One-minute grid covering the South Atlantic Bight. Each grid cell is one-minute latitude by one-minute longitude. The grid (actually a polygon shapefile) extends from the VA/NC border south along the US east coast, around the southern tip od FL and westward through the Dry Tortugas. The grid extends from the shoreline to approximately five nautical miles beyond the 200 m depth contour (roughly the continental shelf break). Each grid cell is identified by an eight digit "block" number representing the latitude and longitude (in degrees and minutes) of the southeast corner of the grid cell. Each grid cell is coded to a bottom type based on the SEAMAP Bottom Mappping data that fall within the cell. Where a data point or line falls precisely on the border between two grid cells, the datum is assigned to the north or west cell. Certain line (transect) data assign bottom values to the grid cell in which the line begins. Otherwise, line data code each grid cell crossed. Polygon data assigns bottom value to each grid cell that a given polygon covers. Each grid cell is attributed to reflect the number and type of bottom data that fall within the cell. Each grid cell within the one-minute grid was coded to a bottom type of either
Hard Bottom (HB),
Possible Hard Bottom (PH), or
Not Hard Bottom (NH) ,
based on the SEAMAP Bottom Mapping point, line, and polygon data that intersect the grid cell. If a cell has any HB data in it, it is coded to HB regardless of any NH data in the cell. If a cell has NH and no other type of data, it is coded to NH. If a cell has no data, it is not coded.
See the following documents for more detail:
Moser, M.L., S.W. Ross, S.W. Snyder, and R.C. Dentzman. 1995. Distribution of Bottom Habitats on the Continental Shelf off North Carolina. Final Report to Marine Resources Institute, South Carolina Department of Natural Resources for the Southeast Area Monitoring and Assessment Program, Bottom Mapping Work Group. 81p.
Perkins, T.H., H.A. Norris, D.T. Wilder, S.D. Kaiser, D.K. Camp, R.E. Matheson, Jr., F.J. Sargent, M.M. Colby, W.G. Lyons, R.G. Gilmore, J.K. Reed, G.A. Zarillo, K. Connell, and M. Fillingfin. 1997. Distribution of Hard-Bottom Habitats on the Continental Shelf off the Northern and Central East Coast of Florida. Final Report submitted to the Southeast Area Monitoring and Assessment Program Bottom Mapping Workgroup and the National Marine Fisheries Service. vii + 55p, 1 appendix.
Van Dolah, R.F., P.P. Maier, G.R. Sedberry, and C.A. Barans. 1994. Distribution of Bottom Habitats on the Continental Shelf of South Carolina and Georgia. Final Report submitted to the Southeast Area Monitoring and Assessment Program, South Atlantic Committee. 46 p.