地球体与地图投影.ppt

Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * 为了保证一等三角锁有足够的精度，在锁段交叉处要测定起始边，其精度不低于1/350000，起始边可以由电磁波测距仪直接测定。在起始边的两端点测定天文经、纬度和天文方位角，并在锁段中央的一个点上测定天文经、纬度。天文经、纬度和天文方位角的测量误差都有一定的限制。凡测定天文经、纬度的点都为计算垂线偏差提供资料，这就是在控制网中进行天文观测的作用。由于水平控制网的布设中有天文观测，所以国家水平控制网又称天文大地网。 Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * Zhu Laing Cartography * * * （三）区域地图投影的选择 第3节 地图投影 第2章 地球体与地图投影 3. 伪圆锥投影 彭纳投影 中央经线与中央纬线没有变形； 纬线呈同心圆弧，长度比 n =1； 中央经线为直线，长度比 mλ=1； 其余经线对称于中央经线；每一条纬线上的经线间隔相等； 距离这两条