geos::operation::overlayng::ElevationModel Class Reference

A simple elevation model used to populate missing Z values in overlay results. More...

#include <ElevationModel.h>

Collaboration diagram for geos::operation::overlayng::ElevationModel:

Classes
class	ElevationCell

Public Member Functions
	ElevationModel (const geom::Envelope &extent, int numCellX, int numCellY)
void	add (const geom::Geometry &geom)
double	getZ (double x, double y)
void	populateZ (geom::Geometry &geom)
	Computes Z values for any missing Z values in a geometry, using the computed model. More...

Static Public Member Functions
static std::unique_ptr< ElevationModel >	create (const geom::Geometry &geom1, const geom::Geometry &geom2)
static std::unique_ptr< ElevationModel >	create (const geom::Geometry &geom1)

Protected Member Functions
void	add (double x, double y, double z)

Private Member Functions
void	init ()
ElevationCell &	getCell (double x, double y)
int	getCellOffset (int ix, int iy)

Private Attributes
geom::Envelope	extent
int	numCellX
int	numCellY
double	cellSizeX
double	cellSizeY
std::vector< ElevationCell >	cells
bool	isInitialized = false
bool	hasZValue = false
double	averageZ = DoubleNotANumber

Static Private Attributes
static const int	DEFAULT_CELL_NUM

Detailed Description

A simple elevation model used to populate missing Z values in overlay results.

The model divides the extent of the input geometry(s) into an NxM grid. The default grid size is 3x3. If the input has no extent in the X or Y dimension, that dimension is given grid size 1. The elevation of each grid cell is computed as the average of the Z values of the input vertices in that cell (if any). If a cell has no input vertices within it, it is assigned the average elevation over all cells.

If no input vertices have Z values, the model does not assign a Z value.

The elevation of an arbitrary location is determined as the Z value of the nearest grid cell.

An elevation model can be used to populate missing Z values in an overlay result geometry.

Author

Martin Davis

Definition at line 65 of file ElevationModel.h.

Constructor & Destructor Documentation

geos::operation::overlayng::ElevationModel::ElevationModel	(	const geom::Envelope &	extent,
		int	numCellX,
		int	numCellY
	)

Member Function Documentation

void geos::operation::overlayng::ElevationModel::add ( double  x, double  y, double  z  )

protected

void geos::operation::overlayng::ElevationModel::add

(

const geom::Geometry &

geom

)

static std::unique_ptr<ElevationModel> geos::operation::overlayng::ElevationModel::create ( const geom::Geometry &  geom1, const geom::Geometry &  geom2  )

static

static std::unique_ptr<ElevationModel> geos::operation::overlayng::ElevationModel::create ( const geom::Geometry &  geom1 )

static

ElevationCell& geos::operation::overlayng::ElevationModel::getCell ( double  x, double  y  )

private

int geos::operation::overlayng::ElevationModel::getCellOffset ( int  ix, int  iy  )

inlineprivate

Definition at line 118 of file ElevationModel.h.

double geos::operation::overlayng::ElevationModel::getZ	(	double	x,
		double	y
	)

Gets the model Z value at a given location. If the location lies outside the model grid extent, this returns the Z value of the nearest grid cell. If the model has no elevation computed (i.e. due to empty input), the value is returned as a double NaN.

Parameters

x	the x ordinate of the location
y	the y ordinate of the location

Returns

the computed model Z value

void geos::operation::overlayng::ElevationModel::init ( )

private

void geos::operation::overlayng::ElevationModel::populateZ

(

geom::Geometry &

geom

)

Computes Z values for any missing Z values in a geometry, using the computed model.

If the model has no Z value, or the geometry coordinate dimension does not include Z, no action is taken.

Parameters

geom	the geometry to elevate

Member Data Documentation

double geos::operation::overlayng::ElevationModel::averageZ = DoubleNotANumber

private

Definition at line 112 of file ElevationModel.h.

std::vector<ElevationCell> geos::operation::overlayng::ElevationModel::cells

private

Definition at line 109 of file ElevationModel.h.

double geos::operation::overlayng::ElevationModel::cellSizeX

private

Definition at line 107 of file ElevationModel.h.

double geos::operation::overlayng::ElevationModel::cellSizeY

private

Definition at line 108 of file ElevationModel.h.

const int geos::operation::overlayng::ElevationModel::DEFAULT_CELL_NUM

staticprivate

Definition at line 103 of file ElevationModel.h.

geom::Envelope geos::operation::overlayng::ElevationModel::extent

private

Definition at line 104 of file ElevationModel.h.

bool geos::operation::overlayng::ElevationModel::hasZValue = false

private

Definition at line 111 of file ElevationModel.h.

bool geos::operation::overlayng::ElevationModel::isInitialized = false

private

Definition at line 110 of file ElevationModel.h.

int geos::operation::overlayng::ElevationModel::numCellX

private

Definition at line 105 of file ElevationModel.h.

int geos::operation::overlayng::ElevationModel::numCellY

private

Definition at line 106 of file ElevationModel.h.

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

• ElevationModel.h