如何在Gnuplot中使用调色板绘制位置图？

如何绘制带有delta_x和delta_y位置值的图？我需要在每个点上使用调色板（或颜色条）来显示各自的时期（下面显示了我当前的绘图以及我要绘制的绘图示例）。

我当前的Gnuplot代码如下：

set fontpath '/System/Library/Fonts'
set term post color enh eps font "Helvetica" 14 

#Gnuplot script file for plotting data

#Set Line style
set style line 12 lw 1 ps 1 pt 8 # empty triangle
set style line 13 lw 1 ps 0.7 pt 81 #empty circle 

#Add Legend
set key top right box

# set plot
set xrange[1.2:0]
set xlabel "Relative R.A. (mas)" # set xlabel
set mxtics 4
set xtics 0, 0.1, 1.2

set yrange[0:1]
set ylabel "Relative decl.  (mas)"
set mytics 4
set ytics 0, 0.1, 1

plot "MOD1.dat" using 1:2 w points ls 13 lc rgb 'black' title "Data1", "MOD2.dat" using 1:2 w points ls 12 lc rgb 'gray' title "Data2"

我的数据如下：

 Data1:
 #Year           RA(mas)    DEC(mas)
 1993-06-26     0.36315     0.23913 
 1993-12-16     0.33392     0.28443
 1994-01-28     0.34606     0.30810
 1994-12-23     0.37139     0.32989
 1995-02-12     0.34050     0.29165
 1995-08-17     0.55405     0.42913
 1995-12-18     0.36928     0.2777
 1996-04-07     0.49601     0.31533 
 1996-12-13     0.43557     0.34637
 1997-11-14     0.36811     0.25562
 1998-06-02     0.55603     0.36268
 1998-12-07     0.52873     0.23110
 2000-11-12     0.45839     0.22572
 ieData2: 
#Year           RA(mas)     DEC(mas)
1993-06-26      0.63633     0.44645     
1993-09-18      0.63548     0.35586
1993-12-16      0.63161     0.41704
1994-01-28      0.27266     0.47256
1994-03-14      0.75819     0.65255
1994-04-21      0.69664     0.68481
1994-06-21      0.78735     0.72865
1994-08-29      0.91143     0.78274
1994-10-30      0.55326     0.43258
1994-12-23      0.67065     0.54423
1995-02-12      0.55778     0.51656
1995-08-17      1.01458     0.50502

谢谢你。