Geoscience Reference
In-Depth Information
(a)
(b)
(c)
(d)
(e)
FIGURE 9.3
(a) PARKAGENT model objects and agents (cars) with their identities shown as labels.
(b) LinkPP between street link (identified by LINKID) and parking place at the left and at the right side of a
link (identified by L_PPID, R_PPID). The side is defined with respect to the drawing direction of the link, and
the coordinates of the parking places (L_POS, R_POS) are defined according to their distance, in percentage
of the link length, from the link starting node. (c) Relationship ParkCar, between the parking place (identified
by PPID) and the car (identified by CARID) that occupies this parking place, has two attributes - time when
the car entered (ENTER) and time the car left the place (LEFT), LEFT = NULL for a car that still parks at the
parking place. (d) The relationship BldgLink between buildings and links is used for driving to destinations.
LinkID and BLDGID identify link and building, StreetSide denotes the side of the link with respect to the
link drawing direction, and BLDG_POS defines the location of the building according to its distance, in per-
centage of the link length, from the link starting node. (e) The relationship BldgPP between the building and
the parking place specifies parking places closest to the building entrances. BLDGID and PPID identify the
destination building and parking place, while DistM represents the distance, in meters, between the parking
place and the destination entrance.
Parking
place
Street
segment
0...1
1
0...n
1
1
0...n
Car
Building
0...n
0...1
FIGURE 9.4
Entity-relationship diagram for four entities - street segment, parking place, building and car
that are considered in the PARKAGENT model.
