Detailed Description

A static class to compute various DEM-related parameters (such as shading, view factors, etc)

#include <DEMAlgorithms.h>

Static Public Member Functions
static Grid2DObject	getHillshade (const DEMObject &dem, const double &elev, const double &azimuth)
	Computes the hillshade for the dem This "fake illumination" method is used to better show the relief on maps. More...

static double	getHorizon (const DEMObject &dem, const size_t &ix1, const size_t &iy1, const double &bearing)
	Returns the tangente of the horizon from a given point looking toward a given bearing. More...

static double	getHorizon (const DEMObject &dem, Coords point, const double &bearing)
	Returns the tangente of the horizon from a given point looking toward a given bearing. More...

static std::vector< std::pair< double, double > >	getHorizonScan (const DEMObject &dem, Coords point, const double &increment)
	Returns the horizon from a given point looking 360 degrees around by increments. If the provided point does not fit within the provided DEM, an empty result set is returned. More...

static std::map< std::string, std::vector< std::pair< double, double > > >	readHorizonScan (const std::string &where, const std::string &filename)
	Read the horizons from a given set of points looking 360 degrees around provided in a file. More...

static double	getHorizon (const std::vector< std::pair< double, double > > &horizon, const double &azimuth)
	Linearly interpolate the horizon height for any given azimuth given a set of (azimuth, elevation) points. More...

static void	writeHorizons (const std::map< std::string, std::vector< std::pair< double, double > > > &horizon, const std::string &filename)
	Write to a file the horizons from a given set of points looking 360 degrees around. More...

static double	getCellSkyViewFactor (const DEMObject &dem, const size_t &ii, const size_t &jj)
	Compute the sky view factors for the terrain radiation based on the DEM. This is inspired (ie with some changes) by Manners, J., S. B. Vosper, and N. Roberts, "Radiative transfer over resolved topographic features for high‐resolution weather prediction", Quarterly journal of the royal meteorological society, 138.664, pp720-733, 2012. More...

Member Function Documentation

◆ getCellSkyViewFactor()

double mio::DEMAlgorithms::getCellSkyViewFactor	(	const DEMObject &	dem,
		const size_t &	ii,
		const size_t &	jj
	)

static

Compute the sky view factors for the terrain radiation based on the DEM. This is inspired (ie with some changes) by Manners, J., S. B. Vosper, and N. Roberts, "Radiative transfer over resolved topographic features for high‐resolution weather prediction", Quarterly journal of the royal meteorological society, 138.664, pp720-733, 2012.

Parameters

[in]	dem	DEM to work with
[in]	ii	x coordinate of the cell whose view factor should be computed
[in]	jj	y coordinate of the cell whose view factor should be computed

Returns: sky view factor

◆ getHillshade()

Grid2DObject mio::DEMAlgorithms::getHillshade	(	const DEMObject &	dem,
		const double &	elev,
		const double &	azimuth
	)

static

Computes the hillshade for the dem This "fake illumination" method is used to better show the relief on maps.

Parameters

[in]	dem	DEM to work with
[in]	elev	elevation (in degrees) of the source of light
[in]	azimuth	azimuth (in degrees) of the source of light

Returns: hillshade grid that containing the illumination

◆ getHorizon() [1/3]

double mio::DEMAlgorithms::getHorizon	(	const DEMObject &	dem,
		const size_t &	ix1,
		const size_t &	iy1,
		const double &	bearing
	)

static

Returns the tangente of the horizon from a given point looking toward a given bearing.

Parameters

[in]	dem	DEM to work with
[in]	ix1	x index of the origin point
[in]	iy1	y index of the origin point
[in]	bearing	direction given by a compass bearing

Returns: tangente of angle above the horizontal (in deg) or IOUtils::nodata if the point (ix1, iy1) does not fit within the provided DEM

◆ getHorizon() [2/3]

double mio::DEMAlgorithms::getHorizon	(	const DEMObject &	dem,
		Coords	point,
		const double &	bearing
	)

static

Returns the tangente of the horizon from a given point looking toward a given bearing.

Parameters

[in]	dem	DEM to work with
[in]	point	the origin point
[in]	bearing	direction given by a compass bearing

Returns: tangente of angle above the horizontal (in deg) or IOUtils::nodata if the provided point does not fir within the provided DEM

◆ getHorizon() [3/3]

double mio::DEMAlgorithms::getHorizon	(	const std::vector< std::pair< double, double > > &	horizon,
		const double &	azimuth
	)

static

Linearly interpolate the horizon height for any given azimuth given a set of (azimuth, elevation) points.

Parameters

[in]	horizon	a set of (azimuth, elevation) coordinates defining the horizon
[in]	azimuth	the azimuth where to perform the interpolation

Returns: the interpolated elevation for the provided azimuth

◆ getHorizonScan()

std::vector< std::pair< double, double > > mio::DEMAlgorithms::getHorizonScan	(	const DEMObject &	dem,
		Coords	point,
		const double &	increment
	)

static

Returns the horizon from a given point looking 360 degrees around by increments. If the provided point does not fit within the provided DEM, an empty result set is returned.

Parameters

[in]	dem	DEM to work with
[in]	point	the origin point
[in]	increment	to the bearing between two angles

Returns: horizon vector of heights as a function of azimuth

◆ readHorizonScan()

std::map< std::string, std::vector< std::pair< double, double > > > mio::DEMAlgorithms::readHorizonScan	(	const std::string &	where,
		const std::string &	filename
	)

static

Read the horizons from a given set of points looking 360 degrees around provided in a file.

The file containing the horizons is made of any number of lines with the following structure: {stationID} {azimuth} {elevation} where the azimuth is given in degrees North (as read from a compass) and the elevation as degrees above the horizontal. For example:

STB2 0 2
STB2 210 18
WFJ 180 5
WFJ 130 10
STB2 180 25

Parameters

[in]	where	Description of the caller to be used in error messages, such as 'Filter::shade'
[in]	filename	the file and path containing the horizon

Returns: a map containing for each stationID the horizon vector of heights as a function of azimuth

◆ writeHorizons()

void mio::DEMAlgorithms::writeHorizons	(	const std::map< std::string, std::vector< std::pair< double, double > > > &	horizon,
		const std::string &	filename
	)

static

Write to a file the horizons from a given set of points looking 360 degrees around.

The file containing the horizons is made of any number of lines with the following structure: {stationID} {azimuth} {elevation} where the azimuth is given in degrees North (as read from a compass) and the elevation as degrees above the horizontal. For example:

STB2 0 2
STB2 210 18
WFJ 180 5
WFJ 130 10
STB2 180 25

Parameters

[in]	horizon	a map of vectors of (azimuth, elevation) coordinates defining the horizon, per stationID
[in]	filename	the file and path where to write the horizon

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

Detailed Description

Static Public Member Functions

Member Function Documentation

◆ getCellSkyViewFactor()

◆ getHillshade()

◆ getHorizon() [1/3]

◆ getHorizon() [2/3]

◆ getHorizon() [3/3]

◆ getHorizonScan()

◆ readHorizonScan()

◆ writeHorizons()