help for airnet

Airline Traffic Network Construction

airnet , [ options ]

Description

airnet creates weighted and directed inter-airport or inter-city networks using data from the Bureau of Transportation Statistics' Origin and Destination Survey (DB1D).
(NOTE: This command does not affect the data in memory.)

Options

stub(str) specifies the stub (if any) used to name input (ticketstub.csv and couponstub.csv) and output (airnetstub.dta) files.

alpha(real) sets the alpha-level used for identifying likely business and leisure passengers.
The default is 0.05.

maxfare(real) and minfare(real) sets the maximum and minimum credible fares;
fares outside these limits are not used in calculations to identify business and leisure passengers.
The defaults are $5000 and $20.

legtype separately reports the number of passengers traveling on each type of leg in a route network (i.e. first, last, middle, and only).

matrix saves the route, origin-destination, business, and leisure networks in matrix form as separate comma-delimited files.

metro(new | old) aggregates airports into metropolitan areas (cannot be used with intl; see below for details).

intl(1 | 2 | 3 | 4) constructs a partial, international route network for the given quarter (cannot be used with metro; see below for details).

descriptives returns selected descriptives concerning the raw data in r().

Input

airnet requires two input files, which may be obtained from the BTS website. Both files must be located in the working directory.

ticketstub.csv - A comma-delimited file generated from the DB1BTicket database, containing only the following variables: ItinID, RoundTrip, Passengers, ItinFare.
available here

couponstub.csv - A comma-delimited file generated from the DB1BCoupon database, containing only the following variables: ItinID, MktID, Origin, Dest, SeqNum.
available here

Output

airnet produces several types of airline traffic networks, each stored in edgelist-format as a separate variable in airnetstub.dta:

Route - Edges indicates the number of passengers that flew from orig to dest.
Using the legtype option decomposes this total by the leg's position in the passenger's trip: first leg, last leg, a middle leg, or the only leg.

Origin-Destination (origdest) - Edges indicate the number of passengers that flew from an initial origin in orig to a final destination in dest; any intermediate stops are ignored.

Single-Destination Round-Trip (sdrt) - A subset of the origin-destination network that includes only passengers taking single-destination round-trip flights.

Business Passengers (business) - A subset of the SDRT network that includes only passengers that flew alone and paid a significantly above-average fare for travel between the same origin and destination airports.

Leisure Passengers (leisure) - A subset of the SDRT network that includes only passengers that flew with one or more companions and paid a significantly below-average fare for travel between the same origin and destination airports.

The -metro- option

Using the metro option aggregates airports into metropolitan areas, and thus results in the construction of intercity, rather than interairport, networks.
The aggregation is performed only for the 139 airports identified by the Federal Aviation Administration as "Primary Hubs" in 2010.
This option also creates a variable containing the great circle distance (in km) between metropolitan areas, which is stored in the "distance" variable in the airnetstub.dta and, if the matrix option is specified, is saved as a matrix.
The aggregation units are set by the suboption:

metro(old) - Airports are aggregated into Consolidated Metropolitan Statistical Areas (CMSAs) and Metropolitan Statistical Areas (MSAs) using 1999 US Census definitions.

metro(new) - Airports are aggregated into Consolidated Statistical Areas (CSAs) and Metropolitan Statistical Areas (MSAs) using 2009 US Census definitions.

The -intl- option

The intl option constructs a partial, international route network in addition to the complete, domestic networks constructed by airnet.
This network contains all intra-US route edges and all route edges between US and international airports, but does not include route edges between international airports.
It is stored in the "routeintl" variable in the airnetstub.dta, and if matrix is specified, is also saved as a matrix.
International origin-destination pairs are coded as missing.
This international route network is constructed from supplementary BTS T-100 data, and requires an additional input file:

intlstub.csv - A comma-delimited file generated from the T-100 International Segment database, containing only the following variables: Passengers, Origin, Dest, Quarter.

This file may be obtained from the BTS website (available here) and must be located in the working directory.
The downloaded data should cover all months in the desired year, and the quarter of the BTS DB1B data (i.e. the data in ticketstub.csv and couponstub.csv) should be identified in the intl option.
For example, if ticketstub.csv and couponstub.csv contain data on air traffic in the 2nd quarter (April-June) of 2010, the intlstub.csv file should contain data for all months in 2010 and the option should be specified as intl(2).

Saved Results

If the descriptives option is specified, airnet saves the following in r():

r(movements) - Number of intra-US passenger movements

r(airports) - Number of US airports

r(all_pass) - Number of intra-US passengers

r(sdrt_pass) - Number of intra-US passengers taking single-destination round-trips

r(lowfare) - Number of intra-US passengers paying less than the minimum credible fare

r(highfare) - Number of intra-US passengers paying more that the maximum credible fare

r(time) - Command running time, in seconds.

References

Neal, Z. P. 2010. Refining the air traffic approach: An analysis of the US city network, Urban Studies 47: 2195-2215. (CLICK FOR PDF)

Author

Zachary Neal
Department of Sociology
Michigan Sate University
zpneal@msu.edu