Granulometric measurements of coastal boulders in various places in North Atlantic (V1)

In the framework of the project EXTREMEVENT, we measured the topographic and granulometric attributes of coastal boulders in various places in the Noth Atlantic : the coasts of the Reykjanes Peninsula (southwestern Iceland), the coasts of Brittany (western France). This dataset gathers these attributes as follow: - the date, the country, the region, and a site identifier; - the type of boulder (CTB = cliff-top boulder; SPB = supratidal platform boulder); - the X, Y and Z positions, measured with a differential global positioning system (DGPS) in real-time kinematic (RTK) mode (initially measured in a local coordinate reference system (EPSG:5326 in Iceland, EPSG:2154 in France) and then converted to EPSG:4326; altitudes are given in meters above mean sea level); - the length of the A (longest axis), B (intermediate axis) and C (shortest axis) axes of the boulders, measured with a measuring tape; - the inland distance, corresponding to the distance of each boulder's location from the nearest position of the highest astronomical tide level; - the density of the rock in which the boulders are made.在EXTREMEVENT项目框架下，我们针对北大西洋沿岸的冰岛西南部雷克雅内斯半岛海岸、法国西部布列塔尼海岸的海岸巨砾，开展了地形与粒度属性的测量工作。本数据集整合了如下属性： - 日期、所属国家、区域及站点标识符； - 巨砾类型（CTB：崖顶巨砾（cliff-top boulder）；SPB：潮上带平台巨砾（supratidal platform boulder）； - 采用实时动态（real-time kinematic, RTK）模式下的差分全球定位系统（differential global positioning system, DGPS）测量得到的X、Y、Z坐标（初始测量采用局部坐标参考系：冰岛为EPSG:5326，法国为EPSG:2154，后转换至EPSG:4326；海拔以平均海平面以上米数计量）； - 巨砾A轴（最长轴）、B轴（中间轴）与C轴（最短轴）的长度，由卷尺测量获得； - 内陆距离，即每块巨砾所在位置至最近的最高天文潮位位置的距离； - 巨砾所属岩石的密度。