Contours--Offshore Pigeon Point, California

This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore Pigeon Point map area, California. The vector data file is included in "Contours_OffshorePigeonPoint.zip", which is accessible from http://dx.doi.org/10.5066/F7513W80
10-m interval contours of the Offshore Pigeon Point map area, California, were generated from bathymetry data collected by the U.S. Geological Survey (USGS) and by California State University, Monterey Bay (CSUMB). Mapping was completed between 2006 and 2009 using a combination of a 244-kHz Reson 8101 multibeam echosounder and a 234-kHz SEA SWATHplus bathymetric sidescan-sonar system. The mapping missions 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.

DS 781的本章节提供了加利福尼亚州鸽子角近海（Offshore Pigeon Point）海域多张海底地形图的水深等值线数据。矢量数据文件包含于"Contours_OffshorePigeonPoint.zip"中，可通过http://dx.doi.org/10.5066/F7513W80获取。
加利福尼亚州鸽子角近海海域的10米间隔等值线，由美国地质调查局（U.S. Geological Survey, USGS）与加州州立大学蒙特雷湾分校（California State University, Monterey Bay, CSUMB）采集的水深数据生成。测绘工作于2006至2009年间完成，采用244kHz Reson 8101多波束测深仪与234kHz SEA SWATHplus水深侧扫声呐系统的组合方案。本次测绘任务采集了约10米等深线至加州州域3海里界线以外区域的水深数据。
10米间隔的水深等值线基于经过修正的2米分辨率水深表面生成。原始表面通过ArcGIS中的焦点均值（Focal Mean）工具，采用半径20至30米的圆形邻域（依区域而定）进行平滑处理。随后使用ArcGIS空间分析（Spatial Analyst）模块的等值线工具，从该平滑后的表面生成等值线。最终输出保留了连续性最佳的等值线段，剔除了较短的线段与孤立的岛屿多边形。最后将等值线裁剪至测绘区域的边界范围内。