;
pro fminmax, f,rmin,rmax,spval
;
rmin = 1.e36
rmax = -1.e36
missingval = float(spval)
n = long(n_elements(f)-1)
for i=0L,n do begin
  if (f(i) ne missingval and f(i) gt rmax) then rmax = f(i)
  if (f(i) ne missingval and f(i) lt rmin) then rmin = f(i)
endfor
end