Beach profile data for the Elwha River Delta, 2013-09-18

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).

本数据集采用全球导航卫星系统（GNSS）测量方法采集数据，所用差分全球定位系统（DGPS）运行于实时动态（RTK）模式。2013年之前的测量数据通常采用麦哲伦ProMark 3传统RTK-DGPS系统（即本地基准站与流动站）采集，基准站架设于1996年布设的测量控制标记点，其测量控制坐标参考北美大地基准84（NAD83(CORS91)）。自2013年起，测量数据通常采用连接至华盛顿州参考站网的AshTech ProMark 200 RTK-DGPS系统采集。2013年1月至11月间采集的测量数据参考北美大地基准84（NAD83(CORS96)），2013年11月之后采集的数据则参考北美大地基准84（NAD83(2011)）