com.mapbox.geojson

Class Point

java.lang.Object

com.mapbox.geojson.Point

All Implemented Interfaces:

CoordinateContainer<java.util.List<java.lang.Double>>, GeoJson, Geometry, java.io.Serializable

public abstract class Point
extends java.lang.Object
implements CoordinateContainer<java.util.List<java.lang.Double>>, java.io.Serializable

A point represents a single geographic position and is one of the seven Geometries found in the GeoJson spec.

This adheres to the RFC 7946 internet standard when serialized into JSON. When deserialized, this class becomes an immutable object which should be initiated using its static factory methods.

Coordinates are in x, y order (easting, northing for projected coordinates), longitude, and latitude for geographic coordinates), precisely in that order and using double values. Altitude or elevation MAY be included as an optional third parameter while creating this object.

The size of a GeoJson text in bytes is a major interoperability consideration, and precision of coordinate values has a large impact on the size of texts when serialized. For geographic coordinates with units of degrees, 6 decimal places (a default common in, e.g., sprintf) amounts to about 10 centimeters, a precision well within that of current GPS systems. Implementations should consider the cost of using a greater precision than necessary.

Furthermore, pertaining to altitude, the WGS 84 datum is a relatively coarse approximation of the geoid, with the height varying by up to 5 m (but generally between 2 and 3 meters) higher or lower relative to a surface parallel to Earth's mean sea level.

A sample GeoJson Point's provided below (in its serialized state).

 {
   "type": "Point",
   "coordinates": [100.0, 0.0]
 }
 

Since:

1.0.0

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
Point()

Method Summary

Modifier and Type	Method and Description
double	altitude() Optionally, the coordinate spec in GeoJson allows for altitude values to be placed inside the coordinate array.
abstract BoundingBox	bbox() A Feature Collection might have a member named bbox to include information on the coordinate range for it's Features.
abstract java.util.List<java.lang.Double>	coordinates() Provide a single double array containing the longitude, latitude, and optionally an altitude/elevation.
static Point	fromJson(java.lang.String json) Create a new instance of this class by passing in a formatted valid JSON String.
static Point	fromLngLat(double longitude, double latitude) Create a new instance of this class defining a longitude and latitude value in that respective order.
static Point	fromLngLat(double longitude, double latitude, BoundingBox bbox) Create a new instance of this class defining a longitude and latitude value in that respective order.
static Point	fromLngLat(double longitude, double latitude, double altitude) Create a new instance of this class defining a longitude and latitude value in that respective order.
static Point	fromLngLat(double longitude, double latitude, double altitude, BoundingBox bbox) Create a new instance of this class defining a longitude and latitude value in that respective order.
boolean	hasAltitude() Optionally, the coordinate spec in GeoJson allows for altitude values to be placed inside the coordinate array.
double	latitude() This returns a double value ranging from -90 to 90 representing the y or northing position of this point.
double	longitude() This returns a double value ranging from -180 to 180 representing the x or easting position of this point.
java.lang.String	toJson() This takes the currently defined values found inside this instance and converts it to a GeoJson string.
abstract java.lang.String	type() This describes the TYPE of GeoJson geometry this object is, thus this will always return Point.
static com.google.gson.TypeAdapter<Point>	typeAdapter(com.google.gson.Gson gson) Gson TYPE adapter for parsing Gson to this class.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Point

public Point()

Method Detail

fromJson

public static Point fromJson(@NonNull
                             java.lang.String json)

Create a new instance of this class by passing in a formatted valid JSON String. If you are creating a Point object from scratch it is better to use one of the other provided static factory methods such as fromLngLat(double, double). Longitude values should not exceed the spec defined -180 to 180 range and latitude's limit of -90 to 90. While no limit is placed on decimal precision, for performance reasons when serializing and deserializing it is suggested to limit decimal precision to within 6 decimal places.

Parameters:

json - a formatted valid JSON string defining a GeoJson Point

Returns:

a new instance of this class defined by the values passed inside this static factory method

Since:

1.0.0

fromLngLat

public static Point fromLngLat(double longitude,
                               double latitude)

Create a new instance of this class defining a longitude and latitude value in that respective order. Longitude values are limited to a -180 to 180 range and latitude's limited to -90 to 90 as the spec defines. While no limit is placed on decimal precision, for performance reasons when serializing and deserializing it is suggested to limit decimal precision to within 6 decimal places.

Parameters:

longitude - a double value between -180 to 180 representing the x position of this point

latitude - a double value between -90 to 90 representing the y position of this point

Returns:

a new instance of this class defined by the values passed inside this static factory method

Since:

3.0.0

fromLngLat

public static Point fromLngLat(double longitude,
                               double latitude,
                               @Nullable
                               BoundingBox bbox)

Create a new instance of this class defining a longitude and latitude value in that respective order. Longitude values are limited to a -180 to 180 range and latitude's limited to -90 to 90 as the spec defines. While no limit is placed on decimal precision, for performance reasons when serializing and deserializing it is suggested to limit decimal precision to within 6 decimal places. An optional altitude value can be passed in and can vary between negative infinity and positive infinity.

Parameters:

longitude - a double value between -180 to 180 representing the x position of this point

latitude - a double value between -90 to 90 representing the y position of this point

bbox - optionally include a bbox definition as a double array

Returns:

a new instance of this class defined by the values passed inside this static factory method

Since:

3.0.0

fromLngLat

public static Point fromLngLat(double longitude,
                               double latitude,
                               double altitude)

Create a new instance of this class defining a longitude and latitude value in that respective order. Longitude values are limited to a -180 to 180 range and latitude's limited to -90 to 90 as the spec defines. While no limit is placed on decimal precision, for performance reasons when serializing and deserializing it is suggested to limit decimal precision to within 6 decimal places. An optional altitude value can be passed in and can vary between negative infinity and positive infinity.

Parameters:

longitude - a double value between -180 to 180 representing the x position of this point

latitude - a double value between -90 to 90 representing the y position of this point

altitude - a double value which can be negative or positive infinity representing either elevation or altitude

Returns:

a new instance of this class defined by the values passed inside this static factory method

Since:

3.0.0

fromLngLat

public static Point fromLngLat(double longitude,
                               double latitude,
                               double altitude,
                               @Nullable
                               BoundingBox bbox)

Create a new instance of this class defining a longitude and latitude value in that respective order. Longitude values are limited to a -180 to 180 range and latitude's limited to -90 to 90 as the spec defines. While no limit is placed on decimal precision, for performance reasons when serializing and deserializing it is suggested to limit decimal precision to within 6 decimal places. An optional altitude value can be passed in and can vary between negative infinity and positive infinity.

Parameters:

longitude - a double value between -180 to 180 representing the x position of this point

latitude - a double value between -90 to 90 representing the y position of this point

altitude - a double value which can be negative or positive infinity representing either elevation or altitude

bbox - optionally include a bbox definition as a double array

Returns:

a new instance of this class defined by the values passed inside this static factory method

Since:

3.0.0

longitude

public double longitude()

This returns a double value ranging from -180 to 180 representing the x or easting position of this point. ideally, this value would be restricted to 6 decimal places to correctly follow the GeoJson spec.

Returns:

a double value ranging from -180 to 180 representing the x or easting position of this point

Since:

3.0.0

latitude

public double latitude()

This returns a double value ranging from -90 to 90 representing the y or northing position of this point. ideally, this value would be restricted to 6 decimal places to correctly follow the GeoJson spec.

Returns:

a double value ranging from -90 to 90 representing the y or northing position of this point

Since:

3.0.0

altitude

public double altitude()

Optionally, the coordinate spec in GeoJson allows for altitude values to be placed inside the coordinate array. hasAltitude() can be used to determine if this value was set during initialization of this Point instance. This double value should only be used to represent either the elevation or altitude value at this particular point.

Returns:

a double value ranging from negative to positive infinity

Since:

3.0.0

hasAltitude

public boolean hasAltitude()

Optionally, the coordinate spec in GeoJson allows for altitude values to be placed inside the coordinate array. If an altitude value was provided while initializing this instance, this will return true.

Returns:

true if this instance of point contains an altitude value

Since:

3.0.0

type

@NonNull
public abstract java.lang.String type()

This describes the TYPE of GeoJson geometry this object is, thus this will always return Point.

Specified by:

type in interface GeoJson

Returns:

a String which describes the TYPE of geometry, for this object it will always return Point

Since:

1.0.0

bbox

@Nullable
public abstract BoundingBox bbox()

A Feature Collection might have a member named bbox to include information on the coordinate range for it's Features. The value of the bbox member MUST be a list of size 2*n where n is the number of dimensions represented in the contained feature geometries, with all axes of the most southwesterly point followed by all axes of the more northeasterly point. The axes order of a bbox follows the axes order of geometries.

Specified by:

bbox in interface GeoJson

Returns:

a list of double coordinate values describing a bounding box

Since:

3.0.0

coordinates

@NonNull
public abstract java.util.List<java.lang.Double> coordinates()

Provide a single double array containing the longitude, latitude, and optionally an altitude/elevation. longitude(), latitude(), and altitude() are all avaliable which make getting specific coordinates more direct.

Specified by:

coordinates in interface CoordinateContainer<java.util.List<java.lang.Double>>

Returns:

a double array which holds this points coordinates

Since:

3.0.0

toJson

public java.lang.String toJson()

This takes the currently defined values found inside this instance and converts it to a GeoJson string.

Specified by:

toJson in interface GeoJson

Returns:

a JSON string which represents this Point geometry

Since:

1.0.0

typeAdapter

public static com.google.gson.TypeAdapter<Point> typeAdapter(com.google.gson.Gson gson)

Gson TYPE adapter for parsing Gson to this class.

Parameters:

gson - the built Gson object

Returns:

the TYPE adapter for this class

Since:

3.0.0