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Bivar(3NCARG) NCAR GRAPHICS Bivar(3NCARG)

NAME

Bivar - Provides bivariate interpolation and smooth surface fitting for values given at irregularly distributed points. The resulting interpolating function and its first-order partial derivatives are continuous. The method employed is local, i.e. a change in the data in one area of the plane does not affect the interpolating function except in that local area. Also, the method gives exact results when all points lie in a plane.

SYNOPSIS

IDBVIP
Produces interpolated values at points (XI(I), YI(I)), I=1,...,NIP. This is useful for filling in missing data points on a grid.
IDSFFT
Performs smooth surface fitting when the projections of the data points in the X-Y plane are irregularly distributed in the plane.
IDPLTR
Plots the triangulation of the data points.
IDGETI
Retrieves the integer value of a Bivar parameter.
IDGETR
Retrieves the real value of a Bivar parameter.
IDSETI
Provides a new integer value for a Bivar parameter.
IDSETR
Provides a new real value for a Bivar parameter.

C-BINDING SYNOPSIS

c_idbvip,
 
c_idsfft
 
c_idpltr
 
c_idgeti
 
c_idgetr
 
c_idseti
 
c_idsetr

EXAMPLES

See the example "cbex01".

ACCESS

To use the Bivar Fortran or C routines, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably in that order.

MESSAGES

When error conditions are detected, the support routine SETER is called. By default, SETER writes a message to the standard error file (as defined by I1MACH(4)) and then terminates execution. It is possible to put SETER into recovery mode and regain control after a recoverable error (which includes all of the possible errors).
The possible error messages are listed below. All errors are recoverable in the sense that a user program which has called ENTSR to set recovery mode will get control back after one of these errors occurs.
IDBVIP (BIVAR) - UNCLEARED PRIOR ERROR
IDBVIP (BIVAR) - INPUT VARIABLE MD IS OUT OF RANGE
IDBVIP (BIVAR) - INPUT VARIABLE NDP IS OUT OF RANGE
IDBVIP (BIVAR) - INPUT VARIABLE NIP IS OUT OF RANGE
IDBVIP (BIVAR) - MD = 2 OR 3 BUT NDP WAS CHANGED SINCE LAST CALL
IDBVIP (BIVAR) - MD = 3 BUT ITY WAS CHANGED SINCE LAST CALL
IDBVIP (BIVAR) - MD = 3 BUT NIP WAS CHANGED SINCE LAST CALL
IDGETI (BIVAR) - UNCLEARED PRIOR ERROR
IDGETR (BIVAR) - UNCLEARED PRIOR ERROR
IDGETR (BIVAR) - INVALID KEYWORD: xxx
IDGRID (BIVAR) - INTERNAL ERROR - SEE CONSULTANT
IDPLTR (BIVAR) - UNCLEARED PRIOR ERROR
IDSETI (BIVAR) - UNCLEARED PRIOR ERROR
IDSETR (BIVAR) - UNCLEARED PRIOR ERROR
IDSETR (BIVAR) - INVALID KEYWORD: xxx
IDSFFT (BIVAR) - UNCLEARED PRIOR ERROR
IDSFFT (BIVAR) - INPUT VARIABLE MD IS OUT OF RANGE
IDSFFT (BIVAR) - INPUT VARIABLE NDP IS OUT OF RANGE
IDSFFT (BIVAR) - INPUT VARIABLE NXI OR NYI IS OUT OF RANGE
IDSFFT (BIVAR) - INPUT VARIABLE NZI IS LESS THAN NXI
IDSFFT (BIVAR) - MD = 2 OR 3 BUT NDP WAS CHANGED SINCE LAST CALL
IDSFFT (BIVAR) - MD = 3 BUT ITY WAS CHANGED SINCE LAST CALL
IDSFFT (BIVAR) - MD = 3 BUT NXI WAS CHANGED SINCE LAST CALL
IDSFFT (BIVAR) - MD = 3 BUT NYI WAS CHANGED SINCE LAST CALL
IDTANG (BIVAR) - INPUT PARAMETER NDP OUT OF RANGE
IDTANG (BIVAR) - TWO OF THE INPUT DATA POINTS ARE IDENTICAL
IDTANG (BIVAR) - ALL COLLINEAR DATA POINTS

SEE ALSO

Online: bivar_params, idbvip, idsfft, idpltr, idgeti, idgetr, idseti, idsetr, ncarg_cbind
Hardcopy: NCAR Graphics Contouring and Mapping Tutorial; NCAR Graphics Fundamentals, UNIX Version

ACKNOWLEDGMENTS

Bivar was written by Hiroshi Akima in August 1975 and rewritten by him in late 1976. In 1989, a new version of Bivar, incorporating changes described in a Rocky Mountain Journal of Mathematics was obtained from Dr. Akima, and included in NCAR Graphics with his permission. In 1995, Dave Kennison incorporated the capability of doing linear interpolation and a different kind of triangulation, put in a parameter access interface, and wrote a routine to allow the triangulation to be plotted.

COPYRIGHT

Copyright (C) 1987-2009
 
University Corporation for Atmospheric Research
 
The use of this Software is governed by a License Agreement.
November 1995 UNIX