Utilities

CubicSpline(x, y)

Construct a cubic spline interpolator. x and y must have the same length and at least four elements.

Example

julia> x = 1:5;

julia> y = [2.0, 5.0, 3.2, 4.8, 6.7];

julia> spl = CubicSpline(x, y);

julia> spl(3.5)
3.5921875

days_to_hms(days)

Split days into hours, minutes, and seconds.

Example

julia> days_to_hms(0.314159)
(7, 32, 23.337600000000265)

deg_to_dms(x)

Split x into degrees, arcminutes, and arcseconds.

Example

julia> deg_to_dms(90.314159)
(90, 18, 50.97240000001307)

deg_to_rad(x)

Convert x from degrees to radians.

Example

julia> deg_to_rad(90)
1.5707963267948966

deg_to_sec(x)

Convert x from degrees to arcseconds.

Example

julia> deg_to_sec(90.0)
324000.0

distance(v1, v2)

Return the Euclidean (L2) distance between vectors v1 and v2.

Example

julia> distance([1.0, 0.0, 0.0], [0.0, 1.0, 0.0])
1.4142135623730951

dms_to_deg(d, m, s)

Convert degrees d, arcminutes m, and arcseconds s to degrees.

Example

julia> dms_to_deg(90, 18, 50.97240000001307)
90.314159

dms_to_rad(d, m, s)

Convert degrees d, arcminutes m, and arcseconds s to radians.

Example

julia> dms_to_rad(25, 42, 51.42857142857508)
0.4487989505128276

hms_to_days(h, m, s)

Convert hours h, minutes m, and seconds s to days.

Example

julia> hms_to_days(7, 32, 50.2)
0.3144699074074074

normalize2pi(angle[, center=0.0])

Normalize angle to be in the interval [center-π, center+π].

rad_to_deg(x)

Convert x from radians to degrees.

Example

julia> rad_to_deg(π/2)
90.0

rad_to_dms(x)

Convert x from radians into degrees, arcminutes, and arcseconds.

Example

julia> rad_to_dms(π/7)
(25, 42, 51.42857142857508)

rad_to_sec(x)

Convert x from radians to arcseconds.

Example

julia> rad_to_sec(π/2)
324000.0

sec_to_deg(x)

Convert x from arcseconds to degrees.

Example

julia> sec_to_deg(324000)
90.0

sec_to_rad(x)

Convert x from arcseconds to radians.

Example

julia> sec_to_rad(324000)
1.5707963267948966

spherical_to_cartesian(theta, phi)

Convert spherical coordinates to Cartesian.

Arguments

• theta: longitude angle in radians
• phi: latitude angle in radians

Returns

• x: magnitude of projection on x axis
• y: magnitude of projection on y axis
• z: magnitude of projection on z axis

References

• ERFA

angle(v1, v2)

Returns the angle between vectors v1 and v2 in rad.

Example

julia> rad_to_deg(angle([1.0, 0.0, 0.0], [0.0, 1.0, 0.0]))
90.0