Summary

The above map depicts potential problem areas in the U.S. air system. The map was created by displaying three map layers

First, airports having severe congestion were identified and mapped by linking the AIRPORT map layer to the attribute table AIRPORT3.DBF and selecting facilities for which "cong_level" (congestion level) equals "S" (severe).

Next, heavily traveled routes were identified and mapped by linking the AIRWAY map layer to the attribute layer AIRWAYL1.DBF and selecting links for which "totpass" (total passengers) is greater than 1.5 million.

Finally, the recent pattern of population growth is displayed by using the ArcView sample data, which includes two fields called "pop90" (population in 1990) and "pop96" (population in 1996).

The map shows that some severely congested airports, such as Miami, Salt Lake City, and Seattle-Tacoma, are in high-growth states but are somewhat peripheral to the national system. Others, such as Chicago (O'Hare) and Los Angeles, are in states with lower growth rates but are linked to more high-volume routes; capacity problems at these airports will have far-reaching impacts. Dallas - Fort Worth has severe congestion, is in a relatively high-growth state, and is linked to several high-volume routes.

This map shows the usefulness of GIS in uncovering relationships at the national level, but more disaggregated data are needed to make recommendations at specific airports.