Contours--Offshore Santa Cruz, California

This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore Santa Cruz map area, California. The vector data file is included in "Contours_OffshoreSantaCruz.zip", which is accessible from http://dx.doi.org/10.5066/F7TM785G.
10-m interval contours of the Offshore Santa Cruz map area, California, were generated from bathymetry data collected by the U.S. Geological Survey (USGS). Mapping was completed in 2009 using a 234-kHz SWATHplus bathymetric sidescan-sonar system. The mapping mission collected bathymetry data from about the 10-m isobath to beyond the 3-nautical-mile limit of California’s State Waters.
Bathymetric contours at 10-m intervals were generated from a modified 2-m bathymetric surface. The original surface was smoothed using the Focal Mean tool in ArcGIS and a circular neighborhood with a radius of 20 to 30 meters (depending on the area). The contours were generated from this smoothed surface using the ArcGIS Spatial Analyst Contour tool. The most continuous contour segments were preserved while smaller segments and isolated island polygons were excluded from the final output. The contours were then clipped to the boundary of the map area.