Class WKTReader

Converts a Well-Known Text string to a Geometry.

The WKTReader allows extracting Geometry objects from either input streams or internal strings. This allows it to function as a parser to read Geometry objects from text blocks embedded in other data formats (e.g. XML).

The Well-known Text format is defined in the OpenGIS Simple Features Specification for SQL .

As of version 2.0, NTS can read WKT syntax which specifies coordinate dimension Z, M or ZM as modifiers(e.g.POINT Z) or in the name of the geometry type(e.g.LINESTRINGZM). If the coordinate dimension is specified it will be set in the created geometry. If the coordinate dimension is not specified, the default behaviour is to create XYZ geometry(this is backwards compatible with older JTS versions). This can be altered to create XY geometry by setting IsOldNtsCoordinateSyntaxAllowed to false.

A reader can be set to ensure the input is structurally valid by setting FixStructure to true. This ensures that geometry can be constructed without errors due to missing coordinates. The created geometry may still be topologically invalid.

NOTE: There is an inconsistency in the SFS. The WKT grammar states that MultiPoints are represented by MULTIPOINT ( ( x y), (x y) ), but the examples show MultiPoints as MULTIPOINT ( x y, x y ). Other implementations follow the latter syntax, so NTS will adopt it as well. A WKTReader is parameterized by a GeometryFactory, to allow it to create Geometry objects of the appropriate implementation. In particular, the GeometryFactory will determine the PrecisionModel and SRID that is used. The WKTReader will convert the input numbers to the precise internal representation. WKTReader reads also non-standard LINEARRING tags.

Inheritance

object

WKTReader

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: NetTopologySuite.IO

Assembly: NetTopologySuite.dll

Syntax

public class WKTReader

Constructors

WKTReader()

Creates a WKTReader that creates objects using a basic GeometryFactory.

Declaration

public WKTReader()

WKTReader(GeometryFactory)

Creates a WKTReader that creates objects using the given GeometryFactory.

Declaration

[Obsolete("Use a constructor with a configured NtsGeometryServices instance.")]
public WKTReader(GeometryFactory factory)

Parameters

Type	Name	Description
GeometryFactory	factory	The factory used to create Geometrys.

WKTReader(NtsGeometryServices)

Creates a WKTReader that creates objects using a basic GeometryFactory.

Declaration

public WKTReader(NtsGeometryServices ntsGeometryServices)

Parameters

Type	Name	Description
NtsGeometryServices	ntsGeometryServices

Properties

DefaultSRID

Gets or sets the default SRID

Declaration

[Obsolete("Supply an appropriate NtsGeometryServices instance to the constructor instead.  The ability to set this value after an instance is created may be removed in a future release.")]
public int DefaultSRID { get; set; }

Property Value

Type	Description
int

Factory

Gets or sets the factory to create geometries

Declaration

[Obsolete("Supply an appropriate NtsGeometryServices instance to the constructor instead.  The ability to set this value after an instance is created may be removed in a future release.")]
public GeometryFactory Factory { get; set; }

Property Value

Type	Description
GeometryFactory

FixStructure

Gets or sets a flag indicating that the structure of input geometry should be fixed so that the geometry can be constructed without error.
This involves adding coordinates if the input coordinate sequence is shorter than required.

Declaration

public bool FixStructure { get; set; }

Property Value

Type	Description
bool

See Also

MinimumValidSize

IsOldNtsCoordinateSyntaxAllowed

Gets or sets a value indicating whether or not coordinates may have 3 ordinate values even though no Z or M ordinate indicator is present. The default value is true.

Declaration

public bool IsOldNtsCoordinateSyntaxAllowed { get; set; }

Property Value

Type	Description
bool

IsOldNtsMultiPointSyntaxAllowed

Gets or sets a value indicating whether or not point coordinates in a MultiPoint geometry must not be enclosed in paren. The default value is true.

Declaration

public bool IsOldNtsMultiPointSyntaxAllowed { get; set; }

Property Value

Type	Description
bool

IsStrict

Gets or sets a value indicating if the reader should attempt to repair malformed input.

Declaration

public bool IsStrict { get; set; }

Property Value

Type	Description
bool

Remarks

Malformed in this case means the ring has too few points (4), or is not closed.

Methods

Read(Stream)

Converts a Well-known Text representation to a Geometry.

Declaration

public Geometry Read(Stream stream)

Parameters

Type	Name	Description
Stream	stream	one or more Geometry Tagged Text strings (see the OpenGIS Simple Features Specification) separated by whitespace.

Returns

Type	Description
Geometry	A Geometry specified by wellKnownText

Read(TextReader)

Converts a Well-known Text representation to a Geometry.

Declaration

public Geometry Read(TextReader reader)

Parameters

Type	Name	Description
TextReader	reader	A Reader which will return a "Geometry Tagged Text" string (see the OpenGIS Simple Features Specification).

Returns

Type	Description
Geometry	A Geometry read from reader.

Read(string)

Converts a Well-known Text representation to a Geometry.

Declaration

public Geometry Read(string wellKnownText)

Parameters

Type	Name	Description
string	wellKnownText	one or more Geometry Tagged Text strings (see the OpenGIS Simple Features Specification) separated by whitespace.

Returns

Type	Description
Geometry	A Geometry specified by wellKnownText