Re: [Gnuplot-info] Vector fields with pseudo-file '+'

[Peter D. <pc...@wi...>]

On Thu, Dec 06, 2007 at 02:37:01AM -0800, Thomas Sefzick wrote:
> works, but 'plot' would be better, so first 'splot' into a table and
> then use the resulting datafile as input:

There's another variaton, Thomas, that uses `set view map'; for
instance, to plot the contour map and gradient vector field of:

    f(x, y) = sin(x) + sin(y)
    
try:

    f(x, y) = sin(x) + sin(y)
    set multiplot
    set contour
    set cntrparam level 10
    set view map
    set xrange [-6:6]
    set yrange [-6:6]
    unset surface
    unset key
    set isosamples 100,100
    set samples 100,100
    splot f(x, y)
    unset contour
    set isosamples 30,30
    set samples 30,30
    set surface
    set key
    l = 0.5
    splot '+' using 1:2:(0.0):(l*cos($1)):(l*cos($2)):(0.0) with \
          vectors title "f(x,y) = sin(x) + sin(y)"

See it here:

    http://wikisophia.org/wiki/User:Danenberg#Vector_field