dtopotools_horiz_okada_and_1d.py 文件源码

def strike_direction(x1, y1, x2, y2):
    """
    Calculate strike direction between two points.
    Actually calculates "initial bearing" from (x1,y1) in direction
    towards (x2,y2), following
    http://www.movable-type.co.uk/scripts/latlong.html
    """

    x1 = x1*numpy.pi/180.
    y1 = y1*numpy.pi/180.
    x2 = x2*numpy.pi/180.
    y2 = y2*numpy.pi/180.
    dx = x2-x1
    theta = numpy.arctan2(numpy.sin(dx)*numpy.cos(y2), \
            numpy.cos(y1)*numpy.sin(y2) \
            - numpy.sin(y1)*numpy.cos(y2)*numpy.cos(dx))
    s = theta*180./numpy.pi
    if s<0:
        s = 360+s
    return s