| 摘要 |
PURPOSE:To simply decide a route, by a method wherein, from 2 position data each of 2 points on a spherical surface and one position data of one point on a segment of a line between the two points, other position data of a point on the segment of a line is computed, and the result is compared with a geo-navigation data. CONSTITUTION:A latitude omega of a point P on a segment of a line connecting two ports A and B on a globe is found by computation based on longitudes alpha, beta of the ports A and B, open angles psi, phi of the ports A and B from the extreme point, and the longutide of the point P, the result is compared with a marine chart data around the segment of the line connecting the two points A and B, and if the point P is found to be situated in a given area resulting from the check for the presence of the point P within the given area, an OK signal is obtained. If it is out of the given area, recomputation is made based on data of a different course connecting the two points A and B to decide the route. |
