This polyline shapefile depicts bathymetric contour line coverage for California that generally covers the continental shelf at 50 foot contour resolution. The contours were developed by interpolating National Ocean Service (NOS) Hydrographic Survey depth points. The TopoGrid algorithm within ArcInfo software was the primary gridding interpolation procedure, followed by a standard contouring routine. The contours are one possible interpretation based on chosen contouring procedures. The purpose of this contour map is to visualize changes in ocean depths relative to sea level in the nearshore California continental shelf, which is the portion of the continent beneath the ocean’s surface. The bathymetric measurements used here refer to the study of water depths only and do not include the underwater, or submarine, topography of the ocean floor except as it relates to water depths. These data are not suitable for navigation purposes. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.