Contours--Offshore of Pacifica, California

This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of Pacifica map area, California. The vector data file is included in "Contours_OffshorePacifica.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshorePacifica/data_catalog_OffshorePacifica.html.

10-m interval contours of the Offshore of Pacifica 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 between 2005 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，涵盖加利福尼亚州帕西菲卡近海（Offshore of Pacifica）多个海底地形图的水深等值线（bathymetric contours）数据。矢量数据文件打包于"Contours_OffshorePacifica.zip"压缩包内，可通过http://pubs.usgs.gov/ds/781/OffshorePacifica/data_catalog_OffshorePacifica.html获取。

加利福尼亚州帕西菲卡近海制图区域的10米间隔水深等值线，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（California State University, Monterey Bay, Seafloor Mapping Lab，CSUMB）采集的水深数据生成。测绘工作于2005年至2007年间完成，采用400kHz Reson 7125与244kHz Reson 8101多波束测深仪（multibeam echosounders）组合设备开展作业。本次测绘任务共采集了约10米等深线（isobath）至加州州域3海里界限以外区域的水深数据。10米间隔的水深等值线由融合后的2米分辨率水深曲面生成，最终成果保留了连续性最优的等值线段，剔除了短小线段与孤立岛状多边形。随后采用指数核多项式近似（Polynomial Approximation with Exponential Kernel，PAEK）算法，以60米为容差对等值线进行平滑处理，并将等值线裁剪至制图区域边界。本数据集并非用于导航用途。