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GMSGeometryUtils

GMSGeometryUtils

Classes

struct  GMSMapPoint
 A point on the map. More...

Typedefs

typedef struct GMSMapPoint GMSMapPoint
 A point on the map.

Functions

GMSMapPoint GMSProject (CLLocationCoordinate2D coordinate)
 Projects coordinate to the map.
CLLocationCoordinate2D GMSUnproject (GMSMapPoint point)
 Unprojects point from the map.
GMSMapPoint GMSMapPointInterpolate (GMSMapPoint a, GMSMapPoint b, double t)
 Returns a linearly interpolated point on the segment [a, b], at the fraction t from a.
double GMSMapPointDistance (GMSMapPoint a, GMSMapPoint b)
 Returns the length of the segment [a, b] in projected space.
BOOL GMSGeometryContainsLocation (CLLocationCoordinate2D point, GMSPath *path, BOOL geodesic)
 Returns whether point lies inside of path.
BOOL GMSGeometryIsLocationOnPathTolerance (CLLocationCoordinate2D point, GMSPath *path, BOOL geodesic, CLLocationDistance tolerance)
 Returns whether point lies on or near path, within the specified tolerance in meters.
BOOL GMSGeometryIsLocationOnPath (CLLocationCoordinate2D point, GMSPath *path, BOOL geodesic)
 Same as GMSGeometryIsLocationOnPath(point, path, geodesic, tolerance), with a default tolerance of 0.1 meters.
CLLocationDistance GMSGeometryDistance (CLLocationCoordinate2D from, CLLocationCoordinate2D to)
 Returns the great circle distance between two coordinates, in meters, on Earth.
CLLocationDistance GMSGeometryLength (GMSPath *path)
 Returns the great circle length of path, in meters, on Earth.
double GMSGeometryArea (GMSPath *path)
 Returns the area of a geodesic polygon defined by path on Earth.
double GMSGeometrySignedArea (GMSPath *path)
 Returns the signed area of a geodesic polygon defined by path on Earth.
CLLocationDirection GMSGeometryHeading (CLLocationCoordinate2D from, CLLocationCoordinate2D to)
 Returns the initial heading (degrees clockwise of North) at from of the shortest path to to.
CLLocationCoordinate2D GMSGeometryOffset (CLLocationCoordinate2D from, CLLocationDistance distance, CLLocationDirection heading)
 Returns the destination coordinate, when starting at from with initial heading, travelling distance meters along a great circle arc, on Earth.
CLLocationCoordinate2D GMSGeometryInterpolate (CLLocationCoordinate2D from, CLLocationCoordinate2D to, double fraction)
 Returns the coordinate that lies the given fraction of the way between the from and to coordinates on the shortest path between the two.
NSArray< GMSStyleSpan * > * GMSStyleSpans (GMSPath *path, NSArray< GMSStrokeStyle * > *styles, NSArray< NSNumber * > *lengths, GMSLengthKind lengthKind)
 Returns an NSArray of GMSStyleSpan constructed by repeated application of style and length information from styles and lengths along path.
NSArray< GMSStyleSpan * > * GMSStyleSpansOffset (GMSPath *path, NSArray< GMSStrokeStyle * > *styles, NSArray< NSNumber * > *lengths, GMSLengthKind lengthKind, double lengthOffset)
 Similar to GMSStyleSpans(path, styles, lengths, lengthKind) but additionally takes an initial length offset that will be skipped over relative to the lengths array.

Typedef Documentation

typedef struct GMSMapPoint GMSMapPoint

A point on the map.

May represent a projected coordinate.

x is in [-1, 1]. The axis direction is normal: y grows towards North, x grows towards East. (0, 0) is the center of the map.

See GMSProject() and GMSUnproject().


Function Documentation

GMSMapPoint GMSProject ( CLLocationCoordinate2D  coordinate)

Projects coordinate to the map.

coordinate must be valid.

CLLocationCoordinate2D GMSUnproject ( GMSMapPoint  point)

Unprojects point from the map.

point.x must be in [-1, 1].

Returns a linearly interpolated point on the segment [a, b], at the fraction t from a.

t==0 corresponds to a, t==1 corresponds to b.

The interpolation takes place along the short path between the points potentially crossing the date line. E.g. interpolating from San Francisco to Tokyo will pass north of Hawaii and cross the date line.

Returns the length of the segment [a, b] in projected space.

The length is computed along the short path between the points potentially crossing the date line. E.g. the distance between the points corresponding to San Francisco and Tokyo measures the segment that passes north of Hawaii crossing the date line.

BOOL GMSGeometryContainsLocation ( CLLocationCoordinate2D  point,
GMSPath path,
BOOL  geodesic 
)

Returns whether point lies inside of path.

The path is always considered closed, regardless of whether the last point equals the first or not.

Inside is defined as not containing the South Pole -- the South Pole is always outside.

path describes great circle segments if geodesic is YES, and rhumb (loxodromic) segments otherwise.

If point is exactly equal to one of the vertices, the result is YES. A point that is not equal to a vertex is on one side or the other of any path segment -- it can never be "exactly on the border".

See GMSGeometryIsLocationOnPath() for a border test with tolerance.

BOOL GMSGeometryIsLocationOnPathTolerance ( CLLocationCoordinate2D  point,
GMSPath path,
BOOL  geodesic,
CLLocationDistance  tolerance 
)

Returns whether point lies on or near path, within the specified tolerance in meters.

path is composed of great circle segments if geodesic is YES, and of rhumb (loxodromic) segments if geodesic is NO.

See also GMSGeometryIsLocationOnPath(point, path, geodesic).

The tolerance, in meters, is relative to the spherical radius of the Earth. If you need to work on a sphere of different radius, you may compute the equivalent tolerance from the desired tolerance on the sphere of radius R: tolerance = toleranceR * (RadiusEarth / R), with RadiusEarth==6371009.

BOOL GMSGeometryIsLocationOnPath ( CLLocationCoordinate2D  point,
GMSPath path,
BOOL  geodesic 
)

Same as GMSGeometryIsLocationOnPath(point, path, geodesic, tolerance), with a default tolerance of 0.1 meters.

CLLocationDistance GMSGeometryDistance ( CLLocationCoordinate2D  from,
CLLocationCoordinate2D  to 
)

Returns the great circle distance between two coordinates, in meters, on Earth.

This is the shortest distance between the two coordinates on the sphere.

Both coordinates must be valid.

CLLocationDistance GMSGeometryLength ( GMSPath path)

Returns the great circle length of path, in meters, on Earth.

This is the sum of GMSGeometryDistance() over the path segments.

All the coordinates of the path must be valid.

double GMSGeometryArea ( GMSPath path)

Returns the area of a geodesic polygon defined by path on Earth.

The "inside" of the polygon is defined as not containing the South pole.

If path is not closed, it is implicitly treated as a closed path nevertheless and the result is the same.

All coordinates of the path must be valid.

The polygon must be simple (not self-overlapping) and may be concave.

If any segment of the path is a pair of antipodal points, the result is undefined -- because two antipodal points do not form a unique great circle segment on the sphere.

double GMSGeometrySignedArea ( GMSPath path)

Returns the signed area of a geodesic polygon defined by path on Earth.

The result has the same absolute value as GMSGeometryArea(); it is positive if the points of path are in counter-clockwise order, and negative otherwise.

The same restrictions as on GMSGeometryArea() apply.

CLLocationDirection GMSGeometryHeading ( CLLocationCoordinate2D  from,
CLLocationCoordinate2D  to 
)

Returns the initial heading (degrees clockwise of North) at from of the shortest path to to.

The returned value is in the range [0, 360).

Returns 0 if the two coordinates are the same.

Both coordinates must be valid.

To get the final heading at to one may use (GMSGeometryHeading(to, from) + 180) modulo 360.

CLLocationCoordinate2D GMSGeometryOffset ( CLLocationCoordinate2D  from,
CLLocationDistance  distance,
CLLocationDirection  heading 
)

Returns the destination coordinate, when starting at from with initial heading, travelling distance meters along a great circle arc, on Earth.

The resulting longitude is in the range [-180, 180).

Both coordinates must be valid.

CLLocationCoordinate2D GMSGeometryInterpolate ( CLLocationCoordinate2D  from,
CLLocationCoordinate2D  to,
double  fraction 
)

Returns the coordinate that lies the given fraction of the way between the from and to coordinates on the shortest path between the two.

The resulting longitude is in the range [-180, 180).

NSArray<GMSStyleSpan *>* GMSStyleSpans ( GMSPath path,
NSArray< GMSStrokeStyle * > *  styles,
NSArray< NSNumber * > *  lengths,
GMSLengthKind  lengthKind 
)

Returns an NSArray of GMSStyleSpan constructed by repeated application of style and length information from styles and lengths along path.

path the path along which the output spans are computed. styles an NSArray of GMSStrokeStyle. Wraps if consumed. Can't be empty. lengths an NSArray of NSNumber; each entry gives the length of the corresponding style from styles. Wraps if consumed. Can't be empty. lengthKind the interpretation of values from lengths (geodesic, rhumb or projected).

Example: a polyline with alternating black and white spans:

 GMSMutablePath *path;
 NSArray *styles = @[[GMSStrokeStyle solidColor:[UIColor whiteColor]],
                     [GMSStrokeStyle solidColor:[UIColor blackColor]]];
 NSArray *lengths = @[@100000, @50000];
 polyline.path = path;
 polyline.spans = GMSStyleSpans(path, styles, lengths, kGMSLengthRhumb);
 
NSArray<GMSStyleSpan *>* GMSStyleSpansOffset ( GMSPath path,
NSArray< GMSStrokeStyle * > *  styles,
NSArray< NSNumber * > *  lengths,
GMSLengthKind  lengthKind,
double  lengthOffset 
)

Similar to GMSStyleSpans(path, styles, lengths, lengthKind) but additionally takes an initial length offset that will be skipped over relative to the lengths array.

lengthOffset the length (e.g. in meters) that should be skipped initially from lengths.

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