NAME

       NGRITD - Given the coordinates of a point, this routine performs a rotation of that point
       about a specified axis by a specified angle.

SYNOPSIS

       CALL NGRITD (IAXS,ANGL,UCRD,VCRD,WCRD)

C-BINDING SYNOPSIS

       #include <ncarg/ncargC.h>

       void c_ngritd(int iaxs, float angl, float *ucrd, float *ycrd,
       float *wcrd)

DESCRIPTION

       IAXS        (an input expression of type INTEGER) specifies the axis about which rotation
                   is to be done (1 for the U axis, 2 for the V axis, and 3 for the W axis).

       ANGL        (an input expression of type REAL) specifies the magnitude, in degrees, of the
                   rotation angle.

       UCRD        (an input/output variable of type REAL) specifies the U coordinate of the
                   point being rotated.

       VCRD        (an input/output variable of type REAL) specifies the V coordinate of the
                   point being rotated.

       WCRD        (an input/output variable of type REAL) specifies the W coordinate of the
                   point being rotated.

C-BINDING DESCRIPTION

       The C binding argument descriptions are the same as the FORTRAN argument descriptions.

USAGE

       This routine is used by NGGCOG and NGGSOG to effect the rotations that are used to
       generate an object of a specified shape at a specified point on the surface of the globe.

       NGRITD assumes that the UVW coordinate system is right-handed.  Positive values of ANGL
       give counter-clockwise rotations and negative values of ANGL give clockwise rotations.
       (When IAXS = 1, ANGL = 90 carries the positive V axis into the positive W axis; when IAXS
       = 2, ANGL = 90 carries the positive W axis into the positive U axis; when IAXS = 3, ANGL =
       90 carries the positive U axis into the positive V axis.)

EXAMPLES

       Use the ncargex command to see the following relevant example: cpex10.

ACCESS

       To use NGRITD or c_ngritd, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c,
       preferably in that order.

MESSAGES

       None.

SEE ALSO

       Online: nggcog(3NCARG), nggsog(3NCARG).

COPYRIGHT

       Copyright (C) 1987-2009
       University Corporation for Atmospheric Research
       The use of this Software is governed by a License Agreement.