County-to-County Distance Matrix
The following
files contain a matrix of distances and network impedances (commonly
called a "skim tree") between each pair of county centroids
via highway, railroad, water, and combined highway-rail paths. The matrix
is called "kODp3," and was calculated in 2002 Dec using the
intermodal network ck23. It is designed for calibrating or estimating
spatial interaction models without the need to implement a distance
estimation method.
For ease of
download, the matrix is divided into six parts, file "kODp3-1"
containing paths with origin counties beginning with FIPS codes from
01 to 09 (AL to CT), and "kODp3-6" for origin FIPS starting
50 and above (VT through WY and Canada). Except for the initial header
record, they may be concatenated to form the complete matrix. Following
are the first four records of file 6:
# org, dest,"Oname ","Dname
", GCD, H-mi, H-imp, R-mi, R-imp, W-mi, W-imp,HRH-imp
50001,01001,"Addison
","Autauga ", 1075.2, 1272.4, 1203.6, 1396.2, 615.2, 2466.8, 703.5,
1094.2
50001,01003,"Addison ","Baldwin ", 1224.0, 1443.2, 1350.0, 1552.2,
688.7, 2152.2, 519.7, 1227.2
50001,01005,"Addison ","Barbour ", 1069.0,
1293.7, 1230.1, 1461.5, 726.6, 2586.6, 727.8, 1118.2
Each record
lists one county-to-county pair, by FIPS code, in order. Fields are
both fixed column and comma delimited. The fields are:
| Origin
FIPS |
I5
|
|
| Destination
FIPS |
I5 |
|
| Origin
name |
A8 |
plus
bracketing double quotes (") |
| Destination
name |
A8 |
|
| Great
circle dist |
F7.1 |
miles |
| Highway
miles |
F7.1 |
(explicit
decimal point) |
| Highway
impedance |
F7.1 |
|
| Rail
miles |
F7.1 |
|
| Rail
impedance |
F7.1 |
|
| Water
miles |
F7.1 |
|
| Water
impedance |
F7.1
|
|
| HRH
impedance |
F7.1 |
(Highway-rail-highway)
|
Miscellaneous
notes
The first record,
beginning with a "#" character, contains the field list, and is not
data.
The matrix is not quite symmetric because of numerous one-way facilities,
especially intermodal terminals.
Impossible routes (eg, highway from California to Hawaii) have a mileage
of -1.0 and an impedance of 99999.9.
Canadian cities have arbitrary "FIPS" codes above 80000.
Intermodal
impedance factors. Impedance units on each modal link were chosen
to be relative to the best facilities, which start out with about 1
impedance unit per mile (and 0.9 for rural Interstates). These "native"
impedances are multiplied by intermodal adjustment factors to bring
their approximate "costs" into common units. The intermodal factors
used were: 1/1 for highway 1/3.3 for rail 1/5.0 for inland barge 1/5.8
for Great Lakes 1/6.5 for marine shipping.
Water paths The miles/impedances for "water" trips allowed shipments
to use any of the 3 water modes (inland barge, Great Lakes, and marine)
and the intermodal terminals between them.
HRH trips. The only explicitly intermodal paths were forced to
start on a highway, pass through a highway/rail terminal, then through
another rail/highway terminal, and complete the trips by truck. Only
fixed terminals were used, but they could have been of any type or commodity,
not just TOFC/COFC. (The team-track model was not used.) Naturally,
impedances could be greater than highway alone.
Intrazonal trips. Intracounty trip length calculated as SQRT(area/pi)*0.76
times circuity factor (= 1.2). For water, this was reduced by 20% to
compensate for the probable geographic concentration of water shippers
in a county. For HRH intermode, intra-county trips were declared impossible.
Centroids. CONUS county centroids are 1990 residential population
centroids. (A handful are outside their boundaries.) Alaska, Hawaii,
and Canada aimed for the employment centroid, but were often offset
to fall on a network node. For new FIPS codes in 2000 a Census-supplied
geographical centroid is used. In particular, the Miami-Dade (12086)
centroid is areal, while the old Dade Co centroid is population-weighted.
Because both old and new FIPS codes are in the O-D list, the O-D matrix
is slightly larger, and the user must decide which entries will be used
or ignored.
Download kODp3
matrix portions (These files compressed by WinZip.)
| |
kODp3-1
(AL-CT) (27 MB)  |
kODp3-4
(MT-OH) (46 MB) |
| |
kODp3-2
(DE-IA) (50 MB) |
kODp3-5
(OK-UT) (57 MB) |
| |
kODp3-3
(KS-MO) (62 MB) |
kODp3-6
(VT-CN) (32 MB) |
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