# Ruby/PGPLOT example: pgcont

### code

    require "narray"
    require "pgplot"
    include Pgplot

    # Preparing data
    x = NArray.sfloat(40,1).indgen!(1)
    y = NArray.sfloat(1,40).indgen!(1)
    map = NMath.cos( NMath.sqrt(x*2)*0.3 - y*0.4/3 ) * NMath.cos( x*0.4/3 ) \
          + (x-y)/40
    n = 21
    level = NArray.sfloat(n).indgen! * (map.max-map.min)/n + map.min

    # Draw contour map
    pgopen
    pgenv(1,40,1,40)    # set "Plotter Environment" and draw box.
    pgsci(3)            # set Color Index to Green.
    pgcont  map, level

### output

Ruby/PGPLOT by Masahiro Tanaka