1Bivar(3NCARG)                    NCAR GRAPHICS                   Bivar(3NCARG)
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NAME

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

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

34       c_idbvip,
35       c_idsfft
36       c_idpltr
37       c_idgeti
38       c_idgetr
39       c_idseti
40       c_idsetr
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EXAMPLES

43       See the example "cbex01".
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ACCESS

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

51       When error conditions are detected, the support routine SETER is
52       called. By default, SETER writes a message to the standard error file
53       (as defined by I1MACH(4)) and then terminates execution.  It is
54       possible to put SETER into recovery mode and regain control after a
55       recoverable error (which includes all of the possible errors).
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57       The possible error messages are listed below.  All errors are
58       recoverable in the sense that a user program which has called ENTSR to
59       set recovery mode will get control back after one of these errors
60       occurs.
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62       IDBVIP (BIVAR) - UNCLEARED PRIOR ERROR
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64       IDBVIP (BIVAR) - INPUT VARIABLE MD IS OUT OF RANGE
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66       IDBVIP (BIVAR) - INPUT VARIABLE NDP IS OUT OF RANGE
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68       IDBVIP (BIVAR) - INPUT VARIABLE NIP IS OUT OF RANGE
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70       IDBVIP (BIVAR) - MD = 2 OR 3 BUT NDP WAS CHANGED SINCE LAST CALL
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72       IDBVIP (BIVAR) - MD = 3 BUT ITY WAS CHANGED SINCE LAST CALL
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74       IDBVIP (BIVAR) - MD = 3 BUT NIP WAS CHANGED SINCE LAST CALL
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76       IDGETI (BIVAR) - UNCLEARED PRIOR ERROR
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78       IDGETR (BIVAR) - UNCLEARED PRIOR ERROR
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80       IDGETR (BIVAR) - INVALID KEYWORD: xxx
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82       IDGRID (BIVAR) - INTERNAL ERROR - SEE CONSULTANT
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84       IDPLTR (BIVAR) - UNCLEARED PRIOR ERROR
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86       IDSETI (BIVAR) - UNCLEARED PRIOR ERROR
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88       IDSETR (BIVAR) - UNCLEARED PRIOR ERROR
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90       IDSETR (BIVAR) - INVALID KEYWORD: xxx
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92       IDSFFT (BIVAR) - UNCLEARED PRIOR ERROR
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94       IDSFFT (BIVAR) - INPUT VARIABLE MD IS OUT OF RANGE
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96       IDSFFT (BIVAR) - INPUT VARIABLE NDP IS OUT OF RANGE
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98       IDSFFT (BIVAR) - INPUT VARIABLE NXI OR NYI IS OUT OF RANGE
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100       IDSFFT (BIVAR) - INPUT VARIABLE NZI IS LESS THAN NXI
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102       IDSFFT (BIVAR) - MD = 2 OR 3 BUT NDP WAS CHANGED SINCE LAST CALL
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104       IDSFFT (BIVAR) - MD = 3 BUT ITY WAS CHANGED SINCE LAST CALL
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106       IDSFFT (BIVAR) - MD = 3 BUT NXI WAS CHANGED SINCE LAST CALL
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108       IDSFFT (BIVAR) - MD = 3 BUT NYI WAS CHANGED SINCE LAST CALL
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110       IDTANG (BIVAR) - INPUT PARAMETER NDP OUT OF RANGE
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112       IDTANG (BIVAR) - TWO OF THE INPUT DATA POINTS ARE IDENTICAL
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114       IDTANG (BIVAR) - ALL COLLINEAR DATA POINTS
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SEE ALSO

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

124       Bivar was written by Hiroshi Akima in August 1975 and rewritten by him
125       in late 1976.  In 1989, a new version of Bivar, incorporating changes
126       described in a Rocky Mountain Journal of Mathematics was obtained from
127       Dr. Akima, and included in NCAR Graphics with his permission.  In 1995,
128       Dave Kennison incorporated the capability of doing linear interpolation
129       and a different kind of triangulation, put in a parameter access
130       interface, and wrote a routine to allow the triangulation to be
131       plotted.
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134       Copyright (C) 1987-2009
135       University Corporation for Atmospheric Research
136       The use of this Software is governed by a License Agreement.
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140UNIX                             November 1995                   Bivar(3NCARG)
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