satdump::projection::Projection Class Reference

Extremely generic class to handle projections. More...

#include <projection.h>

Public Types
enum	proj_type_t { PROJ_INVALID = 0 , PROJ_STANDARD = 1 , PROJ_RAYTRACER = 2 , PROJ_THINPLATESPLINE = 3 }

Public Member Functions
proj_type_t	getFwdType ()
	Get forward (Lat/Lon => X/Y) projection type.
proj_type_t	getInvType ()
	Get inverse (X/Y => Lat/Lon) projection type.
bool	init (bool fwd, bool inv)
	Initialize projection, to allow using it to perform the math :-) Disabling doesn't guarantee they won't be initialized internally if required to setup the other! You can use getFwdType/getInvType to check they're not invalid if required.
bool	forward (geodetic::geodetic_coords_t pos, double &x, double &y, bool except=true)
	Run forward (Lat/Lon => X/Y) projection.
bool	inverse (double x, double y, geodetic::geodetic_coords_t &pos, double *otime=nullptr, bool except=true)
	Run forward (X/Y => Lat/Lon) projection.
void	to_json (nlohmann::json &j) const
void	from_json (const nlohmann::json &j)

Public Attributes
int	width = -1
int	height = -1

Friends
void	to_json (nlohmann::json &j, const Projection &v)
void	from_json (const nlohmann::json &j, Projection &v)

Detailed Description

Extremely generic class to handle projections.

This basically abstracts absolutely everything down to a simple class that can be used in 2 lines of codes from a random projection JSON config. By default, all it will do is simply hide the JSON config internally (especially useful to allow manipulating projs in Lua!), but once init() is called, it allows actually performing the projection transform (meant for images).

Do note this is not really intended (in most cases) for high-performance scenarios, such as reprojections.

Member Function Documentation

forward()

bool satdump::projection::Projection::forward	(	geodetic::geodetic_coords_t	pos,
		double &	x,
		double &	y,
		bool	except = true )

Run forward (Lat/Lon => X/Y) projection.

Parameters

pos	output geodetic position
x	pixel position
y	pixel position
except	if false, doesn't throw exceptions

Returns

true on error

getFwdType()

proj_type_t satdump::projection::Projection::getFwdType ( )

inline

Get forward (Lat/Lon => X/Y) projection type.

Returns

projection type

getInvType()

proj_type_t satdump::projection::Projection::getInvType ( )

inline

Get inverse (X/Y => Lat/Lon) projection type.

Returns

projection type

init()

bool satdump::projection::Projection::init	(	bool	fwd,
		bool	inv )

Initialize projection, to allow using it to perform the math :-) Disabling doesn't guarantee they won't be initialized internally if required to setup the other! You can use getFwdType/getInvType to check they're not invalid if required.

Parameters

fwd	init forward proj
inv	init inverse proj

Returns

true if valid

inverse()

bool satdump::projection::Projection::inverse	(	double	x,
		double	y,
		geodetic::geodetic_coords_t &	pos,
		double *	otime = nullptr,
		bool	except = true )

Run forward (X/Y => Lat/Lon) projection.

Parameters

x	pixel position
y	pixel position
pos	output geodetic position
otime	pixel timestamp, MUST be set to -1 before passing to this function. No guarantee the underlaying projection supports this, must be checked before use
except	if false, doesn't throw exceptions

Returns

true on error

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

• src-core/projection/projection.h
• src-core/projection/projection.cpp