NAME

       plvect - Vector plot

SYNOPSIS

       plvect(u, v, nx, ny, scale, pltr, pltr_data)

DESCRIPTION

       Draws  a plot of vector data contained in the matrices (u[nx][ny],v[nx][ny]) . The scaling
       factor for the vectors is given by scale. A transformation routine pointed to by pltr with
       a  pointer  pltr_data  for  additional  data required by the transformation routine to map
       indices within the matrices to the world coordinates. The style of the vector arrow may be
       set using plsvect(3plplot).

       Redacted form: plvect(u, v, scale, pltr, pltr_data) where (see above discussion) the pltr,
       pltr_data callback arguments are sometimes replaced by a tr vector with 6 elements, or  xg
       and yg array arguments with either one or two dimensions.

       This function is used in example 22.

ARGUMENTS

       u, v (PLFLT_MATRIX(3plplot), input)
              A  pair  of  matrices  containing  the  x and y components of the vector data to be
              plotted.

       nx, ny (PLINT(3plplot), input)
              Dimensions of the matrices u and v.

       scale (PLFLT(3plplot), input)
              Parameter to control the scaling factor of the vectors for plotting. If scale  =  0
              then the scaling factor is automatically calculated for the data. If scale < 0 then
              the scaling factor is automatically calculated for the data and then multiplied  by
              -scale. If scale > 0 then the scaling factor is set to scale.

       pltr (PLTRANSFORM_callback(3plplot), input)
              A  callback function that defines the transformation between the zero-based indices
              of the matrices u and v  and  world  coordinates.For  the  C  case,  transformation
              functions  are  provided  in  the  PLplot  library: pltr0(3plplot) for the identity
              mapping, and pltr1(3plplot) and pltr2(3plplot) for arbitrary mappings  respectively
              defined  by  vectors  and  matrices.   In  addition,  C  callback  routines for the
              transformation can be  supplied  by  the  user  such  as  the  mypltr  function  in
              examples/c/x09c.c  which  provides  a  general  linear transformation between index
              coordinates and world coordinates.For languages other than C you should consult the
              PLplot  documentation  for the details concerning how PLTRANSFORM_callback(3plplot)
              arguments are interfaced. However, in general, a particular  pattern  of  callback-
              associated  arguments such as a tr vector with 6 elements; xg and yg vectors; or xg
              and yg matrices are respectively  interfaced  to  a  linear-transformation  routine
              similar   to   the  above  mypltr  function;  pltr1(3plplot);  and  pltr2(3plplot).
              Furthermore, some of  our  more  sophisticated  bindings  (see,  e.g.,  the  PLplot
              documentation)  support  native  language  callbacks  for  handling index to world-
              coordinate transformations.  Examples of these  various  approaches  are  given  in
              examples/<language>x09*,      examples/<language>x16*,     examples/<language>x20*,
              examples/<language>x21*,  and  examples/<language>x22*,  for  all   our   supported
              languages.

       pltr_data (PLPointer(3plplot), input)
              Extra  parameter  to  help  pass  information  to  pltr0(3plplot),  pltr1(3plplot),
              pltr2(3plplot), or whatever callback routine that is externally supplied.

AUTHORS

       Many developers  (who  are  credited  at  http://plplot.sourceforge.net/credits.php)  have
       contributed to PLplot over its long history.

SEE ALSO

       PLplot documentation at http://plplot.sourceforge.net/documentation.php.

                                          November, 2017                          PLVECT(3plplot)