Contours--Offshore of San Gregorio, California

This part of SIM 3306 presents data for the bathymetric contours for several seafloor maps (see sheets 1, 2, 3, 7, 10, SIM 3306) of the Offshore of San Gregorio map area, California. The vector data file is included in "Contours_OffshoreSanGregorio.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreSanGregorio/data_catalog_OffshoreSanGregorio.html.
10-m interval contours of the Offshore of San Gregorio 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.

本部分SIM 3306数据集提供了加利福尼亚州圣格雷戈里奥近海制图区多张海底地图的海底等深线（bathymetric contours）数据，具体对应SIM 3306中的工作表1、2、3、7、10。矢量数据文件收录于"Contours_OffshoreSanGregorio.zip"压缩包中，可通过http://pubs.usgs.gov/ds/781/OffshoreSanGregorio/data_catalog_OffshoreSanGregorio.html公开获取。

加利福尼亚州圣格雷戈里奥近海制图区的10米间隔海底等深线，由Fugro Pelagos公司与加利福尼亚州立大学蒙特利湾分校海底测绘实验室（CSUMB）采集的水深（bathymetry）数据生成。该测绘工作于2006年和2007年完成，采用了400kHz Reson 7125与244kHz Reson 8101多波束测深仪（multibeam echosounders）的组合方案。本次联合测绘任务采集了覆盖从约10米等深线（isobath）至超出加利福尼亚州管辖海域3海里界限区域的水深数据。研究人员基于合并后的2米分辨率水深表面生成了10米间隔的海底等深线，最终输出结果保留了连续性最优的等深线片段，剔除了零散小段及孤立岛状多边形。随后采用以60米为容差值的带指数核的多项式近似（Polynomial Approximation with Exponential Kernel，PAEK）算法对生成的等深线进行平滑处理，并将其裁剪至制图区域边界。