com.allanbank.mongodb.builder

Class GeoJson

java.lang.Object

com.allanbank.mongodb.builder.GeoJson

public final class GeoJson
extends Object

GeoJson provides static methods to help create GeoJSON BSON Documents.

This class uses the Point and Point2D classes to represent GeoJSON positions. To assist in converting raw (x, y) coordinates the p(double, double) and p(int, int) methods are provides to quickly construct the Point instances.

As an example of using this class consider the following Polygon with a hole from the GeoJSON specification:

 
 { "type": "Polygon",
   "coordinates": [
     [ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ],
     [ [100.2, 0.2], [100.8, 0.2], [100.8, 0.8], [100.2, 0.8], [100.2, 0.2] ]
     ]
  }
 
 

The equivalent BSON document can be constructed via:

 
 import static com.allanbank.mongodb.builder.GeoJson.polygon;
 import static com.allanbank.mongodb.builder.GeoJson.p;
 
 Document geoJsonPolygon = polygon(
      Arrays.asList( p(100.0, 0.0), p(101.0, 0.0), p(101.0, 1.0), p(100.0, 1.0), p(100.0, 0.0) ),
      Arrays.asList( p(100.2, 0.2), p(100.8, 0.2), p(100.8, 0.8), p(100.2, 0.8), p(100.2, 0.2) ) );
 
 

See Also:

The GeoJSON Format Specification

Copyright ©:

2013, Allanbank Consulting, Inc., All Rights Reserved

Method Summary

Methods

Modifier and Type	Method and Description
protected static void	add(ArrayBuilder coordinates, List<? extends Point2D> positions) Adds a positions to the coordinates array.
protected static void	add(ArrayBuilder coordinates, Point2D position) Adds a position to the coordinates array.
protected static void	addRaw(ArrayBuilder arrayBuilder, Point2D position) Adds the (x,y) coordinates from the point directly to the array provided.
protected static void	lineRing(ArrayBuilder positionArray, List<? extends Point2D> positions) Fills in the LineRing coordinates.
static Document	lineString(List<? extends Point2D> points) Constructs a GeoJSON 'LineString' document from the coordinates provided.
static Document	lineString(Point2D p1, Point2D p2, Point2D... remaining) Constructs a GeoJSON 'LineString' document from the coordinates provided.
static Document	multiLineString(List<? extends Point2D> firstLineString, List<? extends Point2D>... additionalLineStrings) Constructs a GeoJSON 'MultiLineString' document from the coordinates provided.
static Document	multiPoint(List<? extends Point2D> positions) Constructs a GeoJSON 'MultiPoint' document from the positions provided.
static Document	multiPoint(Point2D firstPosition, Point2D... additionalPositions) Constructs a GeoJSON 'MultiPoint' document from the positions provided.
static Point2D	p(double x, double y) Helper method to construct a Point2D from the (x, y) coordinates.
static Point	p(int x, int y) Helper method to construct a Point from the (x, y) coordinates.
static Document	point(Point2D position) Constructs a GeoJSON 'Point' document from the coordinates provided.
static Document	polygon(List<? extends Point2D> boundary) Constructs a GeoJSON 'Polygon' document from the coordinates provided.
static Document	polygon(List<? extends Point2D> boundary, List<? extends Point2D>... holes) Constructs a GeoJSON 'Polygon' document from the coordinates provided.

Methods inherited from class java.lang.Object

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

Method Detail

lineString

public static Document lineString(List<? extends Point2D> points)
                           throws IllegalArgumentException

Constructs a GeoJSON 'LineString' document from the coordinates provided.

Parameters:

points - The positions in the line string. There should be at least 2 positions for the document to be a valid LineString.

Returns:

A GeoJSON LineString document from the coordinates provided.

Throws:

IllegalArgumentException - If the list does not contain at least 2 points.

See Also:

GeoJSON LineString

lineString

public static Document lineString(Point2D p1,
                  Point2D p2,
                  Point2D... remaining)

Constructs a GeoJSON 'LineString' document from the coordinates provided.

Parameters:

p1 - The first position in the line string.

p2 - The second position in the line string.

remaining - The remaining positions in the line string.

Returns:

A GeoJSON LineString document from the coordinates provided.

See Also:

GeoJSON LineString

multiLineString

public static Document multiLineString(List<? extends Point2D> firstLineString,
                       List<? extends Point2D>... additionalLineStrings)

Constructs a GeoJSON 'MultiLineString' document from the coordinates provided.

Note: You will need to add a @SuppressWarnings("unchecked") to uses of this method as Java does not like mixing generics and varargs. The @SafeVarargs annotation is not available in Java 1.6, the minimum version for the driver.

Parameters:

firstLineString - The first line string.

additionalLineStrings - The remaining line strings.

Returns:

A GeoJSON MultiLineString document from the coordinates provided.

See Also:

GeoJSON Polygon

multiPoint

public static Document multiPoint(List<? extends Point2D> positions)

Constructs a GeoJSON 'MultiPoint' document from the positions provided.

Parameters:

positions - The positions

Returns:

A GeoJSON MultiPoint document from the coordinates provided.

See Also:

GeoJSON Point

multiPoint

public static Document multiPoint(Point2D firstPosition,
                  Point2D... additionalPositions)

Constructs a GeoJSON 'MultiPoint' document from the positions provided.

Parameters:

firstPosition - The first position

additionalPositions - The other positions

Returns:

A GeoJSON MultiPoint document from the coordinates provided.

See Also:

GeoJSON Point

p

public static Point2D p(double x,
        double y)

Helper method to construct a Point2D from the (x, y) coordinates.

Parameters:

x - The point's x position

y - The point's y position

Returns:

A Point for the coordinates provided.

p

public static Point p(int x,
      int y)

Helper method to construct a Point from the (x, y) coordinates.

Parameters:

x - The point's x position

y - The point's y position

Returns:

A Point for the coordinates provided.

point

public static Document point(Point2D position)

Constructs a GeoJSON 'Point' document from the coordinates provided.

Parameters:

position - The point's position

Returns:

A GeoJSON Point document from the coordinates provided.

See Also:

GeoJSON Point

polygon

public static Document polygon(List<? extends Point2D> boundary)
                        throws IllegalArgumentException

Constructs a GeoJSON 'Polygon' document from the coordinates provided.

Parameters:

boundary - The boundary positions for the polygon.

Returns:

A GeoJSON Polygon document from the coordinates provided.

Throws:

IllegalArgumentException - If the line ring does not have at least 4 positions or the first and last positions are not equivalent.

See Also:

GeoJSON Polygon

polygon

public static Document polygon(List<? extends Point2D> boundary,
               List<? extends Point2D>... holes)
                        throws IllegalArgumentException

Constructs a GeoJSON 'Polygon' document from the coordinates provided.

Note: You will need to add a @SuppressWarnings("unchecked") to uses of this method as Java does not like mixing generics and varargs. The @SafeVarargs annotation is not available in Java 1.6, the minimum version for the driver.

Parameters:

boundary - The boundary positions for the polygon.

holes - The positions for the holes within the polygon.

Returns:

A GeoJSON Polygon document from the coordinates provided.

Throws:

IllegalArgumentException - If the line ring does not have at least 4 positions or the first and last positions are not equivalent.

See Also:

GeoJSON Polygon

add

protected static void add(ArrayBuilder coordinates,
       List<? extends Point2D> positions)

Adds a positions to the coordinates array.

Parameters:

coordinates - The array to add the position to.

positions - The positions to add.

add

protected static void add(ArrayBuilder coordinates,
       Point2D position)

Adds a position to the coordinates array.

Parameters:

coordinates - The array to add the position to.

position - The point to add.

addRaw

protected static void addRaw(ArrayBuilder arrayBuilder,
          Point2D position)

Adds the (x,y) coordinates from the point directly to the array provided.

Parameters:

arrayBuilder - The builder to append the (x,y) coordinates to.

position - The (x,y) coordinates.

lineRing

protected static void lineRing(ArrayBuilder positionArray,
            List<? extends Point2D> positions)
                        throws IllegalArgumentException

Fills in the LineRing coordinates.

Parameters:

positionArray - The array to fill with the positions.

positions - The positions defining the LineRing.

Throws:

IllegalArgumentException - If the line ring does not have at least 4 positions or the first and last positions are not equivalent.