A Feature that represents a grouping of related features or a complex polygon. More...

#include <Relation.h>

Inheritance diagram for geodesk::Relation:

Public Member Functions
Type & Identity
FeatureType	type () const noexcept
	`FeatureType::RELATION`

int64_t	id () const noexcept
	The ID of this Relation.

bool	isNode () const noexcept
	Always `false`

bool	isAnonymousNode () const noexcept
	Always `false`

bool	isWay () const noexcept
	Always `false`

bool	isRelation () const noexcept
	Always `true`

bool	isArea () const noexcept
	`true` if this Relation represents an area.

bool	belongsToRelation () const noexcept
	`true` if this Relation itself belongs to at least one Relation.

StringValue	role () const noexcept
	The Relation's role in its parent Relation, if it was returned via members() or Features::membersOf(), otherwise an empty string.

Display
const char *	typeName () const noexcept
	`"node"`, `"way"` or `"relation"`

char *	format (char *buf) const noexcept
	Formats the string representation (e.g. `"node/123456"`) of this Feature into the provided buffer.

std::string	toString () const
	Creates a `std::string` with the Feature's type and ID.

std::string	label () const
	Creates a short descriptive label.

Tags
TagValue	operator[] (std::string_view key) const noexcept
	Obtains the tag value for the given key.

Tags	tags () const noexcept
	A collection of the Feature's tags.

bool	hasTag (std::string_view k) const noexcept
	Checks if this Feature has a tag with the given key.

bool	hasTag (std::string_view k, std::string_view v) const noexcept
	Checks if this Feature has a tag with the given key and value.

Geometry
Box	bounds () const noexcept
	The bounding box of this Feature.

Coordinate	xy () const noexcept
	The Mercator-projected x/y coordinate of a Node, or the center point of the bounding box for a Way or Relation.

int32_t	x () const noexcept
	The Mercator-projected x-coordinate of a Node, or the horizontal midpoint of the bounding box for a Way or Relation.

int32_t	y () const noexcept
	The Mercator-projected y-coordinate of a Node, or the vertical midpoint of the bounding box for a Way or Relation.

double	lon () const noexcept
	The longitude of this feature (in WGS-84 degrees).

double	lat () const noexcept
	The latitude of this feature (in WGS-84 degrees).

Coordinate	centroid () const
	Computes the centroid of this Feature.

double	area () const
	Measures the area of this Feature.

double	length () const
	Measures the length of this Feature.

GEOSGeometry *	toGeometry (GEOSContextHandle_t geosContext) const
	Creates a `GEOSGeometry` based on this Feature's geometry.

Related Features
Nodes	nodes () const
	The nodes of this Way.

Nodes	nodes (const char *query) const
	The nodes of this Way that match the given query.

Features	members () const
	The members of this Relation.

Features	members (const char *query) const
	The members of this Relation that match the given query.

Features	parents () const
	The parent relations of this Feature (and the parent ways for a Node).

Features	parents (const char *query) const
	The parent relations of this Feature (and the parent ways for a Node) that match the given query.

Access to the Low-Level API
FeaturePtr	ptr () const noexcept
	Pointer to the stored data of this Feature.

FeatureStore *	store () const noexcept
	Pointer to the FeatureStore which contains this Feature.

Detailed Description

A Feature that represents a grouping of related features or a complex polygon.

Each Relation has one or more member features, which can be retrieved via members(). Each Feature object returned by members() has its role set to a non-empty string, if it has an explicit role in this Relation (e.g. "stop" for a Node in a route relation that represents a bus stop).

Note: Functions that require the complete geometry of a Relation (such as area() or centroid()) may fail with a QueryException if one or more tiles that contain members of the Relation are missing.

Member Function Documentation

◆ area()

double geodesk::Feature::area ( ) const

inherited

Measures the area of this Feature.

Returns: area (in square meters), or 0 if the feature is not polygonal

Exceptions

QueryException if one or more tiles that contain the geometry of a Relation are missing

◆ belongsToRelation()

bool geodesk::Relation::belongsToRelation ( ) const

noexcept

true if this Relation itself belongs to at least one Relation.

◆ bounds()

Box geodesk::Feature::bounds ( ) const

noexceptinherited

The bounding box of this Feature.

Returns: The Feature's bounding box (in Mercator projection)

◆ centroid()

Coordinate geodesk::Feature::centroid ( ) const

inherited

Computes the centroid of this Feature.

Returns: the Feature's centroid (in Mercator projection)

Exceptions

QueryException if one or more tiles that contain the geometry of a Relation are missing

◆ format()

char * geodesk::Feature::format ( char * buf ) const

noexceptinherited

Formats the string representation (e.g. "node/123456") of this Feature into the provided buffer.

Appends a null-terminator at the end of the output, and returns a pointer to the null-terminator, allowing easy concatenation.

Parameters

buf	pointer to a `char` array of sufficient size

Returns: a pointer to the null-terminator of the string in buf

◆ hasTag() [1/2]

bool geodesk::Feature::hasTag ( std::string_view k ) const

noexceptinherited

Checks if this Feature has a tag with the given key.

◆ hasTag() [2/2]

bool geodesk::Feature::hasTag	(	std::string_view	k,
		std::string_view	v ) const

noexceptinherited

Checks if this Feature has a tag with the given key and value.

◆ id()

int64_t geodesk::Relation::id ( ) const

noexcept

The ID of this Relation.

◆ isAnonymousNode()

bool geodesk::Relation::isAnonymousNode ( ) const

noexcept

Always false

◆ isArea()

bool geodesk::Relation::isArea ( ) const

noexcept

true if this Relation represents an area.

◆ isNode()

bool geodesk::Relation::isNode ( ) const

noexcept

Always false

◆ isRelation()

bool geodesk::Relation::isRelation ( ) const

noexcept

Always true

◆ isWay()

bool geodesk::Relation::isWay ( ) const

noexcept

Always false

◆ label()

std::string geodesk::Feature::label ( ) const

inherited

Creates a short descriptive label.

This is usually a combination of the type and name, such as hotel "Four Seasons".

◆ lat()

double geodesk::Feature::lat ( ) const

noexceptinherited

The latitude of this feature (in WGS-84 degrees).

For a Way or Relation, this is the vertical midpoint of its bounding box.

◆ length()

double geodesk::Feature::length ( ) const

inherited

Measures the length of this Feature.

Returns: length (in meters), or 0 if the feature is not lineal

Exceptions

QueryException if one or more tiles that contain the geometry of a Relation are missing

◆ lon()

double geodesk::Feature::lon ( ) const

noexceptinherited

The longitude of this feature (in WGS-84 degrees).

For a Way or Relation, this is the horizontal midpoint of its bounding box.

◆ members() [1/2]

Features geodesk::Feature::members ( ) const

inherited

The members of this Relation.

Returns: an ordered collection of Feature objects

◆ members() [2/2]

Features geodesk::Feature::members ( const char * query ) const

inherited

The members of this Relation that match the given query.

Parameters

query a query in GOQL format

Returns: an ordered collection of Feature objects

Exceptions

QueryException if the query is malformed.

◆ nodes() [1/2]

Nodes geodesk::Feature::nodes ( ) const

inherited

The nodes of this Way.

Returns: an ordered collection of Node objects

◆ nodes() [2/2]

Nodes geodesk::Feature::nodes ( const char * query ) const

inherited

The nodes of this Way that match the given query.

Parameters

query a query in GOQL format

Returns: an ordered collection of Node objects

Exceptions

QueryException if the query is malformed.

◆ operator[]()

TagValue geodesk::Feature::operator[] ( std::string_view key ) const

noexceptinherited

Obtains the tag value for the given key.

Returns: the tag's value (or an empty string if the feature doesn't have a tag with this key)

◆ parents() [1/2]

Features geodesk::Feature::parents ( ) const

inherited

The parent relations of this Feature (and the parent ways for a Node).

Returns: a collection of Relation objects (Way and Relation for Node)

◆ parents() [2/2]

Features geodesk::Feature::parents ( const char * query ) const

inherited

The parent relations of this Feature (and the parent ways for a Node) that match the given query.

Parameters

query a query in GOQL format

Returns: a collection of Relation objects (Way and Relation for Node)

Exceptions

QueryException if the query is malformed.

◆ ptr()

FeaturePtr geodesk::Feature::ptr ( ) const

noexceptinherited

Pointer to the stored data of this Feature.

If this Feature is an anonymous node, the FeaturePtr will be a nullptr

◆ role()

StringValue geodesk::Relation::role ( ) const

noexcept

The Relation's role in its parent Relation, if it was returned via members() or Features::membersOf(), otherwise an empty string.

Returns: the Relation's role (or an empty string)

◆ store()

FeatureStore * geodesk::Feature::store ( ) const

noexceptinherited

Pointer to the FeatureStore which contains this Feature.

◆ tags()

Tags geodesk::Feature::tags ( ) const

noexceptinherited

A collection of the Feature's tags.

◆ toGeometry()

GEOSGeometry * geodesk::Feature::toGeometry ( GEOSContextHandle_t geosContext ) const

inherited

Creates a GEOSGeometry based on this Feature's geometry.

Coordinates will be in Mercator projection. The caller assumes ownership of the newly created GEOSGeometry and is responsible for its cleanup.

This method is only available if build option GEODESK_WITH_GEOS is enabled (off by default).

Parameters

geosContext The GEOS context o use

Returns: the pointer to the newly-created GEOSGeometry

◆ toString()

std::string geodesk::Feature::toString ( ) const

inherited

Creates a std::string with the Feature's type and ID.

Returns: a std::string (e.g. "node/123456")

◆ type()

FeatureType geodesk::Relation::type ( ) const

noexcept

FeatureType::RELATION

◆ typeName()

const char * geodesk::Feature::typeName ( ) const

noexceptinherited

"node", "way" or "relation"

Returns: pointer null-terminated constant string

◆ x()

int32_t geodesk::Feature::x ( ) const

noexceptinherited

The Mercator-projected x-coordinate of a Node, or the horizontal midpoint of the bounding box for a Way or Relation.

◆ xy()

Coordinate geodesk::Feature::xy ( ) const

noexceptinherited

The Mercator-projected x/y coordinate of a Node, or the center point of the bounding box for a Way or Relation.

◆ y()

int32_t geodesk::Feature::y ( ) const

noexceptinherited

The Mercator-projected y-coordinate of a Node, or the vertical midpoint of the bounding box for a Way or Relation.

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

C:/dev/libgeodesk/include/geodesk/api/Relation.h

Public Member Functions

Detailed Description

Member Function Documentation

◆ area()

◆ belongsToRelation()

◆ bounds()

◆ centroid()

◆ format()

◆ hasTag() [1/2]

◆ hasTag() [2/2]

◆ id()

◆ isAnonymousNode()

◆ isArea()

◆ isNode()

◆ isRelation()

◆ isWay()

◆ label()

◆ lat()

◆ length()

◆ lon()

◆ members() [1/2]

◆ members() [2/2]

◆ nodes() [1/2]

◆ nodes() [2/2]

◆ operator[]()

◆ parents() [1/2]

◆ parents() [2/2]

◆ ptr()

◆ role()

◆ store()

◆ tags()

◆ toGeometry()

◆ toString()

◆ type()

◆ typeName()

◆ x()

◆ xy()

◆ y()