WatershedAnalysis Class Reference

A heightfield flow routing structure. More...

#include <watershed.h>

Inheritance diagram for WatershedAnalysis:

Public Member Functions
	WatershedAnalysis (const ScalarField2 &, bool=false)
	Create the heightfield flow routing structure.
QVector< QPoint >	Watershed (const QPoint &) const
	Compute the watershed of the argument point.
QVector< QPoint >	River (const QPoint &) const
	Compute the longest river flowing to the argument point.
QVector< QPoint >	River (const QPoint &, const QPoint &) const
	Compute the river connecting two points.
double	WatershedArea (const QPoint &) const
	Compute the drainage area of the watershed flowing through the argument point.
double	RiverLength (const QPoint &) const
	Compute the length of the longest river flowing to the argument point.
double	RiverLength (const QVector< QPoint >) const
	Compute the river length of a set of points.
void	Draw (QGraphicsScene &, int, const QPen &=QPen(), const QBrush &=QBrush()) const
	Draw a rectangle.
void	DrawWatershed (QGraphicsScene &, const QVector< QPoint > &, const QPen &=QPen(), const QBrush &=QBrush()) const
	Draw the watershed.
double	BreachingCost () const
	Compute the breaching cost.
double	FillingCost () const
	Compute the filling cost.
double	Flow (int, int) const
	Compute flow.

Protected Attributes
HeightField	hf
	Reference to heightfield.
ScalarField2	area
	Drainage area.
Array2I	upstream
	Upstream topology.
Array2I	downstream
	Downstream topology.

Detailed Description

A heightfield flow routing structure.

This class implements a structure that stores the drainage area and the corresponding upstream and downstream directed graphs.

It is needed to compute the watersheds.

Constructor & Destructor Documentation

WatershedAnalysis()

WatershedAnalysis::WatershedAnalysis ( const ScalarField2 & s, bool steep = false )

explicit

Create the heightfield flow routing structure.

Parameters

s	The heightfield.
steep	Flag, set to true if we rely on the steepest slope, false for multiple convergent and divergent flows.

Member Function Documentation

BreachingCost()

double WatershedAnalysis::BreachingCost

(

)

const

Compute the breaching cost.

This function computes the volume of bedrock removed by the breaching process. It then converts it into an average height (like precipitation) by dividing by the area of the terrain.

Results are in meters per squared-meter.

HeightField hf;
WatershedAnalysis a(hf);
double e = 1000.0*a.BreachingCost(); // Multiply by 1000 to get cost in millimeters per squared meter.

Draw()

void WatershedAnalysis::Draw	(	QGraphicsScene &	scene,
		int	n,
		const QPen &	pen = QPen(),
		const QBrush &	brush = QBrush() ) const

Draw a rectangle.

Parameters

scene	Graphics scene.
pen	The pen.
n	Upstream or downstream.
brush	The brush, should the box be filled.

DrawWatershed()

void WatershedAnalysis::DrawWatershed	(	QGraphicsScene &	scene,
		const QVector< QPoint > &	w,
		const QPen &	pen = QPen(),
		const QBrush &	brush = QBrush() ) const

Draw the watershed.

Parameters

scene	Graphics scene.
w	Set of watershed points.
pen	The pen.
brush	The brush, should the box be filled.

FillingCost()

double WatershedAnalysis::FillingCost

(

)

const

Compute the filling cost.

See also

WatershedAnalysis::BreachingCost() const

Flow()

double WatershedAnalysis::Flow	(	int	i,
		int	j ) const

Compute flow.

Uses a power law to compute flow from drainage area.

River() [1/2]

QVector< QPoint > WatershedAnalysis::River

(

const QPoint &

p

)

const

Compute the longest river flowing to the argument point.

Parameters

p

Point.

River() [2/2]

QVector< QPoint > WatershedAnalysis::River	(	const QPoint &	a,
		const QPoint &	b ) const

Compute the river connecting two points.

The function returns the river flowing to a pit if no connecting river path exists.

Parameters

a,b	Starting (source) and ending (outlet) points.

RiverLength() [1/2]

double WatershedAnalysis::RiverLength

(

const QPoint &

p

)

const

Compute the length of the longest river flowing to the argument point.

See also

WatershedAnalysis::River

Parameters

p

Point.

RiverLength() [2/2]

double WatershedAnalysis::RiverLength

(

const QVector< QPoint >

river

)

const

Compute the river length of a set of points.

Parameters

river

Set of points defining the river.

Watershed()

QVector< QPoint > WatershedAnalysis::Watershed

(

const QPoint &

p

)

const

Compute the watershed of the argument point.

Parameters

p

Point.

WatershedArea()

double WatershedAnalysis::WatershedArea

(

const QPoint &

p

)

const

Compute the drainage area of the watershed flowing through the argument point.

See also

WatershedAnalysis::Watershed

Parameters

p

Point.