NGRITD(3NCARG) NCAR GRAPHICS NGRITD(3NCARG)

# 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¶

(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).
(an input expression of type REAL) specifies the magnitude, in degrees, of the rotation angle.
(an input/output variable of type REAL) specifies the U coordinate of the point being rotated.
(an input/output variable of type REAL) specifies the V coordinate of the point being rotated.
(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.

None.