Beach profile data for the Elwha River Delta, 2011-05-18

Data were collected using GNSS survey methods, with a differential GPS operating in Real Time Kinematic (RTK) mode. Data from prior to 2013 were typically collected with a Magellan ProMark 3 traditional RKT-DGPS system (i.e. local base station and rover), with the base station sited on survey control markers installed in 1996, with survey control coordinates referenced to NAD83(CORS91). Starting in 2013 survey data were typically collected with an AshTech ProMark 200 RTK-DGPS system connected to the Washington State Reference Network. Survey data collected between January and November 2013 are referenced to NAD83(CORS96), and after November 2013 to NAD83(2011).

数据采用全球导航卫星系统（GNSS）测量方法采集，使用的差分全球定位系统（GPS）工作于实时动态（RTK）模式。2013年之前的数据通常采用Magellan ProMark 3传统RKT-DGPS系统（即本地基站与移动站）采集，基站布设在1996年安装的测量控制点上，测量控制坐标参考NAD83(CORS91)坐标系。2013年起，测量数据通常采用连接至华盛顿州参考网（Washington State Reference Network）的AshTech ProMark 200 RTK-DGPS系统采集。2013年1月至11月采集的测量数据参考NAD83(CORS96)坐标系，2013年11月之后的则参考NAD83(2011)坐标系。