Key

$B=q<0(B :

        set key
        set key <x>,<y>{,<z>}
        set nokey
        show key

$B:BI8(B <x>, <y>, (splot $B$K$*$$$F$O(B <z> $B$b(B) $B$O!"$3$N@bL@$r$I$3$KG[CV$9(B $B$k$+$r;XDj$7$^$9!#$3$N@bL@$O!"0l9T$K0l6J@~J,$:$D6J@~$N?t$@$1I=<($5$l(B $B$^$9!#3F9T$K$O:8B&$K6J@~$HF1$8@~$,0z$+$l!"$=$N1&B&$K(B plot$B%3(B $B%^%s%I$+$iF@$i$l$kJ8;zNs$rI=<($7$^$9!#$3$NJ8;zNs$rJQ99$9$kJ}K!$K$D$$(B $B$F$O(B plot title $B$r;2>H$7$F$/$@$5$$!#$3$l$i$N9T$O!"J8;z$HD>@~$N4V$r(B $B$=$m$($F@0Ns$5$l$^$9!#(Bset key $B%3%^%s%I$G;XDj$9$k:BI8$O!"$3$N@0Ns$N(B $B0LCV$r;XDj$9$k$3$H$K$J$j$^$9!#(Bplot $B$G$O(B x $B$H(B y $B$,;2>H$5$l!"(Bsplot $B$G$O(B x, y, z $B$N;0$D$,;2>H$5$l$$$:$l$b%0%i%U$HF1$8:BI87O$G;XDj$9$k$3$H(B $B$K$J$j$^$9!#(B

$B>l9g$K$h$C$F$O$3$N@bL@$N0lIt$^$?$OA4It$,6-3&$N30$K$O$_=P$9$3$H$b$"$j(B $B$^$9!#$3$N>l9g8+=P$7$J$I$H=E$J$C$F$7$^$&$3$H$b$"$j!"$^$?=PNOAuCV$K$h$C(B $B$F$O%(%i!<$r@8$8$k$3$H$b$"$j$^$9!#(B

$BNc(B :

$B4{Dj$N0LCV$K@bL@$rI=<($7$^$9(B :

        set key

        set nokey

        set key 2,3.5,2