ai.nextbillion.kits.geojson

Class LineString

java.lang.Object

ai.nextbillion.kits.geojson.LineString

All Implemented Interfaces:

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

public final class LineString
extends java.lang.Object
implements CoordinateContainer<java.util.List<Point>>

A linestring represents two or more geographic points that share a relationship 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.

The list of points must be equal to or greater than 2. A LineString has non-zero length and zero area. It may approximate a curve and need not be straight. Unlike a LinearRing, a LineString is not closed.

When representing a LineString that crosses the antimeridian, interoperability is improved by modifying their geometry. Any geometry that crosses the antimeridian SHOULD be represented by cutting it in two such that neither part's representation crosses the antimeridian.

For example, a line extending from 45 degrees N, 170 degrees E across the antimeridian to 45 degrees N, 170 degrees W should be cut in two and represented as a MultiLineString.

A sample GeoJson LineString's provided below (in it's serialized state).

 {
   "TYPE": "LineString",
   "coordinates": [
     [100.0, 0.0],
     [101.0, 1.0]
   ]
 }
 

Look over the Point documentation to get more information about formatting your list of point objects correctly.

See Also:

Serialized Form

Method Summary

Modifier and Type	Method and Description
BoundingBox	bbox() A Feature Collection might have a member named bbox to include information on the coordinate range for it's Features.
java.util.List<Point>	coordinates() Provides the list of Points that make up the LineString geometry.
boolean	equals(java.lang.Object obj)
static LineString	fromJson(java.lang.String json) Create a new instance of this class by passing in a formatted valid JSON String.
static LineString	fromLngLats(java.util.List<Point> points) Create a new instance of this class by defining a list of Points which follow the correct specifications described in the Point documentation.
static LineString	fromLngLats(java.util.List<Point> points, BoundingBox bbox) Create a new instance of this class by defining a list of Points which follow the correct specifications described in the Point documentation.
static LineString	fromLngLats(MultiPoint multiPoint) Create a new instance of this class by defining a MultiPoint object and passing.
static LineString	fromLngLats(MultiPoint multiPoint, BoundingBox bbox) Create a new instance of this class by defining a MultiPoint object and passing.
static LineString	fromPolyline(java.lang.String polyline, int precision) Create a new instance of this class by convert a polyline string into a lineString.
int	hashCode()
java.lang.String	toJson() This takes the currently defined values found inside this instance and converts it to a GeoJson string.
java.lang.String	toPolyline(int precision) Encode this LineString into a Polyline string for easier serializing.
java.lang.String	toString()
java.lang.String	type() This describes the TYPE of GeoJson geometry this object is, thus this will always return LineString.
static com.google.gson.TypeAdapter<LineString>	typeAdapter(com.google.gson.Gson gson) Gson TYPE adapter for parsing Gson to this class.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

fromJson

public static LineString fromJson(java.lang.String json)

Create a new instance of this class by passing in a formatted valid JSON String. If you are creating a LineString object from scratch it is better to use one of the other provided static factory methods such as fromLngLats(List). For a valid lineString to exist, it must have at least 2 coordinate entries. The LineString should also have non-zero distance and zero area.

Parameters:

json - a formatted valid JSON string defining a GeoJson LineString

Returns:

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

fromLngLats

public static LineString fromLngLats(@NonNull
                                     MultiPoint multiPoint)

Create a new instance of this class by defining a MultiPoint object and passing. The multipoint object should comply with the GeoJson specifications described in the documentation.

Parameters:

multiPoint - which will make up the LineString geometry

Returns:

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

fromLngLats

public static LineString fromLngLats(@NonNull
                                     java.util.List<Point> points)

Create a new instance of this class by defining a list of Points which follow the correct specifications described in the Point documentation. Note that there should not be any duplicate points inside the list and the points combined should create a LineString with a distance greater than 0.

Note that if less than 2 points are passed in, a runtime exception will occur.

Parameters:

points - a list of Points which make up the LineString geometry

Returns:

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

fromLngLats

public static LineString fromLngLats(@NonNull
                                     java.util.List<Point> points,
                                     @Nullable
                                     BoundingBox bbox)

Create a new instance of this class by defining a list of Points which follow the correct specifications described in the Point documentation. Note that there should not be any duplicate points inside the list and the points combined should create a LineString with a distance greater than 0.

Note that if less than 2 points are passed in, a runtime exception will occur.

Parameters:

points - a list of Points which make up the LineString geometry

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

fromLngLats

public static LineString fromLngLats(@NonNull
                                     MultiPoint multiPoint,
                                     @Nullable
                                     BoundingBox bbox)

Create a new instance of this class by defining a MultiPoint object and passing. The multipoint object should comply with the GeoJson specifications described in the documentation.

Parameters:

multiPoint - which will make up the LineString geometry

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

fromPolyline

public static LineString fromPolyline(@NonNull
                                      java.lang.String polyline,
                                      int precision)

Create a new instance of this class by convert a polyline string into a lineString. This is handy when an API provides you with an encoded string representing the line geometry and you'd like to convert it to a useful LineString object. Note that the precision that the string geometry was encoded with needs to be known and passed into this method using the precision parameter.

Parameters:

polyline - encoded string geometry to decode into a new LineString instance

precision - The encoded precision which must match the same precision used when the string was first encoded

Returns:

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

type

@NonNull
public java.lang.String type()

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

Specified by:

type in interface GeoJson

Returns:

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

bbox

@Nullable
public 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

coordinates

@NonNull
public java.util.List<Point> coordinates()

Provides the list of Points that make up the LineString geometry.

Specified by:

coordinates in interface CoordinateContainer<java.util.List<Point>>

Returns:

a list of points

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 LineString geometry

toPolyline

public java.lang.String toPolyline(int precision)

Encode this LineString into a Polyline string for easier serializing. When passing geometry information over a mobile network connection, encoding the geometry first will generally result in less bandwidth usage.

Parameters:

precision - the encoded precision which fits your best use-case

Returns:

a string describing the geometry of this LineString

typeAdapter

public static com.google.gson.TypeAdapter<LineString> 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

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object