下面的小程序是将两个直方图叠加到一块的一个模板

pro plotplothist
readcol,'/root/afuwuqicopy/afuwuqicopy/rho350/copy/stn/stnmass.txt',F='i,f,f,f',index,fluxf,tempf,massf
readcol,'/root/afuwuqicopy/afuwuqicopy/aCO12/plot/mass.txt',massg,index1,index2,tempg,fluxg
a=massf
b=massg
LoadCT, 40, NColors=100, Bottom=1, /Silent
set_plot,'PS'
filename='/root/afuwuqicopy/afuwuqicopy/rho350/copy/stn/fg.eps' ; set the file name of the output ps file
device,file=filename,/ENCAPSULATED,/COLOR, BITS=8,xsize=xsize,ysize=ysize
plothist,a, bin=0.2,COLOR=99,xtitle='M/M'+sunsymbol(),ytitle='N';
plothist,b, bin=0.2,COLOR=20,/OVERPLOT; If set, will overplot the data on the current plot
device,/CLOSE
print,'program end'
end