
ACTION:
 Decode a freeformat sexagesimal string (degrees, arcminutes, arcseconds) into a
single precision floating point number (radians).

CALL:
CALL sla_AFIN (STRING, NSTRT, RESLT, JF)
GIVEN:
STRING  C*(*)  string containing deg, arcmin, arcsec fields 

NSTRT  I  pointer to start of decode (beginning of STRING =
1) 

RETURNED:
NSTRT  I  advanced past the decoded angle 

RESLT  R  angle in radians 

JF  I  status: 

  0 = OK 

 
$+1$
= default, RESLT unchanged (note 2) 

 
$1$
= bad degrees (note 3) 

 
$2$
= bad arcminutes (note 3) 

 
$3$
= bad arcseconds (note 3) 



EXAMPLE
 :
argument  before  after 

STRING  ${}^{\prime}$57␣17␣44.806␣␣12␣34␣56.7${}^{\prime}$  unchanged 
NSTRT  1  16 (i.e. pointing to 12...) 
RESLT    $1.00000$ 
JF    0 
A further call to sla_AFIN, without adjustment of NSTRT, will decode the second angle,
$12\circ \phantom{\rule{0.3em}{0ex}}3{4}^{\prime}\phantom{\rule{0.3em}{0ex}}$′′567.

NOTES:


(1)
 The first three “fields” in STRING are degrees, arcminutes, arcseconds, separated by
spaces or commas. The degrees field may be signed, but not the others. The decoding
is carried out by the sla_DFLTIN routine and is freeformat.

(2)
 Successive fields may be absent, defaulting to zero. For zero status, the only
combinations allowed are degrees alone, degrees and arcminutes, and all three fields
present. If all three fields are omitted, a status of +1 is returned and RESLT is
unchanged. In all other cases RESLT is changed.

(3)
 Range checking:
 The degrees field is not range checked. However, it is expected to be integral
unless the other two fields are absent.
 The arcminutes field is expected to be 059, and integral if the arcseconds field
is present. If the arcseconds field is absent, the arcminutes is expected to be
059.9999...
 The arcseconds field is expected to be 059.9999...
 Decoding continues even when a check has failed. Under these circumstances
the field takes the supplied value, defaulting to zero, and the result RESLT is
computed and returned.

(4)
 Further fields after the three expected ones are not treated as an error. The pointer NSTRT is
left in the correct state for further decoding with the present routine or with sla_DFLTIN
etc. See the example, above.

(5)
 If STRING contains hours, minutes, seconds instead of degrees etc, or if the required units
are turns (or days) instead of radians, the result RESLT should be multiplied as
follows:
for STRING  to obtain  multiply RESLT by 

$\circ $
${}^{\prime}$ ${}^{\u2033}$  radians  $1.0$ 
$\circ $
${}^{\prime}$ ${}^{\u2033}$  turns  $1/2\pi =0.1591549430918953358$ 
h m s  radians  $15.0$ 
h m s  days  $15/2\pi =2.3873241463784300365$ 
