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Road Layers

VTBuilder supports networks of transportation elements.  The topology is represented by nodes (intersections) and roads (a centerline path between two nodes).

Road data is imported from raw data sources, and saved to a compact Road Map Format (RMF). You can load multiple files, merge them, and delete areas that are not of interest.  Traffic direction and intersection behavior can be modelled and easily edited.

VTBuilder can import road data from these formats:

• USGS DLG-O (Digital Line Graph - Optional format)
• USGS DLG-SDTS
• US Census TIGER
• ESRI Shape files (SHP) and other GIS vector formats

Display

Roads are displayed with color that indicates their properties:

	Black: Normal (paved) road
	Brown: Unpaved (dirt) road
	Thick Red: Highway
	Grey: Gravel
	Dotted Brown: Trails
	Dashed Black: Railroad

For nodes, the colors are:

	Blue: NONE, uncontrolled
	Green: ALL LIGHTS, controlled intersection with all lights
	Red: ALL STOPS, controlled intersection with all stop signs
	Dotted Green: LIGHTS, controlled intersection with at least one traffic light
	Dotted Red: STOP SIGN, controlled intersection with at least one stop sign

Colors are inverted when the road or node is selected.

Road Menu

• Select/Modify Roads
  • In this mode, you may select roads in the road map by left clicking on them (click again to deselect.)  Double clicking will bring up that roads properties in a dialog box.  You may also modify multiple roads at once by selecting multiple roads and then right clicking anywhere on the road map.
  • Road properties include:
    • Highway number
    • Number of lanes
    • Sidewalk
    • Parking (presence of vehicle-width area of pavement along road)
    • Margin (presence of paved shoulder)
    • Road surface type
• Select/Modify Nodes
  • In this mode, you may select nodes in the road map by left clicking on them (click again to deselect.)  Double clicking will bring up that node's properties in a dialog box.  You may also modify multiple nodes at once by selecting multiple nodes and then right clicking anywhere on the road map.
  • Node properties include:
    • Intersection Type: Signal lights, Stop sign, or Uncontrolled (None).
    • Behavior of each of the road at the intersection point.  Each road is associated with a number as seen on the diagram on the right side of the dialog box.
      • A red outline of an octagon denotes a stop sign for the road at the given node.
      • A solid circle denotes a signal sign for the road at the given node.  Signal lights of like color (red or green) indicate linked signal lights (determined automatically.)  A black circle indicates that the signal light hasn't been set up properly.  Simply force the intersection type to signal lights to fix the problem.
      • If the road is uncontrolled, there will not be any symbol.
• Select Whole Roads
  • Click on a road, and VTBuilder will attempt to select all adjacent roads that constitute a single conceptual "road".  For example, you can use this to select an entire highway at once.
• Set Road Direction
  • Adjust traffic direction on roads by left clicking on the road.
    • <> - two-way traffic
    • > or < - one-way traffic, in direction of the arrow.
• Edit Road Points
  • In this mode, you can use the mouse to drag individual points of the roads.  Click on any road to select the points in that road, then click and drag those points to move them.  Note that intersections are not currently moved correctly.
• Show Nodes
  • Toggles the display of nodes (intersections).  Turning this off is useful to make roads faster to display and edit.
• Select Highway Number
  • Simply enter the number of the highway you want selected.
• Clean RoadMap
  • This powerful feature will perform a number of steps to fix errors in current road layer.  This is very important because raw sources of road data such as USGS DLG files often contain dangerous anomalies.  The following actions are performed:
    • Merge Redundant Nodes
      • Merges nodes that are extremely close to each other.  This function joins roads that were cut off on adjacent source files.  However, the roads are still separate.
    • Remove Degenerate Roads
      • Removes small roads that don't go anywhere (i.e. start and end at same point and have less than 3 points.)
    • Remove Unnecessary Nodes
      • Eliminates nodes and merges the 2 roads into one road if the 2 roads have the same properties.
    • Clean Road Points
      • Ensures that roads end on nodes and eliminates any repeating points.
    • Delete Dangling Roads
      • Delete roads that either:
        • have the same start and end nodes and have less than 4 points
        • have less than 2 points, regardless of start or end nodes.
    • Remove Unused Nodes
      • Deletes nodes with no roads.
    • Fix Overlapped Roads
      • Fix when two different roads meet at the same node along the same path
    • Fix Extraneous Parallels
      • Delete roads that are really close to other roads and lead nowhere.
    • Split Looping Roads
      • Splits a road that has the same start and end point.  Road will be split at the middle point and a new uncontrolled node will be created between the 2 new roads.

Use of RMF Files

In order to use the RMF files you have generated, copy them to a folder named RoadData on any of your data paths.  The next time you run Enviro, they will appear on the "Roads Filename" drop-down control in the Terrain Parameters dialog.

Currently Unimplemented:

• Merge 2 nodes.
  • Merges the 2 selected nodes.
• Path Finder
  • Tool to create a path for a vehicle to follow in the Enviro Program.
  • There are 3 steps:
    • Select the start node.
    • Select roads to create the path.  This can be done in 2 ways.  First, you can choose another node and let VTBuilder find the shortest path from the start point to the selected point ( on the toolbar - default setting.)  Second, you may also select individual roads to create the path - you must choose connected roads ( on the toolbar.)
    • Save the path by clicking on in the toolbar.