This file declares a set of functions that storage engines can call to do geometrical operations. More...

#include "my_inttypes.h"
#include "sql/gis/srid.h"

Classes
struct	rtr_mbr
	In memory representation of a minimum bounding rectangle. More...

Namespaces
namespace	dd
	The version of the current data dictionary table definitions.

Typedefs
typedef struct rtr_mbr	rtr_mbr_t
	In memory representation of a minimum bounding rectangle. More...

Functions
dd::Spatial_reference_system *	fetch_srs (gis::srid_t srid)
	Fetches a copy of the dictionary entry for a spatial reference system. More...

bool	mbr_contain_cmp (const dd::Spatial_reference_system srs, rtr_mbr_t a, rtr_mbr_t *b)
	Checks if one MBR covers another MBR. More...

bool	mbr_equal_cmp (const dd::Spatial_reference_system srs, rtr_mbr_t a, rtr_mbr_t *b)
	Checks if two MBRs are equal. More...

bool	mbr_intersect_cmp (const dd::Spatial_reference_system srs, rtr_mbr_t a, rtr_mbr_t *b)
	Checks if two MBRs intersect each other. More...

bool	mbr_disjoint_cmp (const dd::Spatial_reference_system srs, rtr_mbr_t a, rtr_mbr_t *b)
	Checks if two MBRs are disjoint. More...

bool	mbr_within_cmp (const dd::Spatial_reference_system srs, rtr_mbr_t a, rtr_mbr_t *b)
	Checks if one MBR is covered by another MBR. More...

void	mbr_join (const dd::Spatial_reference_system srs, double a, const double *b, int n_dim)
	Expands an MBR to also cover another MBR. More...

double	mbr_join_area (const dd::Spatial_reference_system srs, const double a, const double *b, int n_dim)
	Computes the combined area of two MBRs. More...

double	compute_area (const dd::Spatial_reference_system srs, const double a, int n_dim)
	Computes the area of an MBR. More...

int	get_mbr_from_store (const dd::Spatial_reference_system srs, const uchar store, uint size, uint n_dims, double mbr, gis::srid_t srid)
	Computes the MBR of a geometry. More...

double	rtree_area_increase (const dd::Spatial_reference_system srs, const uchar mbr_a, const uchar mbr_b, int mbr_len, double ab_area)
	Computes the extra area covered if an MBR is expanded to cover another MBR. More...

double	rtree_area_overlapping (const dd::Spatial_reference_system srs, const uchar mbr_a, const uchar *mbr_b, int mbr_len)
	Calculates the overlapping area between two MBRs. More...

Detailed Description

This file declares a set of functions that storage engines can call to do geometrical operations.

Typedef Documentation

◆ rtr_mbr_t

typedef struct rtr_mbr rtr_mbr_t

In memory representation of a minimum bounding rectangle.

Function Documentation

◆ compute_area()

double compute_area	(	const dd::Spatial_reference_system *	srs,
		const double *	a,
		int	n_dim
	)

Computes the area of an MBR.

Note: The function takes a dimension parameter, but currently only supports 2d MBRs.

Parameters

[in]	srs	Spatial reference system.
[in]	a	The MBR.
[in]	n_dim	Number of dimensions. Must be 2.

Returns: Are of the MBR.

◆ fetch_srs()

dd::Spatial_reference_system * fetch_srs ( gis::srid_t srid )

Fetches a copy of the dictionary entry for a spatial reference system.

Spatial reference dictionary cache objects have a limited lifetime, typically until the end of a transaction. This function returns a clone of the dictionary object so that it is valid also after the transaction has ended. This is necessary since InnoDB may do index operations after the transaction has ended.

Parameters

[in] srid The spatial reference system ID to look up.

Returns: The spatial reference system dictionary entry, or nullptr.

◆ get_mbr_from_store()

int get_mbr_from_store	(	const dd::Spatial_reference_system *	srs,
		const uchar *	store,
		uint	size,
		uint	n_dims,
		double *	mbr,
		gis::srid_t *	srid
	)

Computes the MBR of a geometry.

If the geometry is empty, a box that covers the entire domain is returned.

The geometry is expected to be on the storage format (SRID + WKB). The caller is expected to provide an output buffer that is large enough.

Note: The function takes a dimension parameter, but currently only supports 2d MBRs.

The SRID of the SRS parameter must match the SRID stored in the first four bytes of the geometry string.

Parameters

[in]	srs	Spatial reference system.
[in]	store	The geometry.
[in]	size	Number of bytes in the geometry string.
[in]	n_dims	Number of dimensions. Must be 2.
[out]	mbr	The computed MBR.
[out]	srid	SRID of the geometry

Return values

0	The geometry is valid.
-1	The geometry is invalid.

◆ mbr_contain_cmp()

bool mbr_contain_cmp	(	const dd::Spatial_reference_system *	srs,
		rtr_mbr_t *	a,
		rtr_mbr_t *	b
	)

Checks if one MBR covers another MBR.

Warning: Despite the name, this function computes the covers relation, not contains.

For both MBRs, the coordinates of the MBR's minimum corners must be smaller than or equal to the corresponding coordinates of the maximum corner.

Parameters

[in]	srs	Spatial reference system.
[in]	a	The first MBR.
[in]	b	The second MBR.

Return values

true	MBR a contains MBR b.
false	MBR a doesn't contain MBR b.

◆ mbr_disjoint_cmp()

bool mbr_disjoint_cmp	(	const dd::Spatial_reference_system *	srs,
		rtr_mbr_t *	a,
		rtr_mbr_t *	b
	)

Checks if two MBRs are disjoint.

For both MBRs, the coordinates of the MBR's minimum corners must be smaller than or equal to the corresponding coordinates of the maximum corner.

Return values

true	The MBRs are disjoint.
false	The MBRs intersect each other.

◆ mbr_equal_cmp()

bool mbr_equal_cmp	(	const dd::Spatial_reference_system *	srs,
		rtr_mbr_t *	a,
		rtr_mbr_t *	b
	)

Checks if two MBRs are equal.

For both MBRs, the coordinates of the MBR's minimum corners must be smaller than or equal to the corresponding coordinates of the maximum corner.

Parameters

[in]	srs	Spatial reference system.
[in]	a	The first MBR.
[in]	b	The second MBR.

Return values

true	The two MBRs are equal.
false	The two MBRs aren't equal.

◆ mbr_intersect_cmp()

bool mbr_intersect_cmp	(	const dd::Spatial_reference_system *	srs,
		rtr_mbr_t *	a,
		rtr_mbr_t *	b
	)

Checks if two MBRs intersect each other.

Parameters

[in]	srs	Spatial reference system.
[in]	a	The first MBR.
[in]	b	The second MBR.

For both MBRs, the coordinates of the MBR's minimum corners must be smaller than or equal to the corresponding coordinates of the maximum corner.

Return values

true	The MBRs intersect each other.
false	The MBRs are disjoint.

◆ mbr_join()

void mbr_join	(	const dd::Spatial_reference_system *	srs,
		double *	a,
		const double *	b,
		int	n_dim
	)

Expands an MBR to also cover another MBR.

Note: The function takes a dimension parameter, but currently only supports 2d MBRs.

MBR format: a[0] = xmin, a[1] = xmax, a[2] = ymin, a[3] = ymax. Same for b.

Parameters

[in]	srs	Spatial reference system.
[in,out]	a	The first MBR, where the joined result will be.
[in]	b	The second MBR.
[in]	n_dim	Number of dimensions. Must be 2.

◆ mbr_join_area()

double mbr_join_area	(	const dd::Spatial_reference_system *	srs,
		const double *	a,
		const double *	b,
		int	n_dim
	)

Computes the combined area of two MBRs.

The MBRs may overlap.

Note: The function takes a dimension parameter, but currently only supports 2d MBRs.

Parameters

[in]	srs	Spatial reference system.
[in]	a	The first MBR.
[in]	b	The second MBR.
[in]	n_dim	Number of dimensions. Must be 2.

Returns: The area of MBR a expanded by MBR b.

◆ mbr_within_cmp()

bool mbr_within_cmp	(	const dd::Spatial_reference_system *	srs,
		rtr_mbr_t *	a,
		rtr_mbr_t *	b
	)

Checks if one MBR is covered by another MBR.

Warning: Despite the name, this function computes the covered_by relation, not within.

Note: If the minimum corner coordinates are larger than the corresponding coordinates of the maximum corner, and if not all a and b coordinates are the same, the function returns the inverse result, i.e., return true if a is not covered by b.

Parameters

[in]	srs	Spatial reference system.
[in]	a	The first MBR.
[in]	b	The second MBR.

Return values

true	MBR a is within MBR b.
false	MBR a isn't within MBR b.

◆ rtree_area_increase()

double rtree_area_increase	(	const dd::Spatial_reference_system *	srs,
		const uchar *	mbr_a,
		const uchar *	mbr_b,
		int	mbr_len,
		double *	ab_area
	)

Computes the extra area covered if an MBR is expanded to cover another MBR.

The formula is area(a + b) - area(a). This is generally different from area(b). If MBR b overlaps MBR a, area(a+b) - area(a) < area(b). If they are far apart, area(a+b) - area(a) > area(b).

Note: If MBRs a and b are far apart, the function may return Inf.

Parameters

[in]	srs	Spatial reference system.
[in]	mbr_a	First MBR.
[in]	mbr_b	Second MBR.
[in]	mbr_len	MBR length in bytes. Must be 4 * sizeof(double).
[out]	ab_area	The total area of MBRs a and b combined into one MBR.

Returns: The increase in area when expanding from MBR a to also cover MBR b.

◆ rtree_area_overlapping()

double rtree_area_overlapping	(	const dd::Spatial_reference_system *	srs,
		const uchar *	mbr_a,
		const uchar *	mbr_b,
		int	mbr_len
	)

Calculates the overlapping area between two MBRs.

Parameters

[in]	srs	Spatial reference system.
[in]	mbr_a	First MBR.
[in]	mbr_b	Second MBR.
[in]	mbr_len	MBR length in bytes. Must be 4 * sizeof(double).

Returns: The area of the overlapping region.

Classes

Namespaces

Typedefs

Functions

Detailed Description

Typedef Documentation

◆ rtr_mbr_t

Function Documentation

◆ compute_area()

◆ fetch_srs()

◆ get_mbr_from_store()

◆ mbr_contain_cmp()

◆ mbr_disjoint_cmp()

◆ mbr_equal_cmp()

◆ mbr_intersect_cmp()

◆ mbr_join()

◆ mbr_join_area()

◆ mbr_within_cmp()

◆ rtree_area_increase()

◆ rtree_area_overlapping()