GMAP Procedure

Special Traditional Data Sets for Annotating Maps

There are several data sets in the MAPSSAS library that enable you to easily label maps. These data sets contain coordinates for map features such as cities, but cannot be used as map data sets.
MAPS.USCENTER
contains the coordinates of the visual center of each state in the U.S. and Washington, D.C.. It also contains coordinates in the ocean for states that are too small to contain a label. There are two pairs of variables for locating labels using Annotate data sets. The X and Y variables are projected and can be used with the MAPS.US and MAPS.USCOUNTY data sets. The LONG and LAT variables are unprojected longitude and latitude in radians and can be used with the MAPS.STATES, MAPS.COUNTIES, and MAPS.COUNTY data sets.
MAPS.USCITY
contains the locations of selected cities in the U.S. Many city names occur in more than one state, so you might have to subset by state to avoid duplication. There are two pairs of variables for locating labels using Annotate data sets. The X and Y variables contain projected coordinates and can be used with the MAPS.US and MAPS.USCOUNTY data sets. The LONG and LAT variables contain the unprojected longitude and latitude in radians. These can be used to place labels on the MAPS.STATES, MAPS.COUNTIES, or MAPS.COUNTY data sets.
Duplicate observations can be listed in the output data set. This occurs because the map data set includes towns, villages, hamlets, and other non-city areas that can share the same name with a city. Differentiate the output with the FEATYPE variable, which contains the area type.
For details about each of these data sets, see the MAPS.METAMAPS or the MAPSSAS.METAMAPS data set.