node table structure

The node table contains the nodes corresponding to the extremities of all links from the Link table. Each entry is the start or end point of at least one link in the Link table

The fields x and y are automatically updated by triggers based the nodes’ geometries.

THe geometry field has no elevation support, but the z field has been manually computed through geo-processing of DEM data

The table is indexed on node (its primary key)

Table Structure

Field	Type	NULL allowed	Default Value	Foreign key	Description
node*	INTEGER	NO			unique identifier of the node
x	REAL	YES			X coord set by POLARIS
y	REAL	YES			Y coord set by POLARIS
z	REAL	YES			Z coord set by POLARIS
control_type	TEXT	YES			Control type of the node (signal, all_stop, stop_sign)
zone	INTEGER	YES		Zone(zone)	zone identifier of the link
geo	POINT	NO	‘’

(* - Primary key)

The SQL statement for table and index creation is below.

create TABLE IF NOT EXISTS "Node" (
    "node"           INTEGER UNIQUE NOT NULL PRIMARY KEY,
    "x"              REAL,
    "y"              REAL,
    "z"              REAL,
    "control_type"   TEXT,
    "zone"           INTEGER,

    FOREIGN KEY("zone") REFERENCES "Zone"("zone") deferrable initially deferred
 );

select AddGeometryColumn( 'Node', 'geo', SRID_PARAMETER, 'POINT', 'XY', 1);
select CreateSpatialIndex( 'Node' , 'geo' );

create INDEX IF NOT EXISTS "NODE_NODE_I" ON "Node" ("node");