@interact
def projectile(longitude=0 , latitude=0 , north_south=0 , west_east=0 , velocity=100):

	earth_r = 6371
    altitude = 100
	globe_color = "blue"
    coord_step = 30
	coord_color = "red"
	coord_weight = 8

	map = implicit_plot3d( x^2+y^2+z^2=earth_r^2 , (x,-(r+altitude),r+altitude) , (y,-(r+altitude),r+altitude) , (z,-(r+altitude),r+altitude) , opacity=.3 , color=globe_color )
    for i in srange( 0 , pi , coord_step*pi/180 ) :
        map += parametric_plot3d( ( earth_r*sin(t)*cos(i) , earth_r*sin(t)*cos(i) , earth_r*sin(t)*sin(i) ), (t,0,2*pi) , size=coord_weight , color=coord_color )
    for i in srange( -pi/2 , pi/2+.00001 , coord_step*pi/180 ) :
        map += parametric_plot3d( ( earth_r*cos(t)*cos(i) , earth_r*sin(t)*cos(i) , earth_r*sin(i) ) , (t,0,2*pi) , size=coord_weight , color=coord_color )

	p0 = ( earth_r*cos(longitude*pi/180)*cos(latitude*pi/180) , earth_r*sin(longitude*pi/180)*cos(latitude*pi/180) , earth_r*sin(latitude*pi/180) )

    position_arrow = arrow( (0,0,0) , p0 )

	d0 = vector([ cos((longitude+west_east)*pi/180)*cos((latitude+north_south)*pi/180) , sin((longitude+west_east)*pi/180)*cos((latitude+north_south)*pi/180) , sin((latitude+north_south)*pi/180) ])
    velocity_arrow = arrow( p0 , p0+d0*velocity )

    show(map)