Key Words: ocean GIS, ocean planning, ocean governance, ocean policy, shoreline, bathymetry

Abstract: GIS has traditionally been used for terrestrial applications. Some data sets are problematic when working in the ocean. Sorting through the available shorelines to find the "official" shoreline is an issue. The dynamic nature of the shoreline due to erosion and tidal range is difficult to capture in a GIS. Finding and combining multiple resolution survey data from various sources to create reliable bathymetric data usable on the PC is also a challenge. NOAA is working to create PC-based data sets and tools in ArcView that can be used for the Ocean Governance and Planning community. Key data sets for ocean planning are being created for the southeastern United States. A high-resolution shoreline will be created for this area by vectorizing the scanned byproducts of the original tide-controlled photography used for NOAA nautical charting. Bathymetric survey data will be combined to create bathymetric contours from the shoreline out to the Exclusive Economic Zone (EEZ), or 200-mile international boundary. These key data sets will be combined with other cadastral and natural resources data layers to create a GIS suitable for the ocean planning and governance community. Esri's ArcInfo will be used for data development with ArcView 3.0 as the final software that will serve the ocean planning community.

Introduction: Resources and uses of U.S. ocean areas are governed under a regime that is fragmented among federal and state authorities, based on jurisdictional boundaries and single-purpose statutes, and not integrated by one coherent set of national goals and guidance. The result is often inefficiency, jurisdictional confusion, and contentious decision making that often fails to address impacts on ocean resources. An important part of the comprehensive ocean planning process is the creation of a geographic information system (GIS). A GIS can be used as an aid to decision making, to identify conflict areas, and to assist in bringing together a broad user community interested in ocean resources.

Although resource managers and policy makers at all levels of government have called for changes in the U.S. ocean governance regime to redress these inefficiencies, it has been increasingly difficult to develop a comprehensive ocean resource strategy. In the absence of a national framework, the National Oceanic and Atmospheric Administration's (NOAA) Office of Ocean and Coastal Resource Management (OCRM) has encouraged states to consider developing comprehensive ocean policies and state and regional management plans. OCRM has teamed with the NOAA Coastal Services Center (CSC) and Strategic Environmental Assessment (SEA) Division to assist in this first regional ocean GIS effort. This paper outlines the process of designing and creating an ocean GIS, which serves as a unifying and non-contentious platform for regional ocean planning and policy dialogue in the southeastern U.S.

GIS has primarily been used for terrestrial-based applications. Finding supporting standards, data, and applications become problematic when working off shore. Because of difficulties with data acquisition, ocean data tend to be more sparse than their associated terrestrial-based data. For example, sorting through the available shorelines to identify an "official" shoreline is an issue. Finding and combining multiple resolution survey data from various sources to create reliable bathymetric data usable on the desktop is also a challenge. There is the critical issue of resolving the vertical datum when combing bathymetric and elevation data. In addition, the cadastral element of an ocean GIS quickly becomes a quagmire. Generally, the low-water line or baseline is used to calculate state and federal boundaries, where the mean high-water line is generally considered the shoreline.

Setting database priorities: In an effort to create a regional ocean GIS, state, federal, and regional partners worked through a process that outlined the priority issues and identified the data sets necessary for addressing these issues (See table 1). A high-resolution shoreline, bathymetry, and cadastral data layers were found to be fundamental to the broad spectrum of issues. In addition to the data sets required, a recent CSC survey revealed that the majority of the coastal community (including those in the Southeast) are using Environmental Systems Research Institute's (Esri) ArcView^® desktop mapping software. This project is committed to provide data that are structured to be readily used by those customers.

Shoreline: CSC has begun the process of collecting the key layers for inclusion in the ocean planning GIS. The high-resolution vector shoreline is being acquired from a combination of byproducts (T-sheets) of the NOAA nautical chart production process. The photography that was used to create the charts is the only universal, tide-controlled product that exists for the entire U.S. The most recent data (post 1990) have a digital CAD-like format that can be extracted and processed to produce a topologically structured vector shoreline. Pre-1990 products only exist in a raster scan of the photo separate from the chart. These raster scans are being vectorized using Esri's ArcScan^® using labor from the AmeriCorps National Civilian Community Corps. The final product will be a high-resolution shoreline (scales ranging from 1:5,000 to 1:20,000) for the Southeast with associated Federal Geographic Data Committee (FGDC)-compliant metadata.

Bathymetry: Creating a useable bathymetry data layer for a desktop mapping system requires discovering, inventorying, and combining multiple bathymetric sources and processing them into a simpler data structure that can be reasonably viewed by ArcView^®. A single clearinghouse does not exist for all bathymetric data. To create a regional bathymetric data set requires discovering and combining multiple sources of hydrographic survey, marine track-line, and research data. The NOAA National Geophysical Data Center (NGDC) is the largest archive of bathymetric data, with U.S. Geological Survey (USGS), the U.S. Army Corps of Engineers, and the individual states providing a small amount of supplemental data. These data range greatly in accuracy, date, and density. Any areas that have been recently surveyed, including major harbors and some parts of the Exclusive Economic Zone (EEZ), have highly accurate and dense coverage. Estuarine and near-shore areas, as well as those with few navigational hazards (i.e., deep-water areas) have older and sparser data. Because very little attention has been paid to the off-shore areas by FGDC and commercial vendors, non-navigational related standards and procedures for bathymetry are either not well documented or do not exist. CSC has begun inventorying available data and developing a methodology for combining these data, and will provide a complete bathymetric data layer for use by the southeastern ocean planning community.

Boundary: A cadastral data layer is just as necessary in mapping the ocean realm as it is on the land. Ocean boundaries and the rights associated with ownership have become even more critical to define as the ocean resources increase in value. Because ocean survey markers are virtually non-existent, it becomes even more important that all parties understand the boundaries of features of state, federal, and international interest. The baseline is a line of reference that is used to calculate the outer limits of the state and federal waters (i.e., Territorial sea, Contiguous Zone, EEZ). Generally, the low-water line is used, but deciding on this line can be an item of contention. Because the baseline is used to project a boundary of 3 miles, 9 miles, 12 miles, or 200 miles, a small shift in the baseline can shift the ownership boundary and result in large amounts of lost revenue. The U.S. Department of the Interior, Minerals Management Service, in conjunction with NOAA, the individual states, and the U.S. Department of State Ad Hoc Interagency Baseline Committee, work to resolve and map the baseline. In the Southeast, only South Carolina has a resolved baseline. In the process of mapping ocean boundaries, this project will gather the best available information for the baseline. Hopefully, in the process, a dialogue between the responsible agencies will be stimulated that will help to resolve the boundary issue.

Building an ocean planning GIS provides an excellent opportunity to build partnerships between the federal and state sectors in support of ocean resource management. In addition, this project aids in leveraging and coordinating institutional resources and applying them to specific coastal issues, such as habitat protection and coastal hazards, as well as ocean planning and governance.

Cindy Fowler
National Oceanic and Atmospheric Administration
Coastal Services Center
2234 South Hobson Ave.
Charleston, SC 29405-2413
Ph: (803) 974-6249
FAX: (803) 974-6315
cfowler@csc.noaa.gov

Joelle Gore
National Oceanic and Atmospheric Administration
Office of Ocean and Coastal Resource Management
1305 East-West Highway, SSMC4, 11^th Floor
Silver Spring, MD 20910
Ph: (301) 713-3117 x177
FAX: (301) 713-4367
jgore@coasts.nos.noaa.gov