NAME

       SRFACE - Draws a perspective picture of a function of two variables with hidden lines
       removed. The function is approximated by a two-dimensional array of heights.

SYNOPSIS

       CALL SRFACE (X,Y,Z,M,MX,NX,NY,S,STEREO)

C-BINDING SYNOPSIS

       #include <ncarg/ncargC.h>

       void c_srface (float *x, float *y, float *z, int *m,
       int mx, int nx, int ny, float s[6], float stereo)

DESCRIPTION

       X           A linear array NX long containing the X coordinates of the points in the
                   surface approximation.  See "USAGE" below.

       Y           The linear array NY long containing the Y coordinates of the points in the
                   surface approximation.  See "USAGE" below.

       Z           An array MX by NY containing the surface to be drawn in NX by NY cells. Z(I,J)
                   = F(X(I),Y(J)).  See "USAGE" below.

       M           Scratch array at least 2*NX*NY words long.

       MX          First dimension of Z.

       NX          Number of data values in the X direction (the first subscript direction) in Z
                   to be plotted.  When plotting an entire array, MX=NX.

       NY          Number of data values in the Y direction (the second subscript direction) to
                   be plotted.

       S           S defines the line of sight. The viewer's eye is at (S(1), S(2), S(3)) and the
                   point looked at is at (S(4), S(5), S(6)). The eye should be outside the block
                   with opposite corners (X(1), Y(1), ZMIN) and (X(NX), Y(NY), ZMAX) and the
                   point looked at should be inside it. For a nice perspective effect, the
                   distance between the eye and the point looked at should be 5 to 10 times the
                   size of the block.

       STEREO      Flag to indicate if stereo pairs are to be drawn.  0.0 means no stereo pair
                   (one picture). Non-zero means put out two pictures. The value of STEREO is the
                   relative angle between the eyes. A value of 1.0 produces standard separation.
                   Negative STEREO reverses the left and right figures.

C-BINDING DESCRIPTION

       The C-binding argument descriptions are the same as the FORTRAN argument descriptions,
       with the following exceptions:

       z           An array ny by mx.

       mx          Second dimension of z.

       nx          Number of data values in the y direction (the second subscript direction) in z
                   to be plotted.  When plotting an entire array, mx=nx.

       ny          Number of data values in the x direction (the first subscript direction) to be
                   plotted.

USAGE

       • The range of Z compared with the range of X and Y determines the shape of the picture.
         They are assumed to be in the same units and not wildly different in magnitude. S is
         assumed to be in the same units as X, Y, and Z.

       • Picture size can be made relative to distance.

       • TRN32S can be used to translate from 3 space to 2 space.

       • Data with extreme discontinuities may cause visibility errors. If this problem occurs,
         use a distant eye position away from the +Z axis.

       • The default line color is set to color index 1. If the user wishes to change the line
         color, he can do so by defining color index 1 before calling SRFACE, or by putting the
         common block SRFINT in his calling program and defining and using color index ISRFMJ
         (defaulted to 1 in BLOCKDATA).

EXAMPLES

       Use the ncargex command to see the following relevant examples: srex01, tpwrzs, tsrfac,
       fsrpwrzs, fsrsrfac.

ACCESS

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

SEE ALSO

       Online: surface, surface_params, ezsrfc, pwrzs, setr, ncarg_cbind.

       Hardcopy: NCAR Graphics Fundamentals, UNIX Version

COPYRIGHT

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