county skims table structure

The county skims table contains the travel distance between each of the counties within the modelled region. It is used by the CRISTAL freight model for high-level movement synthesis.

Table Structure

Field	Type	NULL allowed	Default Value	Foreign key	Description
county_orig	INTEGER	NO	0		The origin county FIPS code
county_dest	INTEGER	NO	0		The destination county FIPS code
great_circle_distance	REAL	YES	0		The great circle distance between the two counties (units: meters)
highway_distance	REAL	YES	0		The shortest routable highway distance between the two counties (units: meters)

(* - Primary key)

The SQL statement for table and index creation is below.

CREATE TABLE IF NOT EXISTS "County_Skims" (
    "county_orig"             INTEGER NOT NULL DEFAULT 0,
    "county_dest"             INTEGER NOT NULL DEFAULT 0,
    "great_circle_distance"   REAL             DEFAULT 0,
    "highway_distance"        REAL             DEFAULT 0
);