to phase in that part of the program, beginning with the most heavily impacted areas close to the airport, and work their way out."

Using ArcView and AutoCAD, Psomas expanded the original database to encompass additional areas in the five jurisdictions surrounding LAX. The process included updating general community plans and incorporating changes in jurisdictions, zoning and housing. The firm also populated the database with local-use codes, parcel numbers, TRW information, census data from TIGER line files and Thomas Brothers street maps. General community plans were then overlaid on the basemaps, and the noise contours placed over these.

With ArcView AVENUE and a previous ANMP report as a template, Psomas programmers developed a structured query language that automated many of the complex steps involved in querying the database, and in identifying and quantifying spatial relationships.

Wyle used the data and GIS application provided by Psomas to identify parcels within the contours; develop tables, reports and maps for noise mitigation plans; and calculate cost estimates and construction schedules -- all required for the annual report. Since neither Wyle nor NMB is a high-end GIS developer, the application enabled them to produce the ANMP report in considerably less time than with earlier methods.

"What used to take a month," said Psomas Project Manager Matt Caraway, "now takes three to four days."

"By automating much of the report," Adams added, "Psomas enabled all our GIS users to produce a relatively sophisticated product regardless of their skill levels."

Projected Superjets Noise

Psomas is also assisting LAX master planners Landrum and Brown in analyzing the projected noise from 550-passenger superjets now on the drawing boards. Airliners of the 21st century will have larger, more powerful engines and will need runways of two miles and longer. At this point, however, runway configurations for LAX are in the study phase. Final approval depends on the Los Angeles City Council and numerous federal and state regulatory agencies.

Psomas' role in the project is similar to its work with the ANMP; the firm provides the database, and overlays the projected noise contours from Landrum and Brown onto the updated basemaps. Planners use the data to calculate the probable noise impact on surrounding communities.

GIS enabled LAWA not only to expedite the complex process of documenting the airport noise mitigation program, but, as Adams pointed out, it also enabled them "to get a better handle on the scope of the program," particularly in identifying and scheduling residences for sound-insulation construction. The technology is currently helping LAX airport planners estimate with greater accuracy some of the environmental costs of accommodating the next generation of superjets.

Bill McGarigle is a writer specializing in communication and information technology.

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