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vtkProjectedTerrainPath Class Reference

project a polyline onto a terrain More...

#include <vtkProjectedTerrainPath.h>

Inherits vtkPolyDataAlgorithm.

Public Types

enum  { SIMPLE_PROJECTION =0, NONOCCLUDED_PROJECTION, HUG_PROJECTION }
 

Public Member Functions

void SetSourceConnection (vtkAlgorithmOutput *algOutput)
 
void SetSourceData (vtkImageData *source)
 
vtkImageData * GetSource ()
 
virtual void SetProjectionMode (int)
 
virtual int GetProjectionMode ()
 
void SetProjectionModeToSimple ()
 
void SetProjectionModeToNonOccluded ()
 
void SetProjectionModeToHug ()
 
virtual void SetHeightOffset (double)
 
virtual double GetHeightOffset ()
 
virtual void SetHeightTolerance (double)
 
virtual double GetHeightTolerance ()
 
virtual void SetMaximumNumberOfLines (vtkIdType)
 
virtual vtkIdType GetMaximumNumberOfLines ()
 

Static Public Member Functions

static vtkProjectedTerrainPathNew ()
 

Protected Member Functions

 vtkProjectedTerrainPath ()
 
 ~vtkProjectedTerrainPath ()
 
virtual int RequestData (vtkInformation *, vtkInformationVector **, vtkInformationVector *)
 
virtual int FillInputPortInformation (int port, vtkInformation *info)
 
void GetImageIndex (double x[3], double loc[2], int ij[2])
 
double GetHeight (double loc[2], int ij[2])
 
void ComputeError (vtkIdType edgeId)
 
void RemoveOcclusions ()
 
void HugTerrain ()
 
void SplitEdge (vtkIdType eId, double t)
 

Protected Attributes

int ProjectionMode
 
double HeightOffset
 
double HeightTolerance
 
vtkIdType MaximumNumberOfLines
 
int Dimensions [3]
 
int Extent [6]
 
double Origin [3]
 
double Spacing [3]
 
vtkDataArray * Heights
 
vtkPoints * Points
 
vtkIdType NumLines
 
vtkPriorityQueue * PositiveLineError
 
vtkPriorityQueue * NegativeLineError
 
vtkEdgeList * EdgeList
 
typedef vtkPolyDataAlgorithm Superclass
 
static int IsTypeOf (const char *type)
 
static vtkProjectedTerrainPathSafeDownCast (vtkObjectBase *o)
 
virtual int IsA (const char *type)
 
vtkProjectedTerrainPathNewInstance () const
 
void PrintSelf (ostream &os, vtkIndent indent)
 
virtual vtkObjectBase * NewInstanceInternal () const
 

Detailed Description

project a polyline onto a terrain

vtkProjectedTerrainPath projects an input polyline onto a terrain. (The terrain is defined by a 2D height image and is the second input to the filter.) The polyline projection is controlled via several modes as follows. 1) Simple mode projects the polyline points onto the terrain, taking into account the height offset instance variable. 2) Non-occluded mode insures that no parts of the polyline are occluded by the terrain (e.g. a line passes through a mountain). This may require recursive subdivision of the polyline. 3) Hug mode insures that the polyine points remain within a constant distance from the surface. This may also require recursive subdivision of the polyline. Note that both non-occluded mode and hug mode also take into account the height offset, so it is possible to create paths that hug terrain a certain distance above it. To use this filter, define two inputs: 1) a polyline, and 2) an image whose scalar values represent a height field. Then specify the mode, and the height offset to use.

An description of the algorithm is as follows. The filter begins by projecting the polyline points to the image (offset by the specified height offset). If the mode is non-occluded or hug, then the maximum error along each line segment is computed and placed into a priority queue. Each line segment is then split at the point of maximum error, and the two new line segments are evaluated for maximum error. This process continues until the line is not occluded by the terrain (non-occluded mode) or satisfies the error on variation from the surface (hug mode). (Note this process is repeated for each polyline in the input. Also, the maximum error is computed in two parts: a maximum positive error and maximum negative error. If the polyline is above the terrain–i.e., the height offset is positive–in non-occluded or hug mode all negative errors are eliminated. If the polyline is below the terrain–i.e., the height offset is negative–in non-occluded or hug mode all positive errors are eliminated.)

Warning
This algorithm requires the entire input image to be in memory, hence it may not work for extremely large images.
The input height image is assumed to be positioned in the x-y plane so the scalar value is the z-coordinate, height value.
A priority queue is used so that the 1) the total number of line segments can be controlled, and 2) the algorithm can terminate when the errors in the queue are less than the specified error tolerance.
See Also
vtkGreedyTerrainDecimation
Tests:
vtkProjectedTerrainPath (Tests)

Definition at line 81 of file vtkProjectedTerrainPath.h.

Member Typedef Documentation

typedef vtkPolyDataAlgorithm vtkProjectedTerrainPath::Superclass

Standard methids for printing and determining type information.

Definition at line 86 of file vtkProjectedTerrainPath.h.

Member Enumeration Documentation

anonymous enum
Enumerator
SIMPLE_PROJECTION 
NONOCCLUDED_PROJECTION 
HUG_PROJECTION 

Definition at line 107 of file vtkProjectedTerrainPath.h.

Constructor & Destructor Documentation

vtkProjectedTerrainPath::vtkProjectedTerrainPath ( )
protected
vtkProjectedTerrainPath::~vtkProjectedTerrainPath ( )
protected

Member Function Documentation

static int vtkProjectedTerrainPath::IsTypeOf ( const char *  type)
static

Standard methids for printing and determining type information.

virtual int vtkProjectedTerrainPath::IsA ( const char *  type)
virtual

Standard methids for printing and determining type information.

static vtkProjectedTerrainPath* vtkProjectedTerrainPath::SafeDownCast ( vtkObjectBase *  o)
static

Standard methids for printing and determining type information.

virtual vtkObjectBase* vtkProjectedTerrainPath::NewInstanceInternal ( ) const
protectedvirtual

Standard methids for printing and determining type information.

vtkProjectedTerrainPath* vtkProjectedTerrainPath::NewInstance ( ) const

Standard methids for printing and determining type information.

void vtkProjectedTerrainPath::PrintSelf ( ostream &  os,
vtkIndent  indent 
)

Standard methids for printing and determining type information.

static vtkProjectedTerrainPath* vtkProjectedTerrainPath::New ( )
static

Instantiate the class.

void vtkProjectedTerrainPath::SetSourceData ( vtkImageData *  source)

Specify the second input (the terrain) onto which the polyline(s) should be projected. Note: This assigns a data object as the input terrain. To establish a pipeline connection, use SetSourceConnection() method.

vtkImageData* vtkProjectedTerrainPath::GetSource ( )

Specify the second input (the terrain) onto which the polyline(s) should be projected. Note: This assigns a data object as the input terrain. To establish a pipeline connection, use SetSourceConnection() method.

void vtkProjectedTerrainPath::SetSourceConnection ( vtkAlgorithmOutput *  algOutput)

Specify the second input (the terrain) onto which the polyline(s) should be projected. Note: vtkImageData* is required

virtual void vtkProjectedTerrainPath::SetProjectionMode ( int  )
virtual

Determine how to control the projection process. Simple projection just projects the original polyline points. Non-occluded projection insures that the polyline does not intersect the terrain surface. Hug projection is similar to non-occulded projection except that produces a path that is nearly parallel to the terrain (within the user specified height tolerance).

virtual int vtkProjectedTerrainPath::GetProjectionMode ( )
virtual

Determine how to control the projection process. Simple projection just projects the original polyline points. Non-occluded projection insures that the polyline does not intersect the terrain surface. Hug projection is similar to non-occulded projection except that produces a path that is nearly parallel to the terrain (within the user specified height tolerance).

void vtkProjectedTerrainPath::SetProjectionModeToSimple ( )
inline

Determine how to control the projection process. Simple projection just projects the original polyline points. Non-occluded projection insures that the polyline does not intersect the terrain surface. Hug projection is similar to non-occulded projection except that produces a path that is nearly parallel to the terrain (within the user specified height tolerance).

Definition at line 119 of file vtkProjectedTerrainPath.h.

void vtkProjectedTerrainPath::SetProjectionModeToNonOccluded ( )
inline

Determine how to control the projection process. Simple projection just projects the original polyline points. Non-occluded projection insures that the polyline does not intersect the terrain surface. Hug projection is similar to non-occulded projection except that produces a path that is nearly parallel to the terrain (within the user specified height tolerance).

Definition at line 121 of file vtkProjectedTerrainPath.h.

void vtkProjectedTerrainPath::SetProjectionModeToHug ( )
inline

Determine how to control the projection process. Simple projection just projects the original polyline points. Non-occluded projection insures that the polyline does not intersect the terrain surface. Hug projection is similar to non-occulded projection except that produces a path that is nearly parallel to the terrain (within the user specified height tolerance).

Definition at line 123 of file vtkProjectedTerrainPath.h.

virtual void vtkProjectedTerrainPath::SetHeightOffset ( double  )
virtual

This is the height above (or below) the terrain that the projected path should be. Positive values indicate distances above the terrain; negative values indicate distances below the terrain.

virtual double vtkProjectedTerrainPath::GetHeightOffset ( )
virtual

This is the height above (or below) the terrain that the projected path should be. Positive values indicate distances above the terrain; negative values indicate distances below the terrain.

virtual void vtkProjectedTerrainPath::SetHeightTolerance ( double  )
virtual

This is the allowable variation in the altitude of the path with respect to the variation in the terrain. It only comes into play if the hug projection mode is enabled.

virtual double vtkProjectedTerrainPath::GetHeightTolerance ( )
virtual

This is the allowable variation in the altitude of the path with respect to the variation in the terrain. It only comes into play if the hug projection mode is enabled.

virtual void vtkProjectedTerrainPath::SetMaximumNumberOfLines ( vtkIdType  )
virtual

This instance variable can be used to limit the total number of line segments created during subdivision. Note that the number of input line segments will be the minimum number that cab be output.

virtual vtkIdType vtkProjectedTerrainPath::GetMaximumNumberOfLines ( )
virtual

This instance variable can be used to limit the total number of line segments created during subdivision. Note that the number of input line segments will be the minimum number that cab be output.

virtual int vtkProjectedTerrainPath::RequestData ( vtkInformation *  ,
vtkInformationVector **  ,
vtkInformationVector *   
)
protectedvirtual
virtual int vtkProjectedTerrainPath::FillInputPortInformation ( int  port,
vtkInformation *  info 
)
protectedvirtual
void vtkProjectedTerrainPath::GetImageIndex ( double  x[3],
double  loc[2],
int  ij[2] 
)
protected
double vtkProjectedTerrainPath::GetHeight ( double  loc[2],
int  ij[2] 
)
protected
void vtkProjectedTerrainPath::ComputeError ( vtkIdType  edgeId)
protected
void vtkProjectedTerrainPath::RemoveOcclusions ( )
protected
void vtkProjectedTerrainPath::HugTerrain ( )
protected
void vtkProjectedTerrainPath::SplitEdge ( vtkIdType  eId,
double  t 
)
protected

Member Data Documentation

int vtkProjectedTerrainPath::ProjectionMode
protected

Definition at line 168 of file vtkProjectedTerrainPath.h.

double vtkProjectedTerrainPath::HeightOffset
protected

Definition at line 169 of file vtkProjectedTerrainPath.h.

double vtkProjectedTerrainPath::HeightTolerance
protected

Definition at line 170 of file vtkProjectedTerrainPath.h.

vtkIdType vtkProjectedTerrainPath::MaximumNumberOfLines
protected

Definition at line 171 of file vtkProjectedTerrainPath.h.

int vtkProjectedTerrainPath::Dimensions[3]
protected

Definition at line 174 of file vtkProjectedTerrainPath.h.

int vtkProjectedTerrainPath::Extent[6]
protected

Definition at line 175 of file vtkProjectedTerrainPath.h.

double vtkProjectedTerrainPath::Origin[3]
protected

Definition at line 176 of file vtkProjectedTerrainPath.h.

double vtkProjectedTerrainPath::Spacing[3]
protected

Definition at line 177 of file vtkProjectedTerrainPath.h.

vtkDataArray* vtkProjectedTerrainPath::Heights
protected

Definition at line 178 of file vtkProjectedTerrainPath.h.

vtkPoints* vtkProjectedTerrainPath::Points
protected

Definition at line 179 of file vtkProjectedTerrainPath.h.

vtkIdType vtkProjectedTerrainPath::NumLines
protected

Definition at line 180 of file vtkProjectedTerrainPath.h.

vtkPriorityQueue* vtkProjectedTerrainPath::PositiveLineError
protected

Definition at line 184 of file vtkProjectedTerrainPath.h.

vtkPriorityQueue* vtkProjectedTerrainPath::NegativeLineError
protected

Definition at line 185 of file vtkProjectedTerrainPath.h.

vtkEdgeList* vtkProjectedTerrainPath::EdgeList
protected

Definition at line 188 of file vtkProjectedTerrainPath.h.


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