Create annotate data set, REFLIB.CENTER, from
MAPS.USCENTER. The annotate data set labels each state with a two-letter
abbreviation. MAPS.USCENTER provides the x and y coordinates for the labels.
FLAG, which is initially turned off, signals when external labeling is in
effect. The labels are drawn after the map because the value of WHEN is
a
(after).
data reflib.center;
length function $ 8;
retain flag 0 xsys ysys '2' hsys '3' when 'a'
style 'swiss';
set maps.uscenter
(where=(fipstate(state) ne 'DC')
drop=long lat);