

Although these data have been processed successfully on a computer system at the National Oceanic and Atmospheric Administration, no warranty, expressed or implied, is made by NOAA regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. NOAA warrants the delivery of this product in computer-readable format, and will offer a replacement copy of the product when the product is determined unreadable by computer input peripherals, or when the physical medium is delivered in damaged condition.

Contact NOAA for distribution options (see Distribution_Information).;

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DO NOT USE MAPS FOR NAVIGATIONAL PURPOSES. Besides the above warning, there are no use constraints on these data. Acknowledgment of the publishers and contributing sources listed in Data_Set_Credit (below) would be appreciated in products derived from these data.

The software packages used to develop the atlas are Environmental Systems Research Institute's ARC/INFO(r) (version 8.0.2) and ORACLE(r) RDBMS (version 8.0.5.0.0). The hardware configuration is Hewlett Packard workstations (models 715/50 and 712/80i with 4 X-terminals) with UNIX operating system (HP-UX Release A.10.20). The following files are included in the data set: benthic.e00, birds.e00, bio_lut.e00, biofile.e00, biores.e00, breed.e00, breed_dt.e00, esi.e00, fish.e00, fishl.e00, habitats.e00, hydro.e00, index.e00, invert.e00, invertl.e00, mgt.e00, m_mammal.e00, reptiles.e00, seasonal.e00, shelfbnd.e00, soc_dat.e00, soc_lut.e00, socecon.e00, sources.e00, species.e00, status.e00, t_mammal.e00, wetlands.e00.

The attribute accuracy is estimated to be "good" given the years of ESI experience, the data input methodology, the quality control review sessions, and the digital logical consistency checks.

The ESI data use USGS 1:24,000 topographic quadrangles as the basemap. It is estimated that the ESI shoreline classification has a minimum mapping unit of 50 feet.

The intertidal shoreline habitats of the U.S. Virgin Islands were previously mapped during overflights and ground surveys conducted for the Virgin Islands Resource Management Cooperative and the National Oceanic and Atmospheric Administration (NOAA), published in 1986. For the current project, the original ESI maps were re-examined and fully updated using the sources and methods described below. As a first step, vertical aerial photographs were examined at the offices of the USVI Department of Planning and Natural Resources (DPNR) in St. Thomas and the offices of the BVI Conservation and Fisheries Department (CFD) on Tortola. The initial aerial photograph classification was followed by overflight surveys of the entire study area, flying at elevations of 400-600 feet and slow air speed. Overflights were conducted using U.S. Coast Guard (USCG) helicopters, pilots, and support crew. During this work, an experienced coastal geologist delineated the intertidal shoreline habitats directly onto 1:24,000-scale USGS or 1:25,000-scale UKDOS topographic maps. Where appropriate, multiple habitats were described for each shoreline segment. Data from the National Wetlands Inventory (NWI) for the USVI, published in draft form in 1989 (based on 1:40,000 1983 CIR and 1985 B-W photography), was also used as a supplementary data source, particularly for mangrove areas and tidal flats. In many cases, the depiction of mangroves was modified substantially from the original NWI data, based on the more recent aerial photography and overflights, as well as information provided by expert reviewers. Mangrove polygons for the BVIs were based primarily on digital data from the 1993 Coastal Resource Atlas of the British Virgin Islands produced by the Natural Resources Institute (NRI), Overseas Development Administration (source scale 1:10,000). Mangrove polygons from the NRI data set were generally not altered, although in some cases mangrove areas identified during the overflights and by expert reviewers may have been added or changed slightly.

The digitization of shoreline types, biological resources, and human-use resources is a complex and highly quality-controlled process. Existing digital shoreline data are integrated into a study-wide basemap. In order to facilitate digitizing, the entire study area is split into individual quadrangles using the INDEX data layer. The first layer of information digitized is the ESI shoreline classification. The ESI habitat ranking is compiled onto 1:24,000 USGS topographic quadrangles by a geomorphologist. The hardcopy maps are then digitized and checked using both on-screen and hardcopy reviews. The edited maps are updated and checked once again for completeness and topological and logical consistency. Any errors in the shoreline classification are updated prior to digitization of the biological and human-use layers. All layers use the shoreline as the geographic reference so that there are no slivers in the geographic coordinates. The hardcopy biological information is compiled onto 1:24,000 USGS topographic quadrangles by a biological expert using data from regional specialists in the form of maps, tables, charts, written descriptions of wildlife distributions, and personal interviews. Concurrently, digital data sources are imported, projected, checked for quality control, and integrated into the data structure. The hardcopy data are digitized, checked using both digital and on-screen procedures, integrated with existing data, plotted, and sent out for review by the regional specialists. The edited maps are updated, checked once again, and the final product plotted (at approximately 1:55,000 scale). A team of specialists reviews the entire series of maps, checks all data, and makes final edits. The data are then merged to form the study-wide layers. The data merging includes a final quality control check where labels, chains, and polygons are checked for attribute accuracy. To finalize the data checking process, each data layer is checked using a standardized form by two GIS personnel (a technician and the GIS manager), and each attribute database is checked using several programs that test the files for missing or duplicate data, rules for proper coding, GIS topological consistencies (such as dangles, unnecessary nodes, etc.), and ORACLE(r) to ARC/INFO(r) consistencies. A final review is made by the GIS manager, where the data are written to CD-ROM and the metadata are written. ESI data are processed into multiple formats to make them useful to a wider community of GIS/mapping users. Distribution formats include ARC export, MOSS and Shape files, and MARPLOT map folders. An ArcView ESI project and ESI_Viewer product are also included on the CDs for ease of use of the ESI data. The database files are distributed both in the NOAA standard relational database format (see NOAA Technical Memorandum NOS ORCA 115) and in a simplified desktop flat file format. This metadata document includes information on both of these database formats. The section Spatial_Data_Organization_Information refers to the source files in ARC export format only.