link type table structure

This table collects all link types in the model with corresponding ranks, allowed vehicles and permission for the creation of turn pockets.

Turn pockets are only created if the values on turn_pockets are set to TRUE (not case-sensitive) OR if the field is not populated (default for older networks).

This flag does NOT, however, guarantee the creation of such pockets, as the need for them is only assessed during the creation of connections (see appropriate documentation for such)

Table Structure

Field	Type	NULL allowed	Default Value	Foreign key	Description
link_type*	TEXT	NO			Name of the link type (e.g. Freeway, Principal, Collector, etc.)
rank	INTEGER	NO	0		Rank of the link type. Lower rank implies higher hierarchy (e.g. Freeway = 10, Principal = 30, etc.)
use_codes	TEXT	NO	‘’		Modes allowed in the link, separated by a vertical bar
turn_pocket_length	REAL	NO	50		Length of turn pockets, if allowed in meters
turn_pockets	INTEGER	NO	1		Flag to allow the creation of turn pockets. 1 = TRUE, 0 = FALSE
speed_limit	NUMERIC	NO	0		Speed limit for the link type in m/s
alternative_labels	TEXT	YES			Alternative labels for the link type (e.g. Principal/Arterial)
notes	TEXT	YES			user notes

(* - Primary key)

The SQL statement for table and index creation is below.

create TABLE IF NOT EXISTS "Link_Type" (
    "link_type"             TEXT    NOT NULL PRIMARY KEY,
    "rank"                  INTEGER NOT NULL DEFAULT 0,
    "use_codes"             TEXT    NOT NULL DEFAULT '',
    "turn_pocket_length"    REAL    NOT NULL DEFAULT 50,
    "turn_pockets"          INTEGER NOT NULL DEFAULT 1,
    "speed_limit"           NUMERIC NOT NULL DEFAULT 0,
    "alternative_labels"    TEXT,
    "notes"                 TEXT
);