C2S Subroutine

  1. astro_module.f90
  2. astro_module
  3. C2S

public subroutine C2S(p, theta, phi)

P-vector to spherical coordinates.

Status: vector/matrix support routine.

Notes

  1. P can have any magnitude; only its direction is used.

  2. If P is null, zero THETA and PHI are returned.

  3. At either pole, zero THETA is returned.

History

  • IAU SOFA revision: 2007 April 11

Arguments

TypeIntentOptionalAttributesName
real(kind=wp), intent(in), dimension(3):: p

p-vector
real(kind=wp), intent(out) :: theta

longitude angle (radians)
real(kind=wp), intent(out) :: phi

latitude angle (radians)

Called by

proc~~c2s~~CalledByGraph proc~c2s C2S proc~atciq ATCIQ proc~atciq->proc~c2s proc~fk54z FK54Z proc~fk54z->proc~c2s proc~aticqn ATICQN proc~aticqn->proc~c2s proc~eceq06 ECEQ06 proc~eceq06->proc~c2s proc~fk45z FK45Z proc~fk45z->proc~c2s proc~g2icrs G2ICRS proc~g2icrs->proc~c2s proc~lteqec LTEQEC proc~lteqec->proc~c2s proc~atioq ATIOQ proc~atioq->proc~c2s proc~atciqn ATCIQN proc~atciqn->proc~c2s proc~aticq ATICQ proc~aticq->proc~c2s proc~atciqz ATCIQZ proc~atciqz->proc~c2s proc~atoiq ATOIQ proc~atoiq->proc~c2s proc~eqec06 EQEC06 proc~eqec06->proc~c2s proc~fk5hz FK5HZ proc~fk5hz->proc~c2s proc~icrs2g ICRS2G proc~icrs2g->proc~c2s proc~lteceq LTECEQ proc~lteceq->proc~c2s proc~p2s P2S proc~p2s->proc~c2s proc~atci13 ATCI13 proc~atci13->proc~atciq proc~atco13 ATCO13 proc~atco13->proc~atciq proc~atco13->proc~atioq proc~atic13 ATIC13 proc~atic13->proc~aticq proc~atio13 ATIO13 proc~atio13->proc~atioq proc~atoi13 ATOI13 proc~atoi13->proc~atoiq proc~atoc13 ATOC13 proc~atoc13->proc~aticq proc~atoc13->proc~atoiq

Contents

Source Code

C2S

Source Code

    subroutine C2S ( p, theta, phi )

    implicit none

    real(wp),dimension(3),intent(in) :: p !! p-vector
    real(wp),intent(out) :: theta !! longitude angle (radians)
    real(wp),intent(out) :: phi !! latitude angle (radians)

    real(wp) :: x, y, z, d2

    x = p(1)
    y = p(2)
    z = p(3)
    d2 = x*x + y*y

    if ( d2 == 0.0_wp ) then
       theta = 0.0_wp
    else
       theta = atan2(y,x)
    end if

    if ( z == 0.0_wp ) then
       phi = 0.0_wp
    else
       phi = atan2(z,sqrt(d2))
    end if

    end subroutine C2S