All of the GfK and most of the traditional
map data sets that are provided with
SAS/GRAPH software contain four coordinate variables (X, Y,
LONG, and LAT). When all four coordinate variables are present, X
and Y are always projected values that are used by the
SAS/GRAPH procedures (by default). However, you
might want to use the LONG and LAT variables to reproject the map
using a different projection type. If you need to use the unprojected
values that are contained in the LONG and LAT variables, then do the
following tasks:
-
Project the spherical
coordinates (latitude and longitude) by using the GPROJECT procedure
with its LATLON option, which uses the LAT and LONG variables instead
of the X and Y variables.
Note: LONG and LAT variables in
GfK map data sets are in degrees. In traditional map data sets the
LONG and LAT variables are in radians or degrees.
-
Use the output data
set from GPROJECT, which now contains Cartesian coordinates, as your
input map data set by specifying it in the MAP= value in the GMAP
procedure