;This program plots B field components vs. year, between 1945 and 1995.

read,'Latitude, longitude: ',lat,lon
year=findgen(51)+45.
x=fltarr(51)
y=fltarr(51)
z=fltarr(51)
hor=fltarr(51)
dip=fltarr(51)
dec=fltarr(51)
for i=0,50 do begin
  igrf,lat,lon,year(i),xaux,yaux,zaux,horaux,dipaux,decaux
  x(i)=xaux
  y(i)=yaux
  z(i)=zaux
  hor(i)=horaux
  dip(i)=dipaux
  dec(i)=decaux
endfor
stop
again:
print,'Plot menu:'
print,'1. X'
print,'2. Y'
print,'3. Z'
print,'4. H'
print,'5. I'
print,'6. D'
print,'7. Exit'
print
read,'Enter choice: ',choice
case choice of
1: plot,year,x,xtitle='Year',ytitle='X',/ynozero
2: plot,year,y,xtitle='Year',ytitle='Y',/ynozero
3: plot,year,z,xtitle='Year',ytitle='Z',/ynozero
4: plot,year,hor,xtitle='Year',ytitle='H',/ynozero
5: plot,year,dip,xtitle='Year',ytitle='I',/ynozero
6: plot,year,dec,xtitle='Year',ytitle='D',/ynozero
7: goto, finish
endcase
if choice ne 7 then goto, again
finish:
end