In reply to Jim Loughlin.

Thanks for mentioning that. I chose the Sashelp.USCity data set because it contains projected coordinates such as you would get from PROC GPROJECT. The (x,y) pairs are planar, so Euclidean distance is valid. (However, the distances are not in any standard units like miles or kilometers.) If you plot the (long, lat) of the cities, the map will be distorted.