# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'polargrid.2.png'
set border 4096 front lt black linewidth 1.000 dashtype solid
set angles degrees
set tics front
set key title "Polar grid with masking" enhanced font ":Bold"   center
set key rmargin top vertical Right noreverse enhanced autotitle nobox
set key noinvert samplen 0.5 spacing 1 width 0 height 0
unset key
set view  equal xyz
set size ratio -1 1,1
set style data lines
unset xtics
unset ytics
set rtics  norangelimit 50 
set rrange [ * : * ] noreverse noextend
set lmargin  5
set rmargin at screen 0.7
unset colorbox
NO_ANIMATION = 1
## Last datafile plotted: "silver.dat"
## Last plot was a multiplot
# saved multiplot
set multiplot
set key title "Polar grid with masking"
set polar grid theta [-20:30] r [*:*]
plot 'silver.dat' using 1:2:3 with surface title "qnorm 1",      '' using 1:2:3 with points pt 7 lc "green" title "with points"
unset key
set polar grid theta [30:120] r [0:200]
plot 'silver.dat' using 1:2:3 with surface title "qnorm 1",      '' using 1:2:3 with points pt 7 lc "green" title "with points"
set polar grid theta [120:-20] r [0:100]
plot 'silver.dat' using 1:2:3 with surface title "qnorm 1",      '' using 1:2:3 with points pt 7 lc "green" title "with points"
unset multiplot