/* getfov.f -- translated by f2c (version 19980913).
   You must link the resulting object file with the libraries:
	-lf2c -lm   (in that order)
*/

#include "f2c.h"

/* Table of constant values */

static integer c__1 = 1;
static integer c__4 = 4;
static integer c__3 = 3;
static integer c__0 = 0;

/* $Procedure GETFOV ( Fetch instrument FOV parameters ) */
/* Subroutine */ int getfov_(integer *instid, integer *room, char *shape, 
	char *frame, doublereal *bsight, integer *n, doublereal *bounds, 
	ftnlen shape_len, ftnlen frame_len)
{
    /* Initialized data */

    static char shapid[32*4] = "CIRCLE                          " "ELLIPSE  "
	    "                       " "POLYGON                         " "REC"
	    "TANGLE                       ";
    static char angshp[32*3] = "CIRCLE                          " "ELLIPSE  "
	    "                       " "RECTANGLE                       ";

    /* System generated locals */
    doublereal d__1;

    /* Builtin functions */
    /* Subroutine */ int s_copy(char *, char *, ftnlen, ftnlen);
    integer s_cmp(char *, char *, ftnlen, ftnlen);
    double cos(doublereal), sin(doublereal);

    /* Local variables */
    doublereal bmag;
    char spec[80];
    doublereal vmag;
    extern /* Subroutine */ int vhat_(doublereal *, doublereal *), vscl_(
	    doublereal *, doublereal *, doublereal *), vequ_(doublereal *, 
	    doublereal *);
    char type__[1];
    doublereal b[3];
    integer i__;
    extern /* Subroutine */ int chkin_(char *, ftnlen), ucase_(char *, char *,
	     ftnlen, ftnlen), errch_(char *, char *, ftnlen, ftnlen);
    logical found;
    extern /* Subroutine */ int repmi_(char *, char *, integer *, char *, 
	    ftnlen, ftnlen, ftnlen), vlcom_(doublereal *, doublereal *, 
	    doublereal *, doublereal *, doublereal *);
    doublereal b1[3], b2[3];
    integer mxcmp;
    char kword[32];
    extern /* Subroutine */ int vperp_(doublereal *, doublereal *, doublereal 
	    *);
    extern integer rtrim_(char *, ftnlen);
    extern logical eqstr_(char *, char *, ftnlen, ftnlen);
    extern /* Subroutine */ int vcrss_(doublereal *, doublereal *, doublereal 
	    *);
    extern doublereal vnorm_(doublereal *);
    extern /* Subroutine */ int ljust_(char *, char *, ftnlen, ftnlen), 
	    unorm_(doublereal *, doublereal *, doublereal *), vrotv_(
	    doublereal *, doublereal *, doublereal *, doublereal *);
    doublereal refang;
    extern integer bsrchc_(char *, integer *, char *, ftnlen, ftnlen);
    doublereal coscan;
    char kwcang[32];
    doublereal refvec[3], sincan, crsang;
    extern /* Subroutine */ int gcpool_(char *, integer *, integer *, integer 
	    *, char *, logical *, ftnlen, ftnlen), gdpool_(char *, integer *, 
	    integer *, integer *, doublereal *, logical *, ftnlen);
    doublereal cosran, tmpang;
    char kwfram[32], kwbore[32], angunt[80], kwrang[32], kwrvec[32], kwshap[
	    32], kwboun[32], kwspec[32];
    doublereal normal[12]	/* was [3][4] */, sinran;
    char kwaunt[32];
    doublereal tmpvec[3];
    extern /* Subroutine */ int setmsg_(char *, ftnlen), errint_(char *, 
	    integer *, ftnlen), sigerr_(char *, ftnlen), chkout_(char *, 
	    ftnlen);
    extern logical return_(void);
    extern /* Subroutine */ int dtpool_(char *, logical *, integer *, char *, 
	    ftnlen, ftnlen), suffix_(char *, integer *, char *, ftnlen, 
	    ftnlen), convrt_(doublereal *, char *, char *, doublereal *, 
	    ftnlen, ftnlen);

/* $ Abstract */

/*     This subroutine returns the field-of-view (FOV) parameters for */
/*     a specified instrument. */

/* $ Disclaimer */

/*     THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
/*     CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
/*     GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
/*     ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
/*     PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
/*     TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
/*     WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
/*     PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
/*     SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
/*     SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */

/*     IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
/*     BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
/*     LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
/*     INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
/*     REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
/*     REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */

/*     RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
/*     THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
/*     CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
/*     ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */

/* $ Required_Reading */

/*     IK */

/* $ Keywords */

/*     INSTRUMENT */

/* $ Declarations */
/* $ Brief_I/O */

/*     VARIABLE  I/O  DESCRIPTION */
/*     --------  ---  -------------------------------------------------- */
/*     INSTID     I   NAIF ID of an instrument */
/*     ROOM       I   Maximum number of vectors that can be returned. */
/*     SHAPE      O   Instrument FOV shape. */
/*     FRAME      O   Name of the frame in which FOV vectors are defined. */
/*     BSIGHT     O   Boresight vector. */
/*     N          O   Number of boundary vectors returned. */
/*     BOUNDS     O   FOV boundary vectors. */

/* $ Detailed_Input */

/*     INSTID     is the NAIF ID of an instrument. */

/*     ROOM       is the maximum number of 3D vectors that can be */
/*                returned in BOUNDS. */

/* $ Detailed_Output */

/*     SHAPE      is a character string that describes the "shape" of */
/*                the field of view.  Possible values returned are: */

/*                   'POLYGON' */
/*                   'RECTANGLE' */
/*                   'CIRCLE' */
/*                   'ELLIPSE' */

/*                If the value of SHAPE is 'POLYGON' the field of view */
/*                of the instrument is a pyramidal polyhedron. The */
/*                vertex of the pyramid is at the instrument focal */
/*                point. The rays along the edges of the pyramid are */
/*                parallel to the vectors returned in BOUNDS. */

/*                If the value of SHAPE is 'RECTANGLE' the field of view */
/*                of the instrument is a rectangular pyramid. The vertex */
/*                of the pyramid is at the instrument focal point. The */
/*                rays along the edges of the pyramid are parallel to */
/*                the vectors returned in BOUNDS.  Moreover, in this */
/*                case, the boresight points along the axis of symmetry */
/*                of the rectangular pyramid. */

/*                If the value of SHAPE is 'CIRCLE' the field of view of */
/*                the instrument is a circular cone about the boresight */
/*                vector. The vertex of the cone is at the instrument */
/*                focal point. A single vector will be returned in */
/*                BOUNDS.  This vector will be parallel to a ray that */
/*                lies in the cone that makes up the boundary of the */
/*                field of view. */

/*                If the value of SHAPE is 'ELLIPSE' the field of view */
/*                of the instrument is a elliptical cone with the */
/*                boresight vector as the axis of the cone.  In this */
/*                case two vectors are returned in BOUNDS. One of the */
/*                vectors returned in BOUNDS points to the end of the */
/*                semi-major axis of a perpendicular cross section of */
/*                the elliptic cone.  The other vector points to the end */
/*                of the semi-minor axis of a perpendicular cross */
/*                section of the cone. */

/*     FRAME      is the name of the reference frame in which the field */
/*                of view boundary vectors are defined. */

/*     BSIGHT     is a vector that points in the direction of the */
/*                center of the field of view.  The length of BSIGHT */
/*                is not specified other than being non-zero. */

/*     N          is the number of boundary vectors returned. */

/*     BOUNDS     is an array of vectors that point to the "corners" of */
/*                the instrument field of view.  (See the discussion */
/*                accompanying shape for an expansion of the term */
/*                "corner of the field of view.")  Note that the vectors */
/*                returned in BOUNDS are not necessarily unit vectors. */

/* $ Parameters */

/*     MINCOS     This parameter is the lower limit on the value of the */
/*                cosine of the cross or reference angles in the ANGLES */
/*                specification cases. (see Particulars for further */
/*                discussion). */
/* $ Exceptions */

/*     1) The error SPICE(FRAMEMISSING) is signaled if the frame */
/*        associated with the instrument can not be found in the kernel */
/*        pool. */

/*     2) The error SPICE(SHAPEMISSING) is signaled if the shape of the */
/*        instrument field of view can not be found in the kernel pool. */

/*     3) The error 'SPICE(SHAPENOTSUPPORTED)' is signaled if the shape */
/*        specified by the instrument kernel is not one of the four */
/*        values: 'CIRCLE', 'POLYGON', 'ELLIPSE', 'RECTANGLE'.   If the */
/*        ANGLES specification is used it must be: 'CIRCLE', 'ELLIPSE', */
/*        or 'RECTANGLE'. */

/*     4) The error 'SPICE(BORESIGHTMISSING)' is signaled if */
/*        the direction of the boresight cannot be located in the */
/*        kernel pool. */

/*     5) The error 'SPICE(BADBORESIGHTSPEC)' is signaled if */
/*        the number of components for the boresight vector */
/*        in the kernel pool is not 3. */

/*     6) The error 'SPICE(BOUNDARYMISSING)' is signaled if */
/*        the boundary vectors for the edge of the field of view */
/*        cannot be found in the kernel pool. */

/*     7) The error 'SPICE(BOUNDARYTOOBIG)' is signaled if there */
/*        is insufficient room (as specified by the variable ROOM) */
/*        to return all of the vectors associated with the boundary */
/*        of the field of view. */

/*     8) The error 'SPICE(BADBOUNDARY)' is signaled if the number */
/*        of components of vectors making up the field of view is */
/*        not a multiple of 3. */

/*     9) The error 'SPICE(BADBOUNDARY)' is signaled if the number */
/*        of components of vectors making up the field of view is */
/*        not compatible with the shape specified for the field of */
/*        view. */

/*    10) The error 'SPICE(REFVECTORMISSING)' is signaled if the */
/*        reference vector for the ANGLES spec can not be found */
/*        in the kernel pool. */

/*    11) The error 'SPICE(BADREFVECTORSPEC)' is signaled if the */
/*        reference vector stored in the kernel pool to support */
/*        the ANGLES spec contains an in correct number of components, */
/*        contains 3 character components, or is parallel to the */
/*        boresight. */

/*    12) The error 'SPICE(REFANGLEMISSING)' is signaled if the */
/*        reference angle stored in the kernel pool to support */
/*        the ANGLES spec is absent from the kernel pool. */

/*    13) The error 'SPICE(UNITSMISSING)' is signaled if the */
/*        keyword that stores the angular units for the angles */
/*        used in the ANGLES spec is absent from the kernel pool. */

/*    14) The error 'SPICE(CROSSANGLEMISSING)' is signaled if the */
/*        keyword that stores the cross angle for the ANGLES spec */
/*        is needed and is absent from the kernel pool. */

/*    15) The error 'SPICE(BADBOUNDARY)' is signaled if the angles */
/*        for the RECTANGLE/ANGLES spec case have cosines that */
/*        are less than those stored in the parameter MINCOS. */

/*    16) The error 'SPICE(UNSUPPORTEDSPEC)' is signaled if the */
/*        class specification contains something other than 'ANGLES' */
/*        or 'CORNERS'. */

/*    17) In the event that the CLASS_SPEC keyword is absent from the */
/*        kernel pool for the instrument whose FOV is sought, this */
/*        module assumes the default CORNERS specification is to be */
/*        utilized. */

/* $ Files */

/*     This routine relies upon having successfully loaded an instrument */
/*     kernel (IK-file) via the routine FURNSH prior to calling this */
/*     routine. */

/* $ Particulars */

/*     This routine provides a common interface to retrieving */
/*     the geometric characteristics of an instrument field of */
/*     view for a wide variety of remote sensing instruments */
/*     across many different space missions. */

/*     Given the NAIF instrument ID, (and having "loaded" the */
/*     instrument field of view description via the routine FURNSH) */
/*     this routine returns the bore-sight of the instrument, the */
/*     "shape" of the field of view, a collection of vectors */
/*     that point along the edges of the field of view, and the */
/*     name of the reference frame in which these vectors are defined. */

/*     Currently this routine supports two classes of specifications */
/*     for FOV definitions: "corners" and "angles". */

/*     The "corners" specification requires the following keywords */
/*     defining the shape, boresight, boundary vectors, and reference */
/*     frame of the FOV be provided in one of the text kernel files */
/*     (normally an IK file) loaded into the kernel pool (in the */
/*     keywords below <INSTID> is replaced with the instrument ID as */
/*     passed into the module): */

/*        INS<INSTID>_FOV_CLASS_SPEC         must be set to 'CORNERS' or */
/*                                           omitted to indicate the */
/*                                           "corners"-class */
/*                                           specification. */


/*        INS<INSTID>_FOV_SHAPE              must be set to one of these */
/*                                           values: */

/*                                              'CIRCLE' */
/*                                              'ELLIPSE' */
/*                                              'RECTANGLE' */
/*                                              'POLYGON' */

/*        INS<INSTID>_FOV_FRAME              must contain the name of */
/*                                           the frame in which the */
/*                                           boresight and boundary */
/*                                           corner vectors are defined. */

/*        INS<INSTID>_BORESIGHT              must be set to a 3D vector */
/*                                           defining the boresight in */
/*                                           the FOV frame specified in */
/*                                           the FOV_FRAME keyword. */

/*        INS<INSTID>_FOV_BOUNDARY   or */
/*        INS<INSTID>_FOV_BOUNDARY_CORNERS   must be set to one (for */
/*                                           FOV_SHAPE = 'CIRCLE'), two */
/*                                           (for FOV_SHAPE = */
/*                                           'ELLIPSE'), three (for */
/*                                           FOV_SHAPE = 'RECTANGLE'), */
/*                                           or three or more (for */
/*                                           'POLYGON') 3D vectors */
/*                                           defining the corners of the */
/*                                           FOV in the FOV frame */
/*                                           specified in the FOV_FRAME */
/*                                           keyword. */

/*     The "angles" specification requires the following keywords */
/*     defining the shape, boresight, reference vector, reference and */
/*     cross angular extents of the FOV be provided in one of the text */
/*     kernel files (normally an IK file) loaded into the kernel */
/*     pool (in the keywords below <INSTID> is replaced with the */
/*     instrument ID as passed into the module): */

/*        INS<INSTID>_FOV_CLASS_SPEC         must be set to  'ANGLES' to */
/*                                           indicate the "angles"-class */
/*                                           specification. */

/*        INS<INSTID>_FOV_SHAPE              must be set to one of these */
/*                                           values: */

/*                                              'CIRCLE' */
/*                                              'ELLIPSE' */
/*                                              'RECTANGLE' */

/*        INS<INSTID>_FOV_FRAME              must contain the name of */
/*                                           the frame in which the */
/*                                           boresight and the computed */
/*                                           boundary corner vectors are */
/*                                           defined. */

/*        INS<INSTID>_BORESIGHT              must be set to a 3D vector */
/*                                           defining the boresight in */
/*                                           the FOV frame specified in */
/*                                           the FOV_FRAME keyword. */

/*        INS<INSTID>_FOV_REF_VECTOR         must be set to a 3D vector */
/*                                           that together with the */
/*                                           boresight vector defines */
/*                                           the plane in which the */
/*                                           first angular extent of the */
/*                                           FOV specified in the */
/*                                           FOV_REF_ANGLE keyword is */
/*                                           measured. */

/*        INS<INSTID>_FOV_REF_ANGLE          must be set to the angle */
/*                                           that is 1/2 of the total */
/*                                           FOV angular extent in the */
/*                                           plane defined by the */
/*                                           boresight and the vector */
/*                                           specified in the */
/*                                           FOV_REF_VECTOR keyword. */

/*        INS<INSTID>_FOV_CROSS_ANGLE        must be set to the angle */
/*                                           that is 1/2 of the total */
/*                                           FOV angular extent in the */
/*                                           plane containing the */
/*                                           boresight and perpendicular */
/*                                           to the plane defined by the */
/*                                           boresight and the vector */
/*                                           specified in the */
/*                                           FOV_REF_VECTOR keyword. */
/*                                           This keyword is not */
/*                                           required for FOV_SHAPE = */
/*                                           'CIRCLE'. */

/*        INS<INSTID>_FOV_ANGLE_UNITS        must specify units for the */
/*                                           angles given in the */
/*                                           FOV_REF_ANGLE and */
/*                                           FOV_CROSS_ANGLE keywords. */
/*                                           Any angular units */
/*                                           recognized by CONVRT are */
/*                                           acceptable. */

/*     This routine is intended to be an intermediate level routine. */
/*     It is expected that users of this routine will be familiar */
/*     with the SPICE frames subsystem and will be comfortable writing */
/*     software to further manipulate the vectors retrieved by this */
/*     routine. */

/* $ Examples */

/*     The example program in this section loads the IK file */
/*     'example.ti' with the following contents defining four FOVs of */
/*     various shapes and sizes: */

/*        KPL/IK */

/*        The keywords below define a circular, 10-degree wide FOV with */
/*        the boresight along the +Z axis of the 'SC999_INST001' frame */
/*        for an instrument with ID -999001 using the "angles"-class */
/*        specification. */

/*        \begindata */
/*           INS-999001_FOV_CLASS_SPEC       = 'ANGLES' */
/*           INS-999001_FOV_SHAPE            = 'CIRCLE' */
/*           INS-999001_FOV_FRAME            = 'SC999_INST001' */
/*           INS-999001_BORESIGHT            = ( 0.0, 0.0, 1.0 ) */
/*           INS-999001_FOV_REF_VECTOR       = ( 1.0, 0.0, 0.0 ) */
/*           INS-999001_FOV_REF_ANGLE        = ( 5.0 ) */
/*           INS-999001_FOV_ANGLE_UNITS      = ( 'DEGREES' ) */
/*        \begintext */

/*        The keywords below define an elliptical FOV with 2- and */
/*        4-degree angular extents in the XZ and XY planes and the */
/*        boresight along the +X axis of the 'SC999_INST002' frame for */
/*        an instrument with ID -999002 using the "corners"-class */
/*        specification. */

/*        \begindata */
/*           INS-999002_FOV_SHAPE            = 'ELLIPSE' */
/*           INS-999002_FOV_FRAME            = 'SC999_INST002' */
/*           INS-999002_BORESIGHT            = ( 1.0, 0.0, 0.0 ) */
/*           INS-999002_FOV_BOUNDARY_CORNERS = ( 1.0, 0.0, 0.01745506, */
/*                                               1.0, 0.03492077, 0.0 ) */
/*        \begintext */

/*        The keywords below define a rectangular FOV with 1.2- and */
/*        0.2-degree angular extents in the ZX and ZY planes and the */
/*        boresight along the +Z axis of the 'SC999_INST003' frame for */
/*        an instrument with ID -999003 using the "angles"-class */
/*        specification. */

/*        \begindata */
/*           INS-999003_FOV_CLASS_SPEC       = 'ANGLES' */
/*           INS-999003_FOV_SHAPE            = 'RECTANGLE' */
/*           INS-999003_FOV_FRAME            = 'SC999_INST003' */
/*           INS-999003_BORESIGHT            = ( 0.0, 0.0, 1.0 ) */
/*           INS-999003_FOV_REF_VECTOR       = ( 1.0, 0.0, 0.0 ) */
/*           INS-999003_FOV_REF_ANGLE        = ( 0.6 ) */
/*           INS-999003_FOV_CROSS_ANGLE      = ( 0.1 ) */
/*           INS-999003_FOV_ANGLE_UNITS      = ( 'DEGREES' ) */
/*        \begintext */

/*        The keywords below define a triangular FOV with the boresight */
/*        along the +Y axis of the 'SC999_INST004' frame for an */
/*        instrument with ID -999004 using the "corners"-class */
/*        specification. */

/*        \begindata */
/*           INS-999004_FOV_SHAPE            = 'POLYGON' */
/*           INS-999004_FOV_FRAME            = 'SC999_INST004' */
/*           INS-999004_BORESIGHT            = (  0.0,  1.0,  0.0 ) */
/*           INS-999004_FOV_BOUNDARY_CORNERS = (  0.0,  0.8,  0.5, */
/*                                                0.4,  0.8, -0.2, */
/*                                               -0.4,  0.8, -0.2 ) */
/*        \begintext */

/*     The program shown below loads the IK, fetches parameters for each */
/*     of the four FOVs and prints these parameters to the screen. */

/*        IMPLICIT              NONE */

/*        INTEGER               MAXBND */
/*        PARAMETER           ( MAXBND = 4 ) */

/*        INTEGER               NUMINS */
/*        PARAMETER           ( NUMINS = 4 ) */

/*        INTEGER               WDSIZE */
/*        PARAMETER           ( WDSIZE = 32 ) */

/*        CHARACTER*(WDSIZE)    FRAME */
/*        CHARACTER*(WDSIZE)    SHAPE */

/*        DOUBLE PRECISION      BOUNDS ( 3, MAXBND ) */
/*        DOUBLE PRECISION      BSIGHT ( 3 ) */

/*        INTEGER               I */
/*        INTEGER               INSIDS ( NUMINS ) */
/*        INTEGER               J */
/*        INTEGER               N */

/*        DATA INSIDS / -999001, -999002, -999003, -999004 / */

/*        CALL FURNSH( 'example.ti' ) */

/*        WRITE (*,*) '--------------------------------------' */
/*        DO I = 1, NUMINS */

/*           CALL GETFOV ( INSIDS(I), MAXBND, */
/*       .                 SHAPE, FRAME, BSIGHT, N, BOUNDS ) */

/*           WRITE (*,*) 'Instrument ID: ', INSIDS(I) */
/*           WRITE (*,*) '    FOV shape: ', SHAPE */
/*           WRITE (*,*) '    FOV frame: ', frame */
/*           WRITE (*,*) 'FOV boresight: ', BSIGHT */
/*           WRITE (*,*) '  FOV corners: ' */
/*           DO J = 1, N */
/*              WRITE (*,*) '               ', */
/*       .                  BOUNDS(1,J), BOUNDS(2,J), BOUNDS(3,J) */
/*           END DO */
/*           WRITE (*,*) '--------------------------------------' */

/*        END DO */

/*        END */

/*     The program produces the following output: */

/*        -------------------------------------- */
/*        Instrument ID:  -999001 */
/*            FOV shape: CIRCLE */
/*            FOV frame: SC999_INST001 */
/*        FOV boresight:   0.  0.  1. */
/*          FOV corners: */
/*                         0.0871557427  0.  0.996194698 */
/*        -------------------------------------- */
/*        Instrument ID:  -999002 */
/*            FOV shape: ELLIPSE */
/*            FOV frame: SC999_INST002 */
/*        FOV boresight:   1.  0.  0. */
/*          FOV corners: */
/*                         1.  0.  0.01745506 */
/*                         1.  0.03492077  0. */
/*        -------------------------------------- */
/*        Instrument ID:  -999003 */
/*            FOV shape: RECTANGLE */
/*            FOV frame: SC999_INST003 */
/*        FOV boresight:   0.  0.  1. */
/*          FOV corners: */
/*                         0.0104717682  0.00174523267  0.999943647 */
/*                        -0.0104717682  0.00174523267  0.999943647 */
/*                        -0.0104717682 -0.00174523267  0.999943647 */
/*                         0.0104717682 -0.00174523267  0.999943647 */
/*        -------------------------------------- */
/*        Instrument ID:  -999004 */
/*            FOV shape: POLYGON */
/*            FOV frame: SC999_INST004 */
/*        FOV boresight:   0.  1.  0. */
/*          FOV corners: */
/*                         0.  0.8  0.5 */
/*                         0.4  0.8 -0.2 */
/*                        -0.4  0.8 -0.2 */
/*        -------------------------------------- */

/* $ Restrictions */

/*     An I-kernel for the instrument specified in INSTID must have been */
/*     loaded via a call to FURNSH prior to calling this routine and */
/*     must contain the specification for the instrument field of view */
/*     consistent with the expectations of this routine. */

/* $ Literature_References */

/*     None. */

/* $ Author_and_Institution */

/*     C.H. Acton   (JPL) */
/*     N.J. Bachman (JPL) */
/*     B.V. Semenov (JPL) */
/*     W.L. Taber   (JPL) */
/*     F.S. Turner  (JPL) */

/* $ Version */

/* -    SPICELIB Version 2.1.1  05-FEB-2009 (BVS) */

/*        Header updates: added information about required IK keywords; */
/*        replaced old example with a new one more focused on GETFOV and */
/*        IK keywords. */

/* -    SPICELIB Version 2.1.0  23-OCT-2005 (NJB) (BVS) */

/*        Fixed bug causing incorrect computation of the boundary */
/*        vectors for a rectangular FOV specified using the angular */
/*        extents method if the reference vector was provided as a */
/*        non-unit vector and/or was non-perpendicular to the */
/*        specified boresight. */

/*        Updated to remove non-standard use of duplicate arguments */
/*        in CONVRT, UNORM, VHAT, VSCL and VCROSS calls. */

/*        Replaced header reference to LDPOOL with reference to FURNSH. */

/* -    SPICELIB Version 2.0.1  29-JUL-2003 (NJB) (CHA) */

/*        Various header changes were made to improve clarity.  Some */
/*        minor header corrections were made. */

/* -    SPICELIB Version 2.0.0  15-MAY-2001 (FST) */

/*        Updated the routine to support the new ANGLES specification */
/*        for RECTANGLE, ELLIPSE, and CIRCLE. */

/* -    SPICELIB Version 1.1.2  10-MAY-2000 (WLT) */

/*        Removed the unused variable INDEX. */

/* -    SPICELIB Version 1.1.1  13-APR-2000 (WLT) */

/*        This routine was harvested from the NEAR specific routine */
/*        of the same name.  It was enhanced to support the 'RECTANGLE' */
/*        shape for a field of view (a special case of 'POLYGON' */
/*        added for the sake of Cassini users). */

/* -& */
/* $ Index_Entries */

/*     return instrument's FOV parameters */

/* -& */
/* $ Revisions */

/* -    SPICELIB Version 2.1.0  23-OCT-2005 (NJB) (BVS) */

/*        Fixed bug causing incorrect computation of the boundary */
/*        vectors for a rectangular FOV specified using the angular */
/*        extents method if the reference vector was provided as a */
/*        non-unit vector and/or was non-perpendicular to the */
/*        specified boresight. */

/*        Updated to remove non-standard use of duplicate arguments */
/*        in CONVRT, UNORM, VHAT, VSCL and VCROSS calls. */

/*        Replaced header reference to LDPOOL with reference to FURNSH. */

/* -& */

/*     SPICELIB functions */


/*     Local parameters */


/*     Keyword Name Length. */


/*     Maximum Number of Normal Vectors. */


/*     Number of CORNER Shapes Supported. */


/*     Number of ANGLE Shapes Supported. */


/*     Maximum Length of String Data from the kernel pool. */


/*     Local variables */


/*     Allowed values of shape identifier. Note that these must be */
/*     supplied in ascending order */


/*     Allowed values of the shape identifier for the ANGLES */
/*     specification.  Note that these must be supplied in ascending */
/*     order. */


/*     Standard SPICE error handling. */

    if (return_()) {
	return 0;
    } else {
	chkin_("GETFOV", (ftnlen)6);
    }
    s_copy(kwboun, "INS#_FOV_BOUNDARY", (ftnlen)32, (ftnlen)17);
    s_copy(kwbore, "INS#_BORESIGHT", (ftnlen)32, (ftnlen)14);
    s_copy(kwshap, "INS#_FOV_SHAPE", (ftnlen)32, (ftnlen)14);
    s_copy(kwfram, "INS#_FOV_FRAME", (ftnlen)32, (ftnlen)14);
    s_copy(kwspec, "INS#_FOV_CLASS_SPEC", (ftnlen)32, (ftnlen)19);
    s_copy(kwrvec, "INS#_FOV_REF_VECTOR", (ftnlen)32, (ftnlen)19);
    s_copy(kwrang, "INS#_FOV_REF_ANGLE", (ftnlen)32, (ftnlen)18);
    s_copy(kwcang, "INS#_FOV_CROSS_ANGLE", (ftnlen)32, (ftnlen)20);
    s_copy(kwaunt, "INS#_FOV_ANGLE_UNITS", (ftnlen)32, (ftnlen)20);
    mxcmp = *room * 3;

/*     Look for the frame keyword and get frame name if found, */
/*     complain if not. */

    repmi_(kwfram, "#", instid, kword, (ftnlen)32, (ftnlen)1, (ftnlen)32);
    gcpool_(kword, &c__1, &c__1, &i__, frame, &found, (ftnlen)32, frame_len);
    if (! found) {
	setmsg_("The variable, '#', specifying the frame which instrument # "
		"FOV components are defined relative to was not found in the "
		"kernel pool. Check whether IK file for the instrument was lo"
		"aded into the program and whether this variable is specified"
		" in that file.", (ftnlen)253);
	errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	errint_("#", instid, (ftnlen)1);
	sigerr_("SPICE(FRAMEMISSING)", (ftnlen)19);
	chkout_("GETFOV", (ftnlen)6);
	return 0;
    }

/*     Look for the shape keyword and get shape identifier if found, */
/*     complain if not. */

    repmi_(kwshap, "#", instid, kword, (ftnlen)32, (ftnlen)1, (ftnlen)32);
    gcpool_(kword, &c__1, &c__1, &i__, shape, &found, (ftnlen)32, shape_len);
    if (! found) {
	setmsg_("The variable, '#', specifying the shape of the instrument #"
		" FOV was not found in the kernel pool. Check whether IK file"
		" for the instrument was loaded into the program and whether "
		"this variable is specified in that file.", (ftnlen)219);
	errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	errint_("#", instid, (ftnlen)1);
	sigerr_("SPICE(SHAPEMISSING)", (ftnlen)19);
	chkout_("GETFOV", (ftnlen)6);
	return 0;
    }

/*     Create an upper case, left justified value for SHAPE.  This will */
/*     provide the desired case-insensitivity to the keyword value. */

    ucase_(shape, shape, shape_len, shape_len);
    ljust_(shape, shape, shape_len, shape_len);

/*     Check whether shape identified that we got is one from the list */
/*     of supported, complain if not. */

    if (bsrchc_(shape, &c__4, shapid, rtrim_(shape, shape_len), (ftnlen)32) ==
	     0) {
	setmsg_("The FOV shape, '#', specified in the keyword, '#', for the "
		"instrument # is not supported. See GETFOV subroutine header "
		"for the list of supported instrument FOV shapes.", (ftnlen)
		167);
	errch_("#", shape, (ftnlen)1, rtrim_(shape, shape_len));
	errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	errint_("#", instid, (ftnlen)1);
	sigerr_("SPICE(SHAPENOTSUPPORTED)", (ftnlen)24);
	chkout_("GETFOV", (ftnlen)6);
	return 0;
    }

/*     Look for the boresight keyword and get boresight vector if found, */
/*     complain if not. */

    repmi_(kwbore, "#", instid, kword, (ftnlen)32, (ftnlen)1, (ftnlen)32);
    dtpool_(kword, &found, &i__, type__, (ftnlen)32, (ftnlen)1);
    if (! found) {
	setmsg_("The variable, '#', specifying the boresight of the instrume"
		"nt # was not found in the kernel pool. Check whether IK file"
		" for the instrument was loaded into the program and whether "
		"this variable is specified in that file.", (ftnlen)219);
	errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	errint_("#", instid, (ftnlen)1);
	sigerr_("SPICE(BORESIGHTMISSING)", (ftnlen)23);
	chkout_("GETFOV", (ftnlen)6);
	return 0;
    }

/*     Check whether boresight specified by three coordinates; */
/*     complain if not. */

    if (i__ != 3) {
	setmsg_("The number of the boresight vector components specified in "
		"the '#' variable is not 3, it is #. Correct it in the corres"
		"ponding IK file to be a 3-dimensional vector. ", (ftnlen)165);
	errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	errint_("#", &i__, (ftnlen)1);
	sigerr_("SPICE(BADBORESIGHTSPEC)", (ftnlen)23);
	chkout_("GETFOV", (ftnlen)6);
	return 0;
    } else if (*(unsigned char *)type__ != 'N') {
	setmsg_("The boresight vector, stored in the '#' variable, has not b"
		"een stored as a vector of three numbers.  It has been stored"
		" as a vector of three strings. ", (ftnlen)150);
	errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	sigerr_("SPICE(BADBORESIGHTSPEC)", (ftnlen)23);
	chkout_("GETFOV", (ftnlen)6);
	return 0;
    }
    gdpool_(kword, &c__1, &c__3, &i__, bsight, &found, (ftnlen)32);

/*     At this point we have gotten all the specification independent */
/*     information.  Now check for the presence of the FOV class */
/*     specification keyword.  If it's absent, we default to CORNERS. */

    s_copy(spec, "CORNERS", (ftnlen)80, (ftnlen)7);
    repmi_(kwspec, "#", instid, kword, (ftnlen)32, (ftnlen)1, (ftnlen)32);
    gcpool_(kword, &c__1, &c__1, &i__, spec, &found, (ftnlen)32, (ftnlen)80);
    if (eqstr_("CORNERS", spec, (ftnlen)7, (ftnlen)80)) {

/*        Look for the FOV boundary vectors, check whether output array */
/*        is big enough to hold them; complain if not. */

	repmi_(kwboun, "#", instid, kword, (ftnlen)32, (ftnlen)1, (ftnlen)32);
	dtpool_(kword, &found, n, type__, (ftnlen)32, (ftnlen)1);
	if (! found) {
	    suffix_("_CORNERS", &c__0, kword, (ftnlen)8, (ftnlen)32);
	    dtpool_(kword, &found, n, type__, (ftnlen)32, (ftnlen)1);
	}
	if (! found) {
	    repmi_(kwboun, "#", instid, kword, (ftnlen)32, (ftnlen)1, (ftnlen)
		    32);
	    setmsg_("The variable, '#', specifying the boundary vectors of t"
		    "he instrument # FOV was not found in the kernel pool. Ch"
		    "eck whether IK file for the instrument was loaded into t"
		    "he program and whether this variable is specified in tha"
		    "t file.", (ftnlen)230);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    errint_("#", instid, (ftnlen)1);
	    sigerr_("SPICE(BOUNDARYMISSING)", (ftnlen)22);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	}

/*        Check whether we have enough room to get all boundary vectors, */
/*        complain if not. */

	if (*n > mxcmp) {
	    setmsg_("The number of boundary vector components specified in t"
		    "he '#' pool variable is bigger than room to hold them in"
		    " output array specified by the ROOM input variable of th"
		    "e GETFOV subroutine.", (ftnlen)187);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    sigerr_("SPICE(BOUNDARYTOOBIG)", (ftnlen)21);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	}

/*        Check whether number of boundary components can be divided by 3 */
/*        without reminder. */

	if (*n % 3 != 0) {
	    setmsg_("The boundary vector components specified in the '#' poo"
		    "l variable do  not represent a set of 3-dimensional vect"
		    "ors. Number of components assigned to the variable canno"
		    "t be divided by 3 without reminder. ", (ftnlen)203);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    sigerr_("SPICE(BADBOUNDARY)", (ftnlen)18);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	}

/*        Boundaries are OK. Get them. */

	gdpool_(kword, &c__1, &mxcmp, n, bounds, &found, (ftnlen)32);
	*n /= 3;
	if (s_cmp(shape, "CIRCLE", shape_len, (ftnlen)6) == 0 && *n != 1) {
	    setmsg_("The boundary is specified to be circular, and as such, "
		    "the values associated with keyword, '#', should contain "
		    "one vector.  There are #.", (ftnlen)136);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    errint_("#", n, (ftnlen)1);
	    sigerr_("SPICE(BADBOUNDARY)", (ftnlen)18);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	} else if (s_cmp(shape, "ELLIPSE", shape_len, (ftnlen)7) == 0 && *n !=
		 2) {
	    setmsg_("The boundary is specified to be elliptical, and as such"
		    ", the values associated with keyword, '#', should contai"
		    "n two vectors.  There are #.", (ftnlen)139);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    errint_("#", n, (ftnlen)1);
	    sigerr_("SPICE(BADBOUNDARY)", (ftnlen)18);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	} else if (s_cmp(shape, "RECTANGLE", shape_len, (ftnlen)9) == 0 && *n 
		!= 4) {
	    setmsg_("The boundary is specified to be rectangular, and as suc"
		    "h, the values associated with keyword, '#', should conta"
		    "in four vectors.  There are #.", (ftnlen)141);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    errint_("#", n, (ftnlen)1);
	    sigerr_("SPICE(BADBOUNDARY)", (ftnlen)18);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	} else if (s_cmp(shape, "POLYGON", shape_len, (ftnlen)7) == 0 && *n < 
		3) {
	    setmsg_("The boundary is specified to be polygonal, and as such,"
		    " the values associated with keyword, '#', should contain"
		    " at least three vectors.  There are #.", (ftnlen)149);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    errint_("#", n, (ftnlen)1);
	    sigerr_("SPICE(BADBOUNDARY)", (ftnlen)18);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	}

/*     Now check to see if the FOV specification is ANGLES and */
/*     compute the boundary corner vectors. */

    } else if (eqstr_("ANGLES", spec, (ftnlen)6, (ftnlen)80)) {

/*        Check whether shape identified that we got is one from the list */
/*        of supported shapes for the ANGLE specification; complain */
/*        if not. */

	if (bsrchc_(shape, &c__3, angshp, rtrim_(shape, shape_len), (ftnlen)
		32) == 0) {
	    setmsg_("The FOV shape, '#', specified in the keyword, '#', for "
		    "the instrument # is not supported for the ANGLES specifi"
		    "cation.", (ftnlen)118);
	    errch_("#", shape, (ftnlen)1, rtrim_(shape, shape_len));
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    errint_("#", instid, (ftnlen)1);
	    sigerr_("SPICE(SHAPENOTSUPPORTED)", (ftnlen)24);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	}

/*        Now fetch all of the elements independent of shape from the */
/*        ANGLES specification.  Start by looking for the reference */
/*        vector keyword.  If found, fetch it otherwise complain. */

	repmi_(kwrvec, "#", instid, kword, (ftnlen)32, (ftnlen)1, (ftnlen)32);
	dtpool_(kword, &found, &i__, type__, (ftnlen)32, (ftnlen)1);
	if (! found) {
	    setmsg_("The variable, '#', specifying the FOV reference vector "
		    "of the instrument # was not found in the kernel pool. Ch"
		    "eck whether IK file for the instrument was loaded into t"
		    "he program and whether this variable is specified in tha"
		    "t file.", (ftnlen)230);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    errint_("#", instid, (ftnlen)1);
	    sigerr_("SPICE(REFVECTORMISSING)", (ftnlen)23);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	}

/*        Now check whether reference vector is specified by three */
/*        coordinates; complain if not. */

	if (i__ != 3) {
	    setmsg_("The number of the reference vector components specified"
		    " in the '#' keyword is not 3, it is #. Check the corresp"
		    "onding IK FOV definition for errors.", (ftnlen)147);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    errint_("#", &i__, (ftnlen)1);
	    sigerr_("SPICE(BADREFVECTORSPEC)", (ftnlen)23);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	} else if (*(unsigned char *)type__ != 'N') {
	    setmsg_("The reference vector, stored in '#', has not been store"
		    "d as a vector of three numbers.  It has been stored as a"
		    " vector of three strings. ", (ftnlen)137);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    sigerr_("SPICE(BADREFVECTORSPEC)", (ftnlen)23);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	}
	gdpool_(kword, &c__1, &c__3, &i__, refvec, &found, (ftnlen)32);

/*        We require that the reference vector is not parallel */
/*        to the boresight vector. Use NORMAL(1,1) to temporarily */
/*        store the result of the cross product. */

	vcrss_(bsight, refvec, normal);
	if (vnorm_(normal) == 0.) {
	    setmsg_("The reference vector, stored in '#', is parallel to the"
		    " instrument boresight vector.  This is not allowed by th"
		    "e ANGLES FOV specification.", (ftnlen)138);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    sigerr_("SPICE(BADREFVECTORSPEC)", (ftnlen)23);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	}

/*        Retrieve the reference angle from the kernel pool. */

	repmi_(kwrang, "#", instid, kword, (ftnlen)32, (ftnlen)1, (ftnlen)32);
	gdpool_(kword, &c__1, &c__1, &i__, &refang, &found, (ftnlen)32);
	if (! found) {
	    setmsg_("The variable, '#', specifying the reference angle which"
		    " describes instrument # FOV angular extent was not found"
		    " in the kernel pool. Check whether IK file for the instr"
		    "ument was loaded into the program and whether this varia"
		    "ble is specified in that file.", (ftnlen)253);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    errint_("#", instid, (ftnlen)1);
	    sigerr_("SPICE(REFANGLEMISSING)", (ftnlen)22);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	}

/*        Retrieve the angle units from the kernel pool. */

	repmi_(kwaunt, "#", instid, kword, (ftnlen)32, (ftnlen)1, (ftnlen)32);
	gcpool_(kword, &c__1, &c__1, &i__, angunt, &found, (ftnlen)32, (
		ftnlen)80);
	if (! found) {
	    setmsg_("The variable, '#', specifying the angular units in whic"
		    "h instrument # FOV extent is defined was not found in th"
		    "e kernel pool. Check whether IK file for the instrument "
		    "was loaded into the program and whether this variable is"
		    " specified in that file.", (ftnlen)247);
	    errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
	    errint_("#", instid, (ftnlen)1);
	    sigerr_("SPICE(UNITSMISSING)", (ftnlen)19);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	}

/*        Convert the reference angle to radians. */

	convrt_(&refang, angunt, "RADIANS", &tmpang, (ftnlen)80, (ftnlen)7);
	refang = tmpang;

/*        Branch to shape specific code. */

	if (s_cmp(shape, "CIRCLE", shape_len, (ftnlen)6) == 0) {

/*           First check to see that the caller left enough room */
/*           to store the required number of boundary corner */
/*           vectors. */

	    if (*room < 1) {
		setmsg_("The FOV shape for instrument # is specified to be c"
			"ircular.  There should be room for at least one boun"
			"dary vector.  There is room for #. ", (ftnlen)138);
		errint_("#", instid, (ftnlen)1);
		errint_("#", room, (ftnlen)1);
		sigerr_("SPICE(BOUNDARYTOOBIG)", (ftnlen)21);
		chkout_("GETFOV", (ftnlen)6);
		return 0;
	    }

/*           The plan to compute the boundary corner vector is to */
/*           rotate the BSIGHT by REFANG towards REFVEC.  To do */
/*           this first compute the axis we need to rotate about. */

	    vcrss_(bsight, refvec, normal);

/*           Now rotate by REFANG about NORMAL(1,1) using the routine */
/*           VROTV. */

	    vrotv_(bsight, normal, &refang, bounds);

/*           Lastly, since we computed a single boundary corner vector, */
/*           set N = 1. */

	    *n = 1;
	} else if (s_cmp(shape, "ELLIPSE", shape_len, (ftnlen)7) == 0) {

/*           The elliptical case requires the additional cross angle */
/*           keyword's presence in the kernel pool. Attempt to */
/*           retrieve it. */

	    repmi_(kwcang, "#", instid, kword, (ftnlen)32, (ftnlen)1, (ftnlen)
		    32);
	    gdpool_(kword, &c__1, &c__1, &i__, &crsang, &found, (ftnlen)32);
	    if (! found) {
		setmsg_("The variable, '#', specifying the cross angle which"
			" describes instrument # FOV angular extent was not f"
			"ound in the kernel pool. Check whether IK file for t"
			"he instrument was loaded into the program and whethe"
			"r this variable is specified in that file.", (ftnlen)
			249);
		errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
		errint_("#", instid, (ftnlen)1);
		sigerr_("SPICE(CROSSANGLEMISSING)", (ftnlen)24);
		chkout_("GETFOV", (ftnlen)6);
		return 0;
	    }

/*           Convert the cross angle to radians. */

	    convrt_(&crsang, angunt, "RADIANS", &tmpang, (ftnlen)80, (ftnlen)
		    7);
	    crsang = tmpang;

/*           Now check to see that the caller left enough room */
/*           to store the required number of boundary corner */
/*           vectors. */

	    if (*room < 2) {
		setmsg_("The FOV shape for instrument # is specified to be e"
			"lliptical.  There should be room for at least two bo"
			"undary vectors.  There is room for #. ", (ftnlen)141);
		errint_("#", instid, (ftnlen)1);
		errint_("#", room, (ftnlen)1);
		sigerr_("SPICE(BOUNDARYTOOBIG)", (ftnlen)21);
		chkout_("GETFOV", (ftnlen)6);
		return 0;
	    }

/*           The plan to compute the first boundary corner vector is */
/*           to rotate the BSIGHT by REFANG towards REFVEC.  To */
/*           do this first compute the axis we need to rotate about. */

	    vcrss_(bsight, refvec, normal);

/*           Now rotate by REFANG about NORMAL(1,1) using the routine */
/*           VROTV. */

	    vrotv_(bsight, normal, &refang, bounds);

/*           At this point we have one boundary vector.  We need the */
/*           second and final one.  The strategy we will use is the */
/*           following: rotate BSIGHT by CRSANG towards NORMAL(1,1). */
/*           This will give us boundary corner vectors listed in a */
/*           counter-clockwise fashion about the boresight. */

	    vcrss_(bsight, normal, tmpvec);
	    vequ_(tmpvec, &normal[3]);

/*           Now rotate BSIGHT by CRSANG about the NORMAL(1,2) using */
/*           the routine VROTV. */

	    vrotv_(bsight, &normal[3], &crsang, &bounds[3]);

/*           Lastly, since we computed two boundary corner vectors, */
/*           set N = 2. */

	    *n = 2;
	} else if (s_cmp(shape, "RECTANGLE", shape_len, (ftnlen)9) == 0) {

/*           The rectangular case requires the additional cross angle */
/*           keyword's presence in the kernel pool. Attempt to */
/*           retrieve it. */

	    repmi_(kwcang, "#", instid, kword, (ftnlen)32, (ftnlen)1, (ftnlen)
		    32);
	    gdpool_(kword, &c__1, &c__1, &i__, &crsang, &found, (ftnlen)32);
	    if (! found) {
		setmsg_("The variable, '#', specifying the cross angle which"
			" describes instrument # FOV angular extent was not f"
			"ound in the kernel pool. Check whether IK file for t"
			"he instrument was loaded into the program and whethe"
			"r this variable is specified in that file.", (ftnlen)
			249);
		errch_("#", kword, (ftnlen)1, rtrim_(kword, (ftnlen)32));
		errint_("#", instid, (ftnlen)1);
		sigerr_("SPICE(CROSSANGLEMISSING)", (ftnlen)24);
		chkout_("GETFOV", (ftnlen)6);
		return 0;
	    }

/*           Convert the cross angle to radians. */

	    convrt_(&crsang, angunt, "RADIANS", &tmpang, (ftnlen)80, (ftnlen)
		    7);
	    crsang = tmpang;

/*           Now check to see that the caller left enough room */
/*           to store the required number of boundary corner */
/*           vectors. */

	    if (*room < 4) {
		setmsg_("The FOV shape for instrument # is specified to be r"
			"ectangular.  There should be room for at least four "
			"boundary vectors.  There is room for #. ", (ftnlen)
			143);
		errint_("#", instid, (ftnlen)1);
		errint_("#", room, (ftnlen)1);
		sigerr_("SPICE(BOUNDARYTOOBIG)", (ftnlen)21);
		chkout_("GETFOV", (ftnlen)6);
		return 0;
	    }

/*           Here's the general strategy laid out in simple terms: */

/*           (1) Normalize BSIGHT, label it B. */

/*           (2) Compute the unit vector in the plane defined by REFVEC */
/*               and B that is normal to B and pointing towards */
/*               REFVEC, label this B1. */

/*           (3) Cross B and B1 to obtain B2. These three vectors */
/*               form a basis that is 'aligned' with the FOV cone. */

/*           (4) Compute the inward normals to the sides of the */
/*               rectangular cone in a counter-clockwise order */
/*               about the boresight: */

/*                 NORMAL(1) = -COS(REFANG)*B1 + SIN(REFANG)*B */
/*                 NORMAL(2) = -COS(CRSANG)*B2 + SIN(CRSANG)*B */
/*                 NORMAL(3) =  COS(REFANG)*B1 + SIN(REFANG)*B */
/*                 NORMAL(4) =  COS(CRSANG)*B2 + SIN(CRSANG)*B */

/*           (5) Compute the appropriate cross products to obtain */
/*               a set of boundary corner vectors: */

/*                 BOUNDS(1) = NORMAL(1) x NORMAL(2) */
/*                 BOUNDS(2) = NORMAL(2) x NORMAL(3) */
/*                 BOUNDS(3) = NORMAL(3) x NORMAL(4) */
/*                 BOUNDS(4) = NORMAL(4) x NORMAL(1) */

/*           (6) Unitize and scale BOUNDS to match the length */
/*               of the BSIGHT. */

/*           Start with step (1). */

	    unorm_(bsight, b, &bmag);

/*           Now proceed to (2). Since we already know that REFVEC */
/*           and BSIGHT are not parallel, the following yields a */
/*           non-zero vector: */

	    vperp_(refvec, bsight, b1);

/*           Unitize B1. */

	    vhat_(b1, tmpvec);
	    vequ_(tmpvec, b1);

/*           Step (3), compute B2 by crossing B and B1. */

	    vcrss_(b, b1, b2);

/*           Before proceeding onto step (4), verify that the */
/*           results of the calculations in step (4) will make */
/*           sense.  Check the cosines of CRSANG and REFANG. */
/*           Signal an error if both are not positive numbers. */
/*           Use MINCOS as a tolerance. */

	    cosran = cos(refang);
	    coscan = cos(crsang);
	    if (cosran < 1e-15 || coscan < 1e-15) {
		setmsg_("The angular extents specified in the FOV definition"
			" for instrument # result in degenerate or improper b"
			"oundary corner vectors.  This usually is the case wh"
			"en one or both of the angles specified is 90 degrees."
			, (ftnlen)208);
		errint_("#", instid, (ftnlen)1);
		sigerr_("SPICE(BADBOUNDARY)", (ftnlen)18);
		chkout_("GETFOV", (ftnlen)6);
		return 0;
	    }

/*           Compute the NORMAL vectors to complete step (4). */

	    sinran = sin(refang);
	    sincan = sin(crsang);
	    d__1 = -cosran;
	    vlcom_(&d__1, b1, &sinran, b, normal);
	    d__1 = -coscan;
	    vlcom_(&d__1, b2, &sincan, b, &normal[3]);
	    vlcom_(&cosran, b1, &sinran, b, &normal[6]);
	    vlcom_(&coscan, b2, &sincan, b, &normal[9]);

/*           We are almost finished. Compute the boundary corner */
/*           vectors completing step (5). */

	    vcrss_(normal, &normal[3], bounds);
	    vcrss_(&normal[3], &normal[6], &bounds[3]);
	    vcrss_(&normal[6], &normal[9], &bounds[6]);
	    vcrss_(&normal[9], normal, &bounds[9]);

/*           Step (6), normalize the boundary corner vectors */
/*           and scale by BMAG, the magnitude of BSIGHT. */

	    for (i__ = 1; i__ <= 4; ++i__) {
		unorm_(&bounds[i__ * 3 - 3], tmpvec, &vmag);
		vscl_(&bmag, tmpvec, &bounds[i__ * 3 - 3]);
	    }

/*           Lastly since we are returning 4 boundary corner vectors, */
/*           set N = 4. */

	    *n = 4;
	} else {

/*           If we end up here something is terribly wrong with */
/*           this module or SPICE in general. */

	    setmsg_("This error is never supposed to occur. We have an undef"
		    "ined shape for the ANGLES specification that passed the "
		    "shape check.", (ftnlen)123);
	    sigerr_("SPICE(BUG)", (ftnlen)10);
	    chkout_("GETFOV", (ftnlen)6);
	    return 0;
	}
    } else {
	setmsg_("The FOV class specification is set to '#' which is currentl"
		"y unsupported. See the GETFOV subroutine header for more inf"
		"ormation.", (ftnlen)128);
	errch_("#", spec, (ftnlen)1, (ftnlen)80);
	sigerr_("SPICE(UNSUPPORTEDSPEC)", (ftnlen)22);
	chkout_("GETFOV", (ftnlen)6);
	return 0;
    }

/*     Standard SPICE error handling. */

    chkout_("GETFOV", (ftnlen)6);
    return 0;
} /* getfov_ */

