Data Management Plan (Deprecated)

NOAA is responsible for depicting on its nautical charts the limits of the 12 nautical mile Territorial Sea, 24 nautical mile Contiguous Zone, and 200 nautical mile Exclusive Economic Zone (EEZ). The outer limit of each of these zones is measured from the U.S. normal baseline, which coincides with the low water line depicted on NOAA charts and includes closing lines across the entrances of legal bays and rivers, consistent with international law. The U.S. baseline and associated maritime limits are reviewed and approved through the interagency U.S. Baseline Committee, which is chaired by the U.S. Department of State. The Committee serves the function of gaining interagency consensus on the proper location of the baseline using the provisions of the 1958 Convention on the Territorial Sea and the Contiguous Zone, to ensure that the seaward extent of U.S. maritime zones do not exceed the breadth that is permitted by international law. In 2002 and in response to mounting requests for digital maritime zones, NOAA launched a project to re-evaluate the U.S. baseline in partnership with other federal agencies via the U.S. Baseline Committee. The focus of the baseline evaluation was NOAA's largest scale, most recent edition nautical charts as well as supplemental source materials for verification of certain charted features. This dataset is a result of the 2002-present initiative and reflects a multi-year iterative project whereby the baseline and associated maritime limits were re-evaluated on a state or regional basis. In addition to the U.S. maritime limits, the U.S. maritime boundaries with opposite or adjacent countries as well as the US/Canada International Boundary (on land and through the Great Lakes) are also included in this dataset.

Process Steps:

• 2011-03-01 00:00:00 - From 2002 to 2010, the interagency U.S. Baseline Committee re-evaluated the U.S. baseline and associated maritime limits as depicted on NOAA charts on a state or regional basis. As a result of this multiple year, iterative project, digital state/regional maritime limits, including the 200nm EEZ, were produced and published in ESRI Shapefile format on NOAA\x92s Office of Coast Survey website. To create a seamless, continuous maritime limits dataset, OCS did the following: 1) transformed the state/regional digital limits, in SHP format, from NAD83 to WGS84; 2) merged the WGS84 SHP files into a single dataset using ESRI ArcGIS and imported into a file geodatabase; 3) segmented the merged limits according to chart symbology groupings as well as feature type (e.g. maritime boundary, maritime limit, or land boundary) to more closely match NOAA charts; and 4) re-attributed the dataset | Source Produced: Merged Digital Maritime Limits and Maritime Boundaries (Citation: Regional Digital Maritime Limits and Maritime Boundaries)
• 2011-03-01 00:00:00 - The coordinates of US/Canada international boundary were obtained from International Boundary Commission in NAD83 and saved into a text file. A point shapefile was created based on the text file in NAD83 and then transformed to WGS84. Polylines were constructed using the point shapefile. All polylines were constructed as rhumb lines, except the following three portions: 1) line segment from 43.631127N, 76.796687W to 43.631127N, 78.690388W; 2) line segment from 41.676561N, 82.397473W to 41.676561N, 82.679716W; 3) line segment in Gulf of Maine ruled by ICJ. These three portions were constructed as geodesic lines. The polylines were segmented according to the grouping of published coordinates on IBC website. New attributes were created and the polyline was attributed. | Source Produced: US/Canada international Boundary (Citation: Geographical Positions along the International Boundary (NAD83))
• 2010-01-01 00:00:00 - US/Canada international boundaries generated in the second process step were imported into file geodatabase and merged with maritime limits generated in the first process step. Topology rules were established in the file geodatabase to detect overlapping, self-intersecting, and dangling polyline features. Any topological errors flagged by topology check were investigated and corrected when necessary. When a polyline feature spans across -/+180 longitude, ESRI clips the feature at the longitude, resulting in dangling polyline. Topology errors as a result of clipping at 180 longitude were marked as exception. Other topology errors were corrected. The dataset was exported as a shapefile. | Source Produced: US Baseline Committee Approved Maritime Limits and Boundaries (Citation: Merged Digital Maritime Limits and Maritime Boundaries)
• 2013-01-01 00:00:00 - Maritime limits and boundaries are updated using the most recent edition, largest scale nautical charts. Updates are triggered by a new chart edition, or by a formal request to re-evaluate the baseline. Charts are used as a backdrop in the ESRI ArcMap environment to create vector shorelines and lines closing the entrances to legal bays, rivers, and harbors. These lines are imported to the Caris LOTS environment. The "Enevelope of Arcs from normal baselines" tool is applied to vector shorelines, and the "Envelope of Arcs from straight baselines" tool is applied to closing lines. As input to the tools, OCS selects the limit distance in nautical miles and designates minimum attributes for the baseline points. The tool generates the contributing baseline points and the boundary limit using a wagon-wheel filtering process of rolling a circle with a diameter specified by the limit distance and choosing the seaward-most points along the low water line. Previously approved limits are manually intersected and replaced with the revised limits to create seamless, revised limit lines. Caris generated EOA control lines, which display how baseline points contribute to particular arc segments of the limit line, are used to inform the manual intersect and replace function. The final dataset is exported from Caris to a shapefile in WGS84, and attributed in the ESRI ArcMap environment. (Citation: US Baseline Committee Approved Maritime Limits and Boundaries)