Description of one segment of a road. More...

Classes
class	DtTmpGeometry
	A class to hold the initially computed geometry for the inside lane of each segment in the path; used to make path adjustments before the final geometry is computed. More...

Public Member Functions
	DtRoadSegment ()
virtual	~DtRoadSegment ()
	DtRoadSegment (const DtRoadSegment &orig)
DtRoadSegment &	operator= (const DtRoadSegment &orig)
virtual DtRoadSegment *	clone ()
Initialization functions.
These functions compute the geometry of the lanes in the road segment.
virtual bool	initializeFromRailSegment (DtRailSegment railSegment, const Coordinate_System localCoordinateSystem, bool isDrivingOnLeft, DtRoadSegment *opposingSegment, bool debug=false)
	Fills in values for lane width, number of lanes, median width, and so forth from the rail segment.
virtual bool	calculateTemporaryExitGeometry (const double maxSmallBendRadius, const double vehicleWidth, const double headingChange, const double cosHeadingChange, const double sinHeadingChange, bool debug)
	Do the calculations for the curves connecting segments to determine the ideal and limiting values, and put into the tmpGeometry for the segment.
virtual bool	calculateTemporaryEntryGeometry (const double headingChange, const double cosHeadingChange, const double sinHeadingChange, bool debug)
	Do the calculations for the curves connecting segments to determine the ideal and limiting values, and put into the tmpGeometry for the segment.
virtual bool	initializeExitCurve (const double maxSmallBendTurnRadius, const double vehicleWidth, const double headingChange, const double cosHeadingChange, const double sinHeadingChange, bool debug=false)
	Initializes the exit curve geometry in this segment.
virtual bool	initializeEntryCurve (const double headingChange, const double cosHeadingChange, const double sinHeadingChange, bool debug=false)
	Initializes the entry curve geometry in the segment.
virtual void	setExitCurvesForEndingLanes ()
	Set the exit curve geometry and straight section length for lanes that don't connect downstream.
virtual void	connectWithNext (DtRoadSegment *nextSegment, bool isDrivingOnLeft, bool debug, bool fillOpposingSegment=true)
	Connects the next and previous segment pointers between this segment and the next one and connects the appropriate lanes via their connecting-upstream and -downstream lane members.
virtual void	determineIfIntersectionApproach (const DtRoadSegment *next)
	Determine if the downstream connection is an intersection.
virtual bool	allAltitudesDetermined () const
	This indicates that the altitude lookups needed to make the mySegmentToLocal transform (start and end points of the rail segment) and the slopes above (right edge points even with the start and end) have been found.
virtual void	setAllAltitudesDetermined (const bool b)
Lane Position Functions
These functions perform computations from a one-dimensional position along the centerline of a lane.
virtual DtRoadSegmentPart	segmentPart (const int laneN, const double positionAlongLane)
	Computes road segment part from lane position.
virtual double	distanceFromLaneEnd (const int laneN, const double positionAlongLane)
	Determines how far the position is from the end of the lane, including the exit curve.
virtual double	evenPositionAlongLane (const double positionAlongLaneA, const int laneA, const int laneB)
	Determines the position along laneB that is even with the position along laneA.
virtual bool	localPositionFromLanePosition (const int laneN, const double positionAlongLane, const double lateralOffset, bool isDrivingOnLeft, DtVector &localPosition, double &headingOffset, double &distanceBeyond) const
	Determine the position in local coordinates from the linear position along the lane and a lateral offset.
virtual bool	lanePositionFromLocalPosition (const DtVector localPosition, const int laneN, bool isDrivingOnLeft, double &positionInLane, double &laneOffset, bool debug)
	Compute the position of the given local position in the given lane of the segment.
Multi-Segment Lane Functions
These functions examine whether a lane continues downstream through multiple segments in the path.
virtual int	rightmostContinuingLane () const
	Finds the lane number (0-base) of the right-most lane that connects to the downstream road segment.
virtual int	findNearestContinuingLane (const int laneN, const double positionAlongLane, const double lookAheadDistance, bool debug=false)
	Looks downstream to see if the current lane connects through to the downstream segments.
virtual bool	laneContinuesForDistance (const int laneN, const double positionAlongLane, const double lookDistance, double &actualDistance, bool &pathContinues, bool debug=false)
	Checks to see if the given lane continues downstream, connecting to lanes in downstream links, for at least lookDistance.
virtual int	matchingLane (const double offset)
	Find the lane whose centerline offset best matches the given offset.
Set and Get Functions for Members
virtual double	heading () const
virtual void	setHeading (const double h)
virtual double	length () const
	This is the length of the associated rail segment.
virtual void	setLength (const double l)
virtual double	medianWidth () const
	Width of the median.
virtual void	setMedianWidth (const double w)
virtual DtString	roadName () const
	Name of the road containing this segment.
virtual void	setRoadName (const DtString &name)
virtual const DtCoordTransform &	segmentToLocalTransform () const
	Converts from a road-segment coordinate system to local database coordinates.
virtual void	setSegmentToLocalTransform (const DtCoordTransform &xform)
virtual int	numLanes () const
virtual void	setNumLanes (const int nLanes)
virtual DtLaneSegment *	lanes ()
virtual const DtLaneSegment *	lanes () const
virtual bool	isOneWay () const
virtual void	setIsOneWay (const bool oneWay)
virtual bool	exitIsRightTurn () const
virtual void	setExitIsRightTurn (const bool r)
virtual bool	entryIsRightTurn () const
	Indicates a positive heading change from the previous segment to this one, and that lanes to the right (outside) of the road have a shorter turn radius.
virtual void	setEntryIsRightTurn (const bool r)
virtual double	entryCurveEndOffset () const
virtual void	setEntryCurveEndOffset (const double o)
virtual double	exitCurveStartOffset () const
virtual void	setExitCurveStartOffset (const double o)
virtual bool	isIntersectionApproach () const
virtual void	setIsIntersectionApproach (const bool i)
virtual double	stopLineSetBack () const
virtual void	setStopLineSetBack (const double sb)
virtual double	speedLimit () const
virtual void	setSpeedLimit (const double limit)
virtual double	defaultSpeedLimit (const int numLanes)
	Provides the default speed limit for (any) road segment based on number of lanes.
virtual double	freeFlowSpeed () const
virtual void	setFreeFlowSpeed (const double ff)
virtual DtRoadSegment *	nextRoadSegment () const
virtual void	setNextRoadSegment (DtRoadSegment *s)
virtual DtRoadSegment *	previousRoadSegment () const
virtual void	setPreviousRoadSegment (DtRoadSegment *s)
virtual DtRoadSegment *	opposingSegment () const
virtual void	setOpposingSegment (DtRoadSegment *s)
virtual bool	isOpposing () const
virtual void	setIsOpposing (const bool opposing)
virtual DtTmpGeometry *	temporaryGeometry ()
	Get/set the temporary geometry computed from the input rail path; used to identify segments that are too short and remove or realign them so that the resulting path is physically feasible.
Road Design Constants
These functions return constants used to build the road path. They define how some of the geometry of the road features are interpreted as roads. They can be overridden to produce different road interpretations.
virtual double	minIntersectionBendAngle ()
	This defines how much of an angle between segments is required for the connection to be considered an intersection.
virtual double	intrxThresholdAngleToConnectEdgeLanes ()
	This defines a threshold between segments at an intersection that determines how lanes are connected.
virtual double	intrxThresholdAngleToConnectAllLanes ()
	This defines a threshold between segments at an intersection that determines whether all aligned lanes should be connected, vs only the inside lane.
virtual double	nonIntrxThresholdAngleToConnectEdgeLanes ()
	Same as above, but for segments that define a bend in a through street rather than an intersection.
virtual double	minimumLaneWidth ()
	The minimum lane width expected from the feature data.

Protected Member Functions
virtual void	findRightMostAlignedLane (DtRoadSegment *nextSegment, int &rightMostLane, int &nextSegmentRightMostLane, int &numAlignedLanes)
	Finds the rightmost lane that is aligned with a lane in the downstream segment, assuming they are collinear.
virtual void	findLeftMostAlignedLane (DtRoadSegment *nextSegment, int &leftMostLane, int &nextSegmentLeftMostLane, int &numAlignedLanes)
	Finds the leftmost lane that is aligned with a lane in the downstream segment, assuming they are collinear.

Protected Attributes
double	myLength
	The length of the underlying road feature, ie the rail segment.
DtCoordTransform	mySegmentToLocal
	Coordinate transformation from segment coordinates to local database coordinates.
bool	myAllAltitudesDetermined
double	myHeading
double	myNextHeading
	The segment downstream:
bool	myExitBendsRight
	Refers to the connection to the downstream segment:
bool	myEntryBendsRight
	Refers to the connection from the upstream segment:
double	myEntryCurveEndOffset
	TODO – the following two members aren't used.
double	myExitCurveStartOffset
	Similarly, where the exit curve starts, relative to the end of the segment.
int	myNumberLanes
DtLaneSegment *	myLanes
	A vector of lanes, with lane 0 the right-most, and lane myNumberLanes-1 the left-most (or vice versa for drive-on-the-left roads).
bool	myIsIntersectionApproach
	Indicates that the connection at the downstream end is an intersection.
double	myStopLineSetback
	Distance before end of straight segment where stop line is located.
double	mySpeedLimit
	If available; 0 indicates not set.
double	myFreeFlowSpeed
	This is the speed traffic flows on average, irrespective of the legal speed limit above.
double	myMedianWidth
	The width of the median in this (2-way) segment.
DtString	myRoadName
	The name of the road.
bool	myIsOpposing
	Indicates that this segment goes in the opposite direction of the related rail segment.
DtTmpGeometry	myTmpGeometry
	This information is used when constructing the road path to find modifications to the segments when they are physically impossible to connect together, ie because they are too short and change direction too quickly.

DtRoadSegment *	myPreviousSegment
	These come directly from the rail path, thus there is a connection to only on other road segment before and after.
DtRoadSegment *	myNextSegment
bool	myIsOneWay
DtRoadSegment *	myOpposingSegment
	Only valid if not a one-way segment.

Detailed Description

Description of one segment of a road.

Derived from information in a DtRailSegment. A road segment is information for traffic in one direction, and is linked to another DtRoadSegment for traffic in the other direction.

Constructor & Destructor Documentation

DtRoadSegment::DtRoadSegment ( )

virtual DtRoadSegment::~DtRoadSegment ( )

virtual

DtRoadSegment::DtRoadSegment ( const DtRoadSegment & orig )

Member Function Documentation

DtRoadSegment& DtRoadSegment::operator= ( const DtRoadSegment & orig )

virtual DtRoadSegment* DtRoadSegment::clone ( )

virtual

virtual bool DtRoadSegment::initializeFromRailSegment	(	DtRailSegment *	railSegment,
		const Coordinate_System *	localCoordinateSystem,
		bool	isDrivingOnLeft,
		DtRoadSegment *	opposingSegment,
		bool	debug = `false`
	)

virtual

Fills in values for lane width, number of lanes, median width, and so forth from the rail segment.

Computes a tentative coordinate transform from road segment to local coordinates.

Parameters

opposingSegment If this is null, then this function first creates a segment for traffic going the same direction as the rail begin-end direction, then calls itself recursively to create an opposing segment–a segment for traffic going the opposite direction to the rail segment begin-end direction.

Returns: true if setup was successful.

virtual bool DtRoadSegment::calculateTemporaryExitGeometry	(	const double	maxSmallBendRadius,
		const double	vehicleWidth,
		const double	headingChange,
		const double	cosHeadingChange,
		const double	sinHeadingChange,
		bool	debug
	)

virtual

Do the calculations for the curves connecting segments to determine the ideal and limiting values, and put into the tmpGeometry for the segment.

(This will be used to find and adjust segments that are too short.)

Parameters

maxSmallBendRadius When there is only a small angle between adjacent segments, a circular arc connecting them would have a really large radius. This would extend the curve into each segment really far and cause various problems. This parameter is a max radius limit to use in these cases.

Called in DtRoadPathFunctions::calculatePathTemporaryGeometry as part of setupRoadFromRailPath.

Parameters

vehicleWidth	This is width of a design vehicle. The radius of the curve between segments is kept small enough to prevent a vehicle of this width from moving over the lane edge on the inside of the turn. Except that Vehicles will often extend over the lane edge on the outside anyway. The radius is kept at least as large as the minimum design radius, which may mean that the vehicle will cut the corner.
headingChange	The change in heading to the next segment, in radians (+ to the right). If driving on the left of the road, this value should be negated from the true rail segment geometry.
cosHeadingChange	cos of heading change. A parameter to avoid repeated calculation (see initializeEntryCurve() )
sinHeadingChange	sin of headingChange
debug	A flag to generate verbose output on the sim console (DtWarn)

virtual bool DtRoadSegment::calculateTemporaryEntryGeometry	(	const double	headingChange,
		const double	cosHeadingChange,
		const double	sinHeadingChange,
		bool	debug
	)

virtual

Do the calculations for the curves connecting segments to determine the ideal and limiting values, and put into the tmpGeometry for the segment.

(This will be used to find and adjust segments that are too short.)

Parameters

headingChange	The change in heading to the next segment, in radians (+ to the right). If driving on the left of the road, this value should be negated from the true rail segment geometry.
cosHeadingChange	cos of heading change. A parameter to avoid repeated calculation (see initializeEntryCurve() )
sinHeadingChange	sin of headingChange
debug	A flag to generate verbose output on the sim console (DtWarn)

Returns: True if everything goes well, false if there is an error.

virtual bool DtRoadSegment::initializeExitCurve	(	const double	maxSmallBendTurnRadius,
		const double	vehicleWidth,
		const double	headingChange,
		const double	cosHeadingChange,
		const double	sinHeadingChange,
		bool	debug = `false`
	)

virtual

Initializes the exit curve geometry in this segment.

Calls calculateInsideExitCurveGeometry to get the geometry of the constraining lane, then calls calculateExitCurveGeometry on the other lanes.

Assumes the next- and previous road segment pointers have been set already. Assumes the entry curve has already been created.

Parameters

maxSmallBendTurnRadius	Not used, will be removed
vehicleWidth	Not used, will be removed.
headingChange	The change in heading to the next segment, in radians (+ to the right). If driving on the left of the road, this value should be negated from the true rail segment geometry.
cosHeadingChange	cos of heading change. A parameter to avoid repeated calculation (see initializeEntryCurve() )
sinHeadingChange	sin of headingChange
debug	A flag to generate verbose output on the sim console (DtWarn)

Returns: True if everything goes well, false if there is an error.

virtual bool DtRoadSegment::initializeEntryCurve	(	const double	headingChange,
		const double	cosHeadingChange,
		const double	sinHeadingChange,
		bool	debug = `false`
	)

virtual

Initializes the entry curve geometry in the segment.

Assumes that the next- and previous road segment pointers have been set already, and that the lanes have been connected. Uses a pre-computed turn radius for the left edge line of the segment–which comes from the exit curve of the previous segment. This assumes that the left edge of the previous segment connects to the left edge of this segment (the normal case).

Parameters

headingChange	The change in heading to the next segment, in radians (+ to the right). If driving on the left of the road, this value should be negated from the true rail segment geometry.
cosHeadingChange	cos of heading change. A parameter to avoid repeated calculation (see initializeEntryCurve() )
sinHeadingChange	sin of headingChange
debug	A flag to generate verbose output on the sim console (DtWarn)

Returns: True if everything goes well, false if there is an error.

virtual void DtRoadSegment::setExitCurvesForEndingLanes ( )

virtual

Set the exit curve geometry and straight section length for lanes that don't connect downstream.

The function finds the lane that connects that has the biggest (negative) offset for its exit curve, and uses that to set the end point of the lanes that don't connect. The exit curve offset will be set to this biggest offset, and the exit curve length will be set to zero.

virtual void DtRoadSegment::connectWithNext	(	DtRoadSegment *	nextSegment,
		bool	isDrivingOnLeft,
		bool	debug,
		bool	fillOpposingSegment = `true`
	)

virtual

Connects the next and previous segment pointers between this segment and the next one and connects the appropriate lanes via their connecting-upstream and -downstream lane members.

This function uses several parameters to guess which lanes should be connected. In general, if the bend is slight, then lanes in the two segments that are aligned with each other are connected. If the road bends more than nonIntrxThresholdAngleToConnectEdgeLanes, then the right-most lanes are connected instead.

If the connection between segments is a roadway intersection, then intrxThresholdAngleToConnectEdgeLanes is used for the threshold angle. A connection between segments is judged to be an intersection if determineIfIntersectionApproach is true (see that function).

If isDrivingOnLeft is true, then the choice of connected lanes is based on the negation of the bend angle between segments. ie, if the bend angle is 90 degrees to the left, but isDrivingOnLeft is true, then the rightmost lane will be connected to the downstream segment.

virtual void DtRoadSegment::determineIfIntersectionApproach ( const DtRoadSegment * next )

virtual

Determine if the downstream connection is an intersection.

In this base function, the connection is an intersection if the two connecting segments have different names (attributes of the road feature), if they have different one-way properties, or if the angle to the next segment is greater than minIntersectionBendAngle. If this is an intersection, then only the outer edge, "turn" lane is connected to the next segment.

virtual bool DtRoadSegment::allAltitudesDetermined ( ) const

inlinevirtual

This indicates that the altitude lookups needed to make the mySegmentToLocal transform (start and end points of the rail segment) and the slopes above (right edge points even with the start and end) have been found.

If this is false, then the altitudes haven't been found yet, possibly because streaming terrain wasn't yet loaded. This is only used when creating the road path.

virtual void DtRoadSegment::setAllAltitudesDetermined ( const bool b )

inlinevirtual

virtual DtRoadSegmentPart DtRoadSegment::segmentPart	(	const int	laneN,
		const double	positionAlongLane
	)

virtual

Computes road segment part from lane position.

LaneN is a 0-based lane number.

virtual double DtRoadSegment::distanceFromLaneEnd	(	const int	laneN,
		const double	positionAlongLane
	)

virtual

Determines how far the position is from the end of the lane, including the exit curve.

virtual double DtRoadSegment::evenPositionAlongLane	(	const double	positionAlongLaneA,
		const int	laneA,
		const int	laneB
	)

virtual

Determines the position along laneB that is even with the position along laneA.

Uses 0-based lane numbers.

virtual bool DtRoadSegment::localPositionFromLanePosition	(	const int	laneN,
		const double	positionAlongLane,
		const double	lateralOffset,
		bool	isDrivingOnLeft,
		DtVector &	localPosition,
		double &	headingOffset,
		double &	distanceBeyond
	)		const

virtual

Determine the position in local coordinates from the linear position along the lane and a lateral offset.

Parameters

laneN	The 0-based lane number.
positionAlongLane	The linear position from the beginning of the entry curve arc.
lateralOffset	The distance to the right from the centerline. Note that this is actually the distance toward the outside of the road, so if driving on the left this is the distance to the left of the centerline.
isDrivingOnLeft	True if roads are set up to drive on left. This causes the position and heading to be mirrored about the line from segment start point to end point.
localPosition	The corresponding position in local coordinates (output).
headingOffset	The offset from local "north" (1, 0, 0) of the position. This is based on the position along the entry or exit arc. (output)
distanceBeyond	If the position is not on the road segment, this output will indicate how far beyond the end of the segment the position is.

Returns: True normally, but false if the position is beyond this segment.

virtual bool DtRoadSegment::lanePositionFromLocalPosition	(	const DtVector	localPosition,
		const int	laneN,
		bool	isDrivingOnLeft,
		double &	positionInLane,
		double &	laneOffset,
		bool	debug
	)

virtual

Compute the position of the given local position in the given lane of the segment.

Returns: false if the point is not within the segment, true otherwise. If false, the positionInLane is just the

virtual int DtRoadSegment::rightmostContinuingLane ( ) const

virtual

Finds the lane number (0-base) of the right-most lane that connects to the downstream road segment.

If no lanes have a connecting downstream lane, then 0 (the right lane) is returned.

virtual int DtRoadSegment::findNearestContinuingLane	(	const int	laneN,
		const double	positionAlongLane,
		const double	lookAheadDistance,
		bool	debug = `false`
	)

virtual

Looks downstream to see if the current lane connects through to the downstream segments.

If so, returns the number of the current lane (laneN). If not, returns the lane number of a lane that connects. If there are more than one lanes that connect, it returns the nearest lane. If no lane in the current segment connects through for lookAheadDistance, then the nearest lane that connects to the next segment is returned. If there is no next segment, then the current laneN is returned. Checks segments downstream at least to a lookAheadDistance ahead. Lane numbers are 0-based.

virtual bool DtRoadSegment::laneContinuesForDistance	(	const int	laneN,
		const double	positionAlongLane,
		const double	lookDistance,
		double &	actualDistance,
		bool &	pathContinues,
		bool	debug = `false`
	)

virtual

Checks to see if the given lane continues downstream, connecting to lanes in downstream links, for at least lookDistance.

If so, returns true. If not, returns false. If the path(connected segments) ends before the lookDistance, the function will return false; however, pathContinues will also be set to false. Puts the distance the lane does continue in actualDistance.

Parameters

laneN is the current lane; 0-based.

virtual int DtRoadSegment::matchingLane ( const double offset )

virtual

Find the lane whose centerline offset best matches the given offset.

Returns a 0-based lane number (ie right lane is 0).

virtual double DtRoadSegment::heading ( ) const

inlinevirtual

virtual void DtRoadSegment::setHeading ( const double h )

inlinevirtual

virtual double DtRoadSegment::length ( void ) const

inlinevirtual

This is the length of the associated rail segment.

This is the same as the length of the straight part of the road segment if the entry and exit curves had 0 setback.

virtual void DtRoadSegment::setLength ( const double l )

inlinevirtual

virtual double DtRoadSegment::medianWidth ( ) const

inlinevirtual

Width of the median.

Only applies to 2-way segments. The lanes are offset half this width from the segment left edge.

virtual void DtRoadSegment::setMedianWidth ( const double w )

inlinevirtual

virtual DtString DtRoadSegment::roadName ( ) const

inlinevirtual

Name of the road containing this segment.

virtual void DtRoadSegment::setRoadName ( const DtString & name )

inlinevirtual

virtual const DtCoordTransform& DtRoadSegment::segmentToLocalTransform ( ) const

inlinevirtual

Converts from a road-segment coordinate system to local database coordinates.

The road segment coordinate system has +x in the direction from the start point to the end, +y to the right, and +z down. The y direction is the same whether driving on the left or not, so code that uses this transformation has to manually negate the y coordinate and the heading if driving on the left.

virtual void DtRoadSegment::setSegmentToLocalTransform ( const DtCoordTransform & xform )

inlinevirtual

virtual int DtRoadSegment::numLanes ( ) const

inlinevirtual

virtual void DtRoadSegment::setNumLanes ( const int nLanes )

inlinevirtual

virtual DtLaneSegment* DtRoadSegment::lanes ( )

inlinevirtual

virtual const DtLaneSegment* DtRoadSegment::lanes ( ) const

inlinevirtual

virtual bool DtRoadSegment::isOneWay ( ) const

inlinevirtual

virtual void DtRoadSegment::setIsOneWay ( const bool oneWay )

inlinevirtual

virtual bool DtRoadSegment::exitIsRightTurn ( ) const

inlinevirtual

virtual void DtRoadSegment::setExitIsRightTurn ( const bool r )

inlinevirtual

virtual bool DtRoadSegment::entryIsRightTurn ( ) const

inlinevirtual

Indicates a positive heading change from the previous segment to this one, and that lanes to the right (outside) of the road have a shorter turn radius.

Note that if driving on the left, this function returns the opposite, i.e. it is true if the road turned left on entry into this segment. In that case though the outside lane still has the shorter turn radius.

virtual void DtRoadSegment::setEntryIsRightTurn ( const bool r )

inlinevirtual

virtual double DtRoadSegment::entryCurveEndOffset ( ) const

inlinevirtual

virtual void DtRoadSegment::setEntryCurveEndOffset ( const double o )

inlinevirtual

virtual double DtRoadSegment::exitCurveStartOffset ( ) const

inlinevirtual

virtual void DtRoadSegment::setExitCurveStartOffset ( const double o )

inlinevirtual

virtual bool DtRoadSegment::isIntersectionApproach ( ) const

inlinevirtual

virtual void DtRoadSegment::setIsIntersectionApproach ( const bool i )

inlinevirtual

virtual double DtRoadSegment::stopLineSetBack ( ) const

inlinevirtual

virtual void DtRoadSegment::setStopLineSetBack ( const double sb )

inlinevirtual

virtual double DtRoadSegment::speedLimit ( ) const

inlinevirtual

virtual void DtRoadSegment::setSpeedLimit ( const double limit )

inlinevirtual

virtual double DtRoadSegment::defaultSpeedLimit ( const int numLanes )

virtual

Provides the default speed limit for (any) road segment based on number of lanes.

Used when the road segment is initialized from a rail segment, when the rail segment's speed is just a default value. Uses the constants defined in DtRoadConstants.

Parameters

numLanes is the number of lanes in one direction.

virtual double DtRoadSegment::freeFlowSpeed ( ) const

inlinevirtual

virtual void DtRoadSegment::setFreeFlowSpeed ( const double ff )

inlinevirtual

virtual DtRoadSegment* DtRoadSegment::nextRoadSegment ( ) const

inlinevirtual

virtual void DtRoadSegment::setNextRoadSegment ( DtRoadSegment * s )

inlinevirtual

virtual DtRoadSegment* DtRoadSegment::previousRoadSegment ( ) const

inlinevirtual

virtual void DtRoadSegment::setPreviousRoadSegment ( DtRoadSegment * s )

inlinevirtual

virtual DtRoadSegment* DtRoadSegment::opposingSegment ( ) const

inlinevirtual

virtual void DtRoadSegment::setOpposingSegment ( DtRoadSegment * s )

inlinevirtual

virtual bool DtRoadSegment::isOpposing ( ) const

inlinevirtual

virtual void DtRoadSegment::setIsOpposing ( const bool opposing )

inlinevirtual

virtual DtTmpGeometry* DtRoadSegment::temporaryGeometry ( )

virtual

Get/set the temporary geometry computed from the input rail path; used to identify segments that are too short and remove or realign them so that the resulting path is physically feasible.

This function accesses the structure without the const qualifier so that callers may change individual members.

virtual void DtRoadSegment::findRightMostAlignedLane	(	DtRoadSegment *	nextSegment,
		int &	rightMostLane,
		int &	nextSegmentRightMostLane,
		int &	numAlignedLanes
	)

protectedvirtual

Finds the rightmost lane that is aligned with a lane in the downstream segment, assuming they are collinear.

Returns the lane number (0-based), the corresponding lane number in the downstream lane, and the number of aligned lanes.

virtual void DtRoadSegment::findLeftMostAlignedLane	(	DtRoadSegment *	nextSegment,
		int &	leftMostLane,
		int &	nextSegmentLeftMostLane,
		int &	numAlignedLanes
	)

protectedvirtual

Finds the leftmost lane that is aligned with a lane in the downstream segment, assuming they are collinear.

Returns the lane number (0-based), the corresponding lane number in the downstream lane, and the number of aligned lanes.

virtual double DtRoadSegment::minIntersectionBendAngle ( )

inlinevirtual

This defines how much of an angle between segments is required for the connection to be considered an intersection.

Default value 0.7854.

If it is an intersection, then usually only the outer, "turn" lane is connected to the downstream segment (see parameter below). In radians. Note 45 degrees = 0.7854 radians. Note that if the path changes from two-way to one-way or vice versa, it is considered an intersection. TODO– this will be replaced with other information to determine whether there is an intersection.

virtual double DtRoadSegment::intrxThresholdAngleToConnectEdgeLanes ( )

inlinevirtual

This defines a threshold between segments at an intersection that determines how lanes are connected.

Default value 0.3.

When the bend is less than this angle, a lane is connected to the downstream lane that it aligns with most closely. E.g. if there is one lane in the upstream segment and two in the downstream, the best connection from the single lane will be to the left lane in the downstream segment, because they are closely aligned. However, when the bend is greater than the threshold, the single lane should be connected to the rightmost downstream lane (for right bends, and vice versa for left). This threshold is normally fairly small because the expected case is that the edge lanes are connected at an intersection.

virtual double DtRoadSegment::intrxThresholdAngleToConnectAllLanes ( )

inlinevirtual

This defines a threshold between segments at an intersection that determines whether all aligned lanes should be connected, vs only the inside lane.

Default value 0.2.

Intersections can be defined by one-way properties changing, or by the name changing, even if there isn't a bend in the road. If the intersection is fairly straight, then all lanes are aligned. If the bend is less than this angle (radians), all lanes will be connected. This should be less than the above threshold.

virtual double DtRoadSegment::nonIntrxThresholdAngleToConnectEdgeLanes ( )

inlinevirtual

Same as above, but for segments that define a bend in a through street rather than an intersection.

Default value 0.7854.

This is expected to be a higher threshold because the usual case should be for aligned lanes to connect; only when there is a significant bend are the lanes matched up from the right (left) edge inward. Making this = max-straight-road-bend-angle means that if a path doesn't bend enough to be an intersection, then the aligned lanes will be connected.

virtual double DtRoadSegment::minimumLaneWidth ( )

inlinevirtual

The minimum lane width expected from the feature data.

Default value 2.0.

Member Data Documentation

double DtRoadSegment::myLength

protected

The length of the underlying road feature, ie the rail segment.

DtCoordTransform DtRoadSegment::mySegmentToLocal

protected

Coordinate transformation from segment coordinates to local database coordinates.

Segment coordinates have the origin at the rail segment start point and are oriented with x toward the end point, y to the right, and z perpendicular to x and y.

bool DtRoadSegment::myAllAltitudesDetermined

protected

double DtRoadSegment::myHeading

protected

double DtRoadSegment::myNextHeading

protected

The segment downstream:

bool DtRoadSegment::myExitBendsRight

protected

Refers to the connection to the downstream segment:

bool DtRoadSegment::myEntryBendsRight

protected

Refers to the connection from the upstream segment:

double DtRoadSegment::myEntryCurveEndOffset

protected

TODO – the following two members aren't used.

See comment above. Where the entry curve ends and the straight section begins, relative to the segment start X.

double DtRoadSegment::myExitCurveStartOffset

protected

Similarly, where the exit curve starts, relative to the end of the segment.

DtRoadSegment* DtRoadSegment::myPreviousSegment

protected

These come directly from the rail path, thus there is a connection to only on other road segment before and after.

(Future implementation might be of a road network, thuse there would be multiple connections at intersections.)

DtRoadSegment* DtRoadSegment::myNextSegment

protected

bool DtRoadSegment::myIsOneWay

protected

DtRoadSegment* DtRoadSegment::myOpposingSegment

protected

Only valid if not a one-way segment.

int DtRoadSegment::myNumberLanes

protected

DtLaneSegment* DtRoadSegment::myLanes

protected

A vector of lanes, with lane 0 the right-most, and lane myNumberLanes-1 the left-most (or vice versa for drive-on-the-left roads).

This is offset by 1 from the railSegment convention, but matches the array index.

bool DtRoadSegment::myIsIntersectionApproach

protected

Indicates that the connection at the downstream end is an intersection.

Set in determineIfIntersectionApproach(). Affects whether all lanes are connected to the downstream segment, or just the edge lane.

double DtRoadSegment::myStopLineSetback

protected

Distance before end of straight segment where stop line is located.

(Note: in VRF 4.5 – not used yet.)

double DtRoadSegment::mySpeedLimit

protected

If available; 0 indicates not set.

double DtRoadSegment::myFreeFlowSpeed

protected

This is the speed traffic flows on average, irrespective of the legal speed limit above.

(Note: in VRF 4.5 – not used yet.)

double DtRoadSegment::myMedianWidth

protected

The width of the median in this (2-way) segment.

DtString DtRoadSegment::myRoadName

protected

The name of the road.

bool DtRoadSegment::myIsOpposing

protected

Indicates that this segment goes in the opposite direction of the related rail segment.

The opposing segments are filled out in the current implementation (4.5), but are not used.

DtTmpGeometry DtRoadSegment::myTmpGeometry

protected

This information is used when constructing the road path to find modifications to the segments when they are physically impossible to connect together, ie because they are too short and change direction too quickly.

These values are for the inner lane in the bend between segments– ie the lane that is constrained the most by geometry.

The documentation for this class was generated from the following file:

/exports/nfedora7-1/nightly/docs/vrforcesDevelopment.tot/include/vrfmodel/roadSegment.h

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