How to Use MultiNet Shapefile and OSL
Parent topic: How to Use MultiNet Shapefile and OSL

Level Differences and Structures

Levels

Not all Transportation Elements are on the same level. Therefore, a Road Element should not be connected to its intersecting Road Elements if it overpasses them.

If intersecting Transportation Elements are at the same level, they are connected in the Network by a "Crossing at Grade." A Turn routing advisory may be generated at this Junction if no maneuver restrictions or traffic flow directions apply that could prevent the turn.

If intersecting Transportation Elements are not at the same level, they are at a

"Grade Separated Crossing."

Crossing at Grade

Transportation Elements are bounded by Junctions. Level differences can be checked by comparing the "From" and "To" Junction Elevation for two adjoining Transportation Elements (ELEV field in the jc layer). The value is 0 if all the Transportation Elements bounding the same Junction are at the same level and are therefore "crossing at grade."

Grade Separated Crossing (GSC)

  • The position where GSC elements cross must be represented by a Point Brunnel.
  • A GSC is a relationship and must contain at least two elements next to the Point Brunnel.
  • In Shapefile format, see examples below for layers and fields involved in identifying a grade separated crossing.
TABLE OR LAYER FIELD GDF ATTRIBUTE ATTIBUTE VALUES ATTRIBUTE DESCRIPTION
ps (Point structure) STRUCTTYP BT 0, 1, 2, 3, 4 Brunnel Type

0 = Not applicable;

1 = Bridge;

3 = Aqueduct;

4 = Tunnel.
nw (Network) PARTSTRUC 7X 0, 1, 2 Part of a Structure

0 = Not applicable;

1 = Part of a tunnel;

2 = Part of a bridge.
se (Structure Transportation Elements Relation) ELEV 5U -9 to 9 Transportation Element Level in Grade Separated Crossing

Negative numbers indicate element is below another element in the relationship; Positive numbers indicate element is above another element in the relationship. Elements are identified by their IDs in this table.

Other Indicators for Different Levels

Besides the layers and fields indicated in the example above, there are other indicators in MultiNet data that represent elements at different levels:
TABLE OR LAYER FIELD GDF ATTRIBUTE ATTIBUTE VALUES ATTRIBUTE DESCRIPTION
jc (Junction) ELEV 8Z -9 to 9 Z-Level Information

Negative numbers indicate junction is below ground level; Positive numbers indicate junction is above ground level. Default is "0" (Ground level)
nw (Network) F_ELEV

T_ELEV

 8Z -9 to 9 Z-Level Information

Negative numbers indicate junction is below ground level; Positive numbers indicate junction is above ground level. Default is "0" (Ground level)
ls (Line Structure) STRUCTTYP BT 1, 3, 4 Brunnel Type

1 = Bridge;

3 = Aqueduct;

4 = Tunnel.
Note: See also "Grade Separated Crossing - Brunnel" in the Appendix section of the MultiNet Data Specifications and Data Model document.

Structure at Grade Separate Crossing Without a Junction: Relationships

If the crossing is at different levels and there is no reason for a Junction at the crossing, the Grade Separate Crossing Relationship is defined by the Structure situated on the Crossing and the two Transportation Elements.

Figure: Structure at Grade Separate Crossing

Structures

At the location of a grade separate crossing, a Structure is present to model the height difference between the different Elements crossing each other. A Structure is defined by two elements: a Bridge, Tunnel or Aqueduct, and another Element that is an overpass or underpass. A Structure is modeled in the database by a point, a line or an area. See Structures (Brunnels) earlier in this user guide for Shapefile layer identification for each structure type. The Elements that form part of a Structure can be:
  • Road Element;
  • Ferry Elements;
  • Rail Elements;
  • Waterways;
  • Junctions; and
  • Address Area Boundary Elements.
A Relationship between every Element forming part of the Structure is established to show the relative level that each Element has, above or below. These Relationships are included in the se Structure Index table. Every Element is linked via an ID to its geometrical Structure in the ps or ls layer. Every Element has an internal sequential number within the Structure. Every Relation between two Elements also has a number that occurs twice logically, once for every Element record.
Note: No Grade Separate Crossing level differences are defined for Area Structures (as). The level differences are related to the Line Structures.
The Feature Element Type defines which kinds of Elements are involved in a Structure: Transportation Element (Road Element, Ferry Element, Address Area Boundary Element); a Railway Element; or a Water Area/Center Line. In some cases, (for example, a Railway Crossing), a Junction takes part in the Relations defined within the Structure.
Parent topic: How to Use MultiNet Shapefile and OSL