Node parameters can be individually set for each graph node. The parameters for node shapes are defined under Node Parameters in the Inspector.
Note:
Parameters (attributes) can be mapped to Default, User, Object, or to a map layer. See Mapping Attributes for details.
Node type parameter
Several parameters are available for the user to control the resulting node shapes. Node parameters define the type of the node and specify geometry details such as the radius of the arcs.
Type (attr type) | |
Specifies the type of the node. Crossing, Junction, Roundabout, or Freeway. | |
Crossing |  |
Junction |  |
Roundabout |  |
Freeway |  |
General node parameters
The following tables describe the parameters that are common to all the node types:
Intersection Angle Minimum (attr angleThreshold) | |
Minimum angle between streets before they automatically start bending to avoid each other. It is ignored for freeways. | |
Crossing with Intersection Angle Minimum set to 30. Note the streets bending to avoid each other. |  |
Crossing with Intersection Angle Minimum set to 10. |  |
Precision (attr precision) | |
Specifies the level of detail. Value must be in the range [0, 1]. | |
Crossing shapes with Precision = 0.1. |  |
Crossing shapes with Precision = 0.3. |  |
Create Shape (attr shapeCreation) | |
Enable or disable the shape geometry creation from the node. |
Crossing and junction parameters
The Crossing, Freeway, and Junction parameters have the following parameters:
Curb Radius (attr minArcRadius) | |
The minimal arc radius. For freeways, a higher value (>20) is better suited. | |
Given in absolute length units. | |
Crossing shapes with Curb Radius = 0. |  |
Crossing shapes with Curb Radius = 5. |  |
Block Corner (atrr cornerStyle) | |
Either Arcs or Straight. When set to the latter, blocks get simpler. | |
Border with Block Corner set to Arcs. |  |
Border with Block Corner set to Straight. |  |
Note:
The Block Corner parameter is not available when Type is set to Freeway.Roundabout parameters
When Type is set to Roundabout, the roundabout creation uses the following parameters:
Roundabout Island Radius (attr innerRadius) | |
Defines the radius of the inner circle (the island shape). |
Roundabout Street Width (attr streetWidth) | |
Defines the width of the roundabout street lane. | |
A roundabout with Roundabout Island Radius = 5 and Roundabout Street Width = 10. |  |
A roundabout with Roundabout Island Radius = 10 and Roundabout Street Width = 5. |  |
Curb Radius (attr minArcRadius) | |
The minimal arc radius. For freeways, a higher value (>20) is better suited. | |
Given in absolute length units. | |
Crossing shapes with Curb Radius = 0. | |
Crossing shapes with Curb Radius = 5. | |
Principal street selection
The Junction and Freeway node types make use of the principal street to determine the node geometry.
Note:
The principal street is specified using either the street tool, or by setting the object attribute principleStreetStart or principleStreetEnd on adjacent streets as appropriate.
Examples
| Simple curve | |
Valence-two nodes (nodes between two graph segments) usually lead to curves or links between the segments. Note:For valence-one (nodes at the end of a row of segments / cul-de-sac) or valence-two nodes, it does not matter whether the type is Crossing or Junction. |  |
| Dead end street | |
By setting the type of a valence-one node to roundabout, you can model a cul-de-sac. |  |
| Junction | |
Junctions, as opposed to crossings, don't break a major street. Minor streets are connected to the major street by junction entries. Note:The two segments with the maximal street widths are automatically treated as a major street. |  |
Autogenerated connection attributes
Connection attributes provide basic information about the underlying graph and give context information. CGA rules may want to access the following attributes.
shapeType | Specifies the type of the node. Crossing, Junction, Roundabout, or Freeway. |
valency | The number of street segments adjacent to a street node. Valency is added to all node shapes. |
Note:
Connection attributes are object attributes of the graph node and are inherited to the shape, indicated by the italic font in the shape's Inspector.