Contours--Offshore of Half Moon Bay, California

This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of Half Moon map area, California. The vector data file is included in "Contours_OffshoreHalfMoonBay.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreSanGregorio/data_catalog_OffshoreSanGregorio.html.
10-m interval contours of the Offshore of Half Moon Bay map area, California, were generated from bathymetry data collected by Fugro Pelagos and by California State University, Monterey Bay, Seafloor Mapping Lab (CSUMB). Mapping was completed in 2006 and 2007, using a combination of 400-kHz Reson 7125 and 244-kHz Reson 8101 multibeam echosounders. These mapping missions combined to collect bathymetry 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 the merged 2-m bathymetric surface. The most continuous contour segments were preserved while smaller segments and isolated island polygons were excluded from the final output. Contours were smoothed via a polynomial approximation with exponential kernel (PAEK) algorithm using a tolerance value of 60 m. The contours were then clipped to the boundary of the map area. These data are not intended for navigational purposes.

本数据集为DS 781的组成部分，提供了加利福尼亚州半月湾外海域多张海底地形图的水深等深线数据。矢量数据文件包含于"Contours_OffshoreHalfMoonBay.zip"压缩包中，可通过http://pubs.usgs.gov/ds/781/OffshoreSanGregorio/data_catalog_OffshoreSanGregorio.html获取。

加利福尼亚州半月湾外海域的10米间隔水深等深线，由Fugro Pelagos公司与加利福尼亚州立大学蒙特雷湾分校海底测绘实验室（CSUMB）采集的水深数据生成。测绘工作于2006年及2007年完成，采用了400kHz Reson 7125与244kHz Reson 8101多波束测深仪的组合配置。本次测绘任务共采集了约10米等深线至加州州属水域3海里界限以外区域的水深数据。

10米间隔的水深等深线由合并后的2米分辨率水深表面数据生成。最终输出结果保留了连续性最优的等深线段，剔除了零散的短小线段与孤立岛屿多边形。等深线通过带指数核的多项式近似（Polynomial Approximation with Exponential Kernel, PAEK）算法进行平滑处理，平滑容差设置为60米。随后将生成的等深线裁切至本次测绘区域的边界范围内。

本数据集并非用于导航用途。