gridpp Namespace Reference

Functions
vec2	bilinear (const Grid &igrid, const Grid &ogrid, const vec2 ivalues)
	Bilinear downscaling grid to grid. More...
vec	bilinear (const Grid &igrid, const Points &opoints, const vec2 ivalues)
	Bilinear downscaling grid to points. More...
float	dewpoint (float temperature, float relative_humidity)
	Calculate dewpoint temperature from temperature and relative humidity. More...
vec	dewpoint (const vec &temperature, const vec &relative_humidity)
	Vector version of dewpoint calculation. More...
vec2	fill (const Grid &igrid, const vec2 &input, const Points &points, const vec &radii, float value, bool outside)
	Fill in values inside or outside a set of circles. More...
vec	get_neighbourhood_thresholds (const vec2 &input, int num_thresholds)
	Calculate appropriate approximation thresholds for neighbourhood quantile. More...
vec	get_neighbourhood_thresholds (const vec3 &input, int num_thresholds)
	Calculate appropriate approximation thresholds for neighbourhood quantile. More...
Statistic	get_statistic (std::string name)
	Convert name of a statistic enum. More...
void	initialize_omp ()
	Sets the number of OpenMP threads to 1 if OMP_NUM_THREADS undefined. More...
vec2	nearest (const Grid &igrid, const Grid &ogrid, const vec2 ivalues)
	Nearest neighbour dowscaling grid to grid. More...
vec	nearest (const Grid &igrid, const Points &opoints, const vec2 ivalues)
	Nearest neighbour dowscaling grid to point. More...
vec2	nearest (const Grid &igrid, const Points &opoints, const vec3 ivalues)
vec2	neighbourhood (const vec2 &input, int radius, Statistic statistic)
	Spatial neighbourhood filter. More...
vec2	neighbourhood_brute_force (const vec2 &input, int radius, Statistic statistic)
	Spatial neighbourhood filter without any shortcuts. More...
vec2	neighbourhood_ens (const vec3 &input, int radius, Statistic statistic)
	Neighbourhood filter in space and across ensemble members. More...
vec2	neighbourhood_quantile (const vec2 &input, float quantile, int radius)
	Spatial neighbourhood filter. More...
vec2	neighbourhood_quantile_ens (const vec3 &input, float quantile, int radius)
	Neighbourhood filter in space and across ensemble members. More...
vec2	neighbourhood_quantile_ens_fast (const vec3 &input, float quantile, int radius, const vec &thresholds)
	Approximate neighbourhood filter space and across members for quantile operation. More...
vec2	neighbourhood_quantile_fast (const vec2 &input, float quantile, int radius, const vec &thresholds)
	Approximate spatial neighbourhood filter for quantile operation. More...
vec2	optimal_interpolation (const gridpp::Grid &bgrid, const vec2 &background, const gridpp::Points &points, const vec &pobs, const vec &pratios, const vec &pbackground, const gridpp::StructureFunction &structure, int max_points)
	Optimal interpolation for a deterministic field. More...
vec3	optimal_interpolation_ensi (const gridpp::Grid &bgrid, const vec3 &input, const gridpp::Points &points, const vec &pobs, const vec &psigmas, const vec2 &pbackground, const gridpp::StructureFunction &structure, int max_points)
	Optimal interpolation using a structure function based on an ensemble See Lussana et al 2019 (DOI: 10.1002/qj.3646) More...
vec2	optimal_interpolation_transform (const gridpp::Grid &bgrid, const vec2 &background, float bsigma, const gridpp::Points &points, const vec &pobs, const vec &psigma, const vec &pbackground, const gridpp::StructureFunction &structure, int max_points, const gridpp::Transform &transform)
float	pressure (float ielev, float oelev, float ipressure, float itemperature=288.15)
	Calculate pressure at a new elevation. More...
float	qnh (float pressure, float altitude)
	Diagnose QNH from pressure and altitude. More...
vec	qnh (const vec &pressure, const vec &altitude)
	Vector version of QNH calculation. More...
vec2	quantile_mapping (const vec2 &input, const vec &x, const vec &y, gridpp::Extrapolation policy)
	Quantile mapping of 2D grid using a constant quantile map. More...
vec	quantile_mapping (const vec &input, const vec &x, const vec &y, gridpp::Extrapolation policy)
	Quantile mapping of a vector of value. More...
float	quantile_mapping (float input, const vec &ref, const vec &fcst, gridpp::Extrapolation policy)
	Quantile mapping of a single value. More...
float	relative_humidity (float temperature, float dewpoint)
	Calculate relative humidity from temperature and dewpoint temperature. More...
void	set_omp_threads (int num)
	Set the number of OpenMP threads to use. More...
vec2	simple_gradient (const Grid &igrid, const Grid &ogrid, const vec2 ivalues, float elev_gradient)
vec	simple_gradient (const Grid &igrid, const Points &opoints, const vec2 ivalues, float elev_gradient)
std::string	version ()
	The gridpp version. More...
float	wetbulb (float temperature, float pressure, float relative_humidity)
	Calculate wetbulb temperature from temperature, pressure, and relative humidity. More...
float	wind_speed (float xwind, float ywind)
	Diagnose wind speed from its components. More...
vec	wind_speed (const vec &xwind, const vec &ywind)
vec2	wind_speed (const vec2 &xwind, const vec2 &ywind)

Enumerations
enum	Extrapolation { OneToOne = 0, MeanSlope = 10, NearestSlope = 20, Zero = 30 }
	Methods for extrapolating outside a curve. More...
enum	Statistic {   Mean = 0, Min = 10, Median = 20, Max = 30,   Quantile = 40, Std = 50, Variance = 60, Sum = 70,   Unknown = -1 }
	Statistical operations to reduce a vector to a scalar. More...

Classes
class	BarnesStructure
	Simple structure function based on distance, elevation, and land area fraction. More...
class	BoxCox
class	CressmanStructure
	Simple structure function based on distance, elevation, and land area fraction. More...
class	CrossValidation
class	Grid
	Represents a 2D grid of locations and their metadata. More...
class	Identity
class	KDTree
	Helper class for Grid and Points. More...
class	Log
class	Point
class	Points
	Represents a vector of locations and their metadata. More...
class	StructureFunction
	Covariance structure function. More...
class	Transform

Namespaces
	util
	Helper functions.

Variables
static const float	MV = NAN
static const float	MV_CML = -999
static const float	pi = 3.14159265
static double	radius_earth = 6.37e6

Enumeration Type Documentation

Extrapolation

enum gridpp::Extrapolation

Methods for extrapolating outside a curve.

Enumerator
OneToOne	Continue past the end-points using a slope of 1.
MeanSlope	Continue past the end-points using the mean slope of the curve.
NearestSlope	Continue past the end-points using the slope of the two lowermost or uppermost points in the curve.
Zero	Continue past the end-points using a slope of 0.

Statistic

enum gridpp::Statistic

Statistical operations to reduce a vector to a scalar.

Enumerator
Mean	Mean of values.
Min	Minimum of values.
Median	Mean of values.
Max	Maximum of values.
Quantile	A quantile from values.
Std	Standard deviation of values.
Variance	Population variance of values.
Sum	Sum of values.
Unknown	Unknown statistic.

Function Documentation

bilinear() [1/2]

vec2 gridpp::bilinear	(	const Grid &	igrid,
		const Grid &	ogrid,
		const vec2	ivalues
	)

Bilinear downscaling grid to grid.

Parameters

igrid	Input grid
ogrid	Output grid to downscale to
ivalues	2D vector of values on the input grid

Returns

Values on the output grid

bilinear() [2/2]

vec gridpp::bilinear	(	const Grid &	igrid,
		const Points &	opoints,
		const vec2	ivalues
	)

Bilinear downscaling grid to points.

Parameters

igrid	Input grid
ogrid	Output points to downscale to
ivalues	2D vector of values on the input grid

Returns

Values for the output points

dewpoint() [1/2]

float gridpp::dewpoint	(	float	temperature,
		float	relative_humidity
	)

Calculate dewpoint temperature from temperature and relative humidity.

Parameters

temperature	Temperature [K]
relative_humidity	Relative humidity [1]

Returns

Dewpoint temperature [K]

dewpoint() [2/2]

vec gridpp::dewpoint	(	const vec &	temperature,
		const vec &	relative_humidity
	)

Vector version of dewpoint calculation.

Parameters

temperature	Temperatures [K]
relative_humidity	Relative humidities [1]

Returns

Dewpoint temperatures [K]

fill()

vec2 gridpp::fill	(	const Grid &	igrid,
		const vec2 &	input,
		const Points &	points,
		const vec &	radii,
		float	value,
		bool	outside
	)

Fill in values inside or outside a set of circles.

Parameters

input	Deterministic values with dimensions Y, X
radiii	Circle radii for each point
value	Fill in this value
outside	if True, fill outside circles, if False, fill inside circles

get_neighbourhood_thresholds() [1/2]

vec gridpp::get_neighbourhood_thresholds	(	const vec2 &	input,
		int	num_thresholds
	)

Calculate appropriate approximation thresholds for neighbourhood quantile.

Parameters

input	2D grid of values
num_thresholds	Number of thresholds

get_neighbourhood_thresholds() [2/2]

vec gridpp::get_neighbourhood_thresholds	(	const vec3 &	input,
		int	num_thresholds
	)

Calculate appropriate approximation thresholds for neighbourhood quantile.

Parameters

input	3D grid of values
num_thresholds	Number of thresholds

get_statistic()

gridpp::Statistic gridpp::get_statistic

(

std::string

name

)

Convert name of a statistic enum.

initialize_omp()

void gridpp::initialize_omp

(

)

Sets the number of OpenMP threads to 1 if OMP_NUM_THREADS undefined.

nearest() [1/3]

vec2 gridpp::nearest	(	const Grid &	igrid,
		const Grid &	ogrid,
		const vec2	ivalues
	)

Nearest neighbour dowscaling grid to grid.

Parameters

igrid	Input grid
ogrid	Output grid to downscale to
ivalues	2D vector of values on the input grid

Returns

Values on the output grid

nearest() [2/3]

vec gridpp::nearest	(	const Grid &	igrid,
		const Points &	opoints,
		const vec2	ivalues
	)

Nearest neighbour dowscaling grid to point.

Parameters

igrid	Input grid
ogrid	Output points to downscale to
ivalues	2D vector of values on the input grid

Returns

Values for the output points

nearest() [3/3]

vec2 gridpp::nearest	(	const Grid &	igrid,
		const Points &	opoints,
		const vec3	ivalues
	)

neighbourhood()

vec2 gridpp::neighbourhood	(	const vec2 &	input,
		int	radius,
		gridpp::Statistic	statistic
	)

Spatial neighbourhood filter.

Parameters

input	2D grid of values
radius	Filter radius in number of gridpoints
statistic	Statistic to compute

neighbourhood_brute_force()

vec2 gridpp::neighbourhood_brute_force	(	const vec2 &	input,
		int	radius,
		gridpp::Statistic	statistic
	)

Spatial neighbourhood filter without any shortcuts.

This is quite slow and is only useful for testing.

Parameters

input	2D grid of values
radius	Filter radius in number of gridpoints
operation	one of min, mean, median, max

neighbourhood_ens()

vec2 gridpp::neighbourhood_ens	(	const vec3 &	input,
		int	radius,
		gridpp::Statistic	statistic
	)

Neighbourhood filter in space and across ensemble members.

Parameters

input	3D vector with dimensions (Y, X, ensemble)
radius	Filter radius in number of gridpoints
statistic	Statistic to compute

neighbourhood_quantile()

vec2 gridpp::neighbourhood_quantile	(	const vec2 &	input,
		float	quantile,
		int	radius
	)

Spatial neighbourhood filter.

An exact but slow algorithm.

Parameters

input	2D grid of values
radius	Filter radius in number of gridpoints
quantile	Quantile to calculate for (between 0 and 1)

neighbourhood_quantile_ens()

vec2 gridpp::neighbourhood_quantile_ens	(	const vec3 &	input,
		float	quantile,
		int	radius
	)

Neighbourhood filter in space and across ensemble members.

An exampt but slow algorithm.

Parameters

input	3D grid of values
radius	Filter radius in number of gridpoints
quantile	Quantile to calculate for (between 0 and 1)

neighbourhood_quantile_ens_fast()

vec2 gridpp::neighbourhood_quantile_ens_fast	(	const vec3 &	input,
		float	quantile,
		int	radius,
		const vec &	thresholds
	)

Approximate neighbourhood filter space and across members for quantile operation.

Parameters

input	3D vector with dimensions (Y, X, ensemble)
quantile	Quantile to compute (between 0 and 1)
radius	Filter radius in number of gridpoints
thresholds	Vector of thresholds to use to approximate value

neighbourhood_quantile_fast()

vec2 gridpp::neighbourhood_quantile_fast	(	const vec2 &	input,
		float	quantile,
		int	radius,
		const vec &	thresholds
	)

Approximate spatial neighbourhood filter for quantile operation.

Parameters

input	2D grid of values
quantile	Quantile to compute (between 0 and 1)
radius	Filter radius in number of gridpoints
thresholds	Vector of thresholds to use to approximate value

optimal_interpolation()

vec2 gridpp::optimal_interpolation	(	const gridpp::Grid &	bgrid,
		const vec2 &	background,
		const gridpp::Points &	points,
		const vec &	pobs,
		const vec &	pratios,
		const vec &	pbackground,
		const gridpp::StructureFunction &	structure,
		int	max_points
	)

Optimal interpolation for a deterministic field.

Parameters

bgrid	Grid of background field
background	2D field of background values
points	Points of observations
pobs	Vector of observations
pratios	Vector of ratio of observation error variance to background variance
pbackground	Background with observation operator
structure	Structure function
max_points	Maximum number of observations to use inside localization zone; Use 0 to disable

optimal_interpolation_ensi()

vec3 gridpp::optimal_interpolation_ensi	(	const gridpp::Grid &	bgrid,
		const vec3 &	input,
		const gridpp::Points &	points,
		const vec &	pobs,
		const vec &	psigmas,
		const vec2 &	pbackground,
		const gridpp::StructureFunction &	structure,
		int	max_points
	)

Optimal interpolation using a structure function based on an ensemble See Lussana et al 2019 (DOI: 10.1002/qj.3646)

Parameters

input	3D field of background values (Y, X, E)
bgrid	grid corresponding to input
pobs	vector of observations
pci	vector of ci values
points	observation points

optimal_interpolation_transform()

vec2 gridpp::optimal_interpolation_transform	(	const gridpp::Grid &	bgrid,
		const vec2 &	background,
		float	bsigma,
		const gridpp::Points &	points,
		const vec &	pobs,
		const vec &	psigma,
		const vec &	pbackground,
		const gridpp::StructureFunction &	structure,
		int	max_points,
		const gridpp::Transform &	transform
	)

pressure()

float gridpp::pressure	(	float	ielev,
		float	oelev,
		float	ipressure,
		float	itemperature = 288.15
	)

Calculate pressure at a new elevation.

Parameters

ielev	Elevation at start point
oelev	Elevation at new point
ipressure	Pressure at start point
itemperature	Temperature at start point

Returns

Pressure at new point

qnh() [1/2]

float gridpp::qnh	(	float	pressure,
		float	altitude
	)

Diagnose QNH from pressure and altitude.

Parameters

pressure	Pressure at point [pa]
altitude	Altitude of point [m]

Returns

QNH [pa]

qnh() [2/2]

vec gridpp::qnh	(	const vec &	pressure,
		const vec &	altitude
	)

Vector version of QNH calculation.

Parameters

pressure	Pressures at points [pa]
altitude	Altitudes of points [m]

Returns

QNH [pa]

quantile_mapping() [1/3]

vec2 gridpp::quantile_mapping	(	const vec2 &	input,
		const vec &	x,
		const vec &	y,
		gridpp::Extrapolation	policy
	)

Quantile mapping of 2D grid using a constant quantile map.

Parameters

input	Values on grid
x	X-axis parameters values
y	Y-axis parameters values
policy	Extrapolation policy

Returns

Quantile-mapped values

quantile_mapping() [2/3]

vec gridpp::quantile_mapping	(	const vec &	input,
		const vec &	x,
		const vec &	y,
		gridpp::Extrapolation	policy
	)

Quantile mapping of a vector of value.

Parameters

input	Input values
x	X-axis parameters values
y	Y-axis parameters values
policy	Extrapolation policy

Returns

Quantile-mapped output values

quantile_mapping() [3/3]

float gridpp::quantile_mapping	(	float	input,
		const vec &	ref,
		const vec &	fcst,
		gridpp::Extrapolation	policy
	)

Quantile mapping of a single value.

Parameters

input	Input value
x	X-axis parameters values
y	Y-axis parameters values
policy	Extrapolation policy

Returns

Quantile-mapped output value

relative_humidity()

float gridpp::relative_humidity	(	float	temperature,
		float	dewpoint
	)

Calculate relative humidity from temperature and dewpoint temperature.

Parameters

temperature	Temperature [K]
dewpoint	Dewpoint temperature [K]

Returns

Relative humidity [1]

set_omp_threads()

void gridpp::set_omp_threads

(

int

num

)

Set the number of OpenMP threads to use.

Overwrides OMP_NUM_THREAD env variable.

simple_gradient() [1/2]

vec2 gridpp::simple_gradient	(	const Grid &	igrid,
		const Grid &	ogrid,
		const vec2	ivalues,
		float	elev_gradient
	)

simple_gradient() [2/2]

vec gridpp::simple_gradient	(	const Grid &	igrid,
		const Points &	opoints,
		const vec2	ivalues,
		float	elev_gradient
	)

version()

std::string gridpp::version

(

)

The gridpp version.

Returns

The gridpp version

wetbulb()

float gridpp::wetbulb	(	float	temperature,
		float	pressure,
		float	relative_humidity
	)

Calculate wetbulb temperature from temperature, pressure, and relative humidity.

Parameters

temperature	Temperature [K]
pressure	Air pressure [pa]
Relative	humidity [1]

Returns

Wetbulb temperature [K]

wind_speed() [1/3]

float gridpp::wind_speed	(	float	xwind,
		float	ywind
	)

Diagnose wind speed from its components.

Parameters

xwind	X-component of wind [any unit]
ywind	Y-component of wind [any unit]

Returns

Wind speed [any unit]

wind_speed() [2/3]

vec gridpp::wind_speed	(	const vec &	xwind,
		const vec &	ywind
	)

wind_speed() [3/3]

vec2 gridpp::wind_speed	(	const vec2 &	xwind,
		const vec2 &	ywind
	)

Variable Documentation

MV

const float gridpp::MV = NAN

static

MV_CML

const float gridpp::MV_CML = -999

static

pi

const float gridpp::pi = 3.14159265

static

radius_earth

double gridpp::radius_earth = 6.37e6

static