Class WKBWriter
- java.lang.Object
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- org.locationtech.jts.io.WKBWriter
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public class WKBWriter extends java.lang.Object
Writes aGeometry
into Well-Known Binary format. Supports use of anOutStream
, which allows easy use with arbitrary byte stream sinks.The WKB format is specified in the OGC Simple Features for SQL specification. This implementation also supports the Extended WKB standard. Extended WKB allows writing 3-dimensional coordinates and including the geometry SRID value. The presence of 3D coordinates is signified by setting the high bit of the wkbType word. The presence of an SRID is signified by setting the third bit of the wkbType word. EWKB format is upward compatible with the original SFS WKB format.
Empty Points cannot be represented in WKB; an
IllegalArgumentException
will be thrown if one is written.The WKB specification does not support representing
LinearRing
s; they will be written asLineString
s.This class is designed to support reuse of a single instance to read multiple geometries. This class is not thread-safe; each thread should create its own instance.
Syntax
The following syntax specification describes the version of Well-Known Binary supported by JTS.The specification uses a syntax language similar to that used in the C language. Bitfields are specified from hi-order to lo-order bits.
byte = 1 byte uint32 = 32 bit unsigned integer (4 bytes) double = double precision number (8 bytes) abstract Point { } Point2D extends Point { double x; double y; } Point3D extends Point { double x; double y; double z; } LinearRing { uint32 numPoints; Point points[numPoints]; } enum wkbGeometryType { wkbPoint = 1, wkbLineString = 2, wkbPolygon = 3, wkbMultiPoint = 4, wkbMultiLineString = 5, wkbMultiPolygon = 6, wkbGeometryCollection = 7 } enum byteOrder { wkbXDR = 0, // Big Endian wkbNDR = 1 // Little Endian } WKBType { uint32 wkbGeometryType : 8; // values from enum wkbGeometryType } EWKBType { uint32 is3D : 1; // 0 = 2D, 1 = 3D uint32 noData1 : 1; uint32 hasSRID : 1; // 0, no, 1 = yes uint32 noData2 : 21; uint32 wkbGeometryType : 8; // values from enum wkbGeometryType } abstract WKBGeometry { byte byteOrder; // values from enum byteOrder EWKBType wkbType [ uint32 srid; ] // only if hasSRID = yes } WKBPoint extends WKBGeometry { Point point; } WKBLineString extends WKBGeometry { uint32 numCoords; Point points[numCoords]; } WKBPolygon extends WKBGeometry { uint32 numRings; LinearRing rings[numRings]; } WKBMultiPoint extends WKBGeometry { uint32 numElems; WKBPoint elems[numElems]; } WKBMultiLineString extends WKBGeometry { uint32 numElems; WKBLineString elems[numElems]; } wkbMultiPolygon extends WKBGeometry { uint32 numElems; WKBPolygon elems[numElems]; } WKBGeometryCollection extends WKBGeometry { uint32 numElems; WKBGeometry elems[numElems]; }
- See Also:
WKBReader
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Constructor Summary
Constructors Constructor Description WKBWriter()
Creates a writer that writesGeometry
s with output dimension = 2 and BIG_ENDIAN byte orderWKBWriter(int outputDimension)
Creates a writer that writesGeometry
s with the given dimension (2 or 3) for output coordinates andByteOrderValues.BIG_ENDIAN
byte order.WKBWriter(int outputDimension, boolean includeSRID)
Creates a writer that writesGeometry
s with the given dimension (2 or 3) for output coordinates andByteOrderValues.BIG_ENDIAN
byte order.WKBWriter(int outputDimension, int byteOrder)
Creates a writer that writesGeometry
s with the given dimension (2 or 3) for output coordinates and byte order If the input geometry has a small coordinate dimension, coordinates will be padded withCoordinate.NULL_ORDINATE
.WKBWriter(int outputDimension, int byteOrder, boolean includeSRID)
Creates a writer that writesGeometry
s with the given dimension (2 or 3) for output coordinates and byte order.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description static java.lang.String
bytesToHex(byte[] bytes)
Deprecated.static java.lang.String
toHex(byte[] bytes)
Converts a byte array to a hexadecimal string.byte[]
write(Geometry geom)
Writes aGeometry
into a byte array.void
write(Geometry geom, OutStream os)
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Constructor Detail
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WKBWriter
public WKBWriter()
Creates a writer that writesGeometry
s with output dimension = 2 and BIG_ENDIAN byte order
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WKBWriter
public WKBWriter(int outputDimension)
Creates a writer that writesGeometry
s with the given dimension (2 or 3) for output coordinates andByteOrderValues.BIG_ENDIAN
byte order. If the input geometry has a small coordinate dimension, coordinates will be padded withCoordinate.NULL_ORDINATE
.- Parameters:
outputDimension
- the coordinate dimension to output (2 or 3)
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WKBWriter
public WKBWriter(int outputDimension, boolean includeSRID)
Creates a writer that writesGeometry
s with the given dimension (2 or 3) for output coordinates andByteOrderValues.BIG_ENDIAN
byte order. This constructor also takes a flag to control whether srid information will be written. If the input geometry has a smaller coordinate dimension, coordinates will be padded withCoordinate.NULL_ORDINATE
.- Parameters:
outputDimension
- the coordinate dimension to output (2 or 3)includeSRID
- indicates whether SRID should be written
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WKBWriter
public WKBWriter(int outputDimension, int byteOrder)
Creates a writer that writesGeometry
s with the given dimension (2 or 3) for output coordinates and byte order If the input geometry has a small coordinate dimension, coordinates will be padded withCoordinate.NULL_ORDINATE
.- Parameters:
outputDimension
- the coordinate dimension to output (2 or 3)byteOrder
- the byte ordering to use
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WKBWriter
public WKBWriter(int outputDimension, int byteOrder, boolean includeSRID)
Creates a writer that writesGeometry
s with the given dimension (2 or 3) for output coordinates and byte order. This constructor also takes a flag to control whether srid information will be written. If the input geometry has a small coordinate dimension, coordinates will be padded withCoordinate.NULL_ORDINATE
.- Parameters:
outputDimension
- the coordinate dimension to output (2 or 3)byteOrder
- the byte ordering to useincludeSRID
- indicates whether SRID should be written
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Method Detail
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bytesToHex
public static java.lang.String bytesToHex(byte[] bytes)
Deprecated.Converts a byte array to a hexadecimal string.- Parameters:
bytes
-- Returns:
- a string of hexadecimal digits
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toHex
public static java.lang.String toHex(byte[] bytes)
Converts a byte array to a hexadecimal string.- Parameters:
bytes
- a byte array- Returns:
- a string of hexadecimal digits
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write
public byte[] write(Geometry geom)
Writes aGeometry
into a byte array.- Parameters:
geom
- the geometry to write- Returns:
- the byte array containing the WKB
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