The abstract base class for all geometries.

abstract class Geometry {

 int _srid;

 /**
  * Creates a geometry from the WKT string [wkt].
  *
  * Throws a [WKTError] if [wkt] isn't a valid WKT geometry.
  */
 factory Geometry.wkt(String wkt) => parseWKT(wkt);


 /**
  * Creates a geometry from a GeoJSON string [json].
  *
  * Throws a  [FormatError] if [json] isn't valid.
  */
 factory Geometry.geojson(String json) => parseGeoJson(json);

 Geometry();

 /**
  * Returns 1 true if this geometric object is the empty Geometry.
  */
 @specification(name:"isEmpty()")
 bool get isEmpty;

 /**
  * Returns true if this geometric object has z coordinate values.
  */
 @specification(name:"is3D()")
 bool get is3D;

 /**
  * Returns true if this geometric object has m coordinate values.
  */
 @specification(name:"isMeasured()")
 bool get isMeasured;

 /**
  * Returns the closure of the combinatorial boundary of this geometric object
  */
 @specification(name:"boundary()")
 Geometry get boundary;

 /**
  *  Returns true if this geometric object has no anomalous geometric points,
  *  such as self intersection or self tangency.
  */
 @specification(name:"isSimple()")
 bool get isSimple;

 /**
  * Returns the name of the instantiable subtype of Geometry of which this
  * geometric object is an instantiable member. The name of the subtype of
  * Geometry is returned as a string.
  */
 @specification(name:"geometryType()")
 String get geometryType;

 /**
  * The inherent dimension of this geometric object, which must be less than
  * or equal to the coordinate dimension. In non-homogeneous collections,
  * this will return the largest topological dimension of the contained objects.
  */
 @specification(name:"dimension()")
 int get dimension;

 /**
  * Returns the Spatial Reference System ID for this geometric object.
  */
 @specification(name:"srid()")
 int get SRID => _srid;

 /**
  * the Spatial Reference System ID for this geometric object.
  */
 set SRID(int value) => _srid = value;

 _Envelope get _envelope {
   if (_cachedEnvelope == null) {
     _cachedEnvelope = _computeEnvelope();
   }
   return _cachedEnvelope;
 }

 _Envelope _cachedEnvelope;
 _Envelope _computeEnvelop();

 /**
  * A WKT representation of the geometry
  */
 @specification(name:"asText()")
 String get asText {
   var buffer = new StringBuffer();
   var writer = new _WKTWriter(buffer);
   _writeTaggedWKT(writer, withZ: is3D, withM: isMeasured);
   return buffer.toString();
 }

 _writeTaggedWKT(writer, {bool withZ: false, bool withM: false});
}