Class GeometryPrecisionReducer
- java.lang.Object
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- org.locationtech.jts.precision.GeometryPrecisionReducer
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public class GeometryPrecisionReducer extends java.lang.Object
Reduces the precision of aGeometry
according to the suppliedPrecisionModel
, ensuring that the result is valid (unless specified otherwise).By default the reduced result is topologically valid (i.e.
Geometry.isValid()
is true). To ensure this a polygonal geometry is reduced in a topologically valid fashion (technically, by using snap-rounding). Note that this may change polygonal geometry structure (e.g. two polygons separated by a distance below the specified precision will be merged into a single polygon).In general input must be valid geometry, or an
IllegalArgumentException
will be thrown. However if the invalidity is "mild" or very small then it may be eliminated by precision reduction.Alternatively, geometry can be reduced pointwise by using
setPointwise(boolean)
. In this case the result geometry topology may be invalid. Linear and point geometry are always reduced pointwise (i.e. without further change to topology or structure), since this does not change validity.By default the geometry precision model is not changed. This can be overridden by using
setChangePrecisionModel(boolean)
.Normally collapsed components (e.g. lines collapsing to a point) are not included in the result. This behavior can be changed by using
setRemoveCollapsedComponents(boolean)
.- Version:
- 1.12
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Constructor Summary
Constructors Constructor Description GeometryPrecisionReducer(PrecisionModel pm)
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description Geometry
reduce(Geometry geom)
Reduces the precision of a geometry, according to the specified strategy of this reducer.static Geometry
reduce(Geometry g, PrecisionModel precModel)
Convenience method for doing precision reduction on a single geometry, with collapses removed and keeping the geometry precision model the same, and preserving polygonal topology.static Geometry
reducePointwise(Geometry g, PrecisionModel precModel)
Convenience method for doing pointwise precision reduction on a single geometry, with collapses removed and keeping the geometry precision model the same, but NOT preserving valid polygonal topology.void
setChangePrecisionModel(boolean changePrecisionModel)
Sets whether thePrecisionModel
of the new reduced Geometry will be changed to be thePrecisionModel
supplied to specify the precision reduction.void
setPointwise(boolean isPointwise)
Sets whether the precision reduction will be done in pointwise fashion only.void
setRemoveCollapsedComponents(boolean removeCollapsed)
Sets whether the reduction will result in collapsed components being removed completely, or simply being collapsed to an (invalid) Geometry of the same type.
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Constructor Detail
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GeometryPrecisionReducer
public GeometryPrecisionReducer(PrecisionModel pm)
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Method Detail
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reduce
public static Geometry reduce(Geometry g, PrecisionModel precModel)
Convenience method for doing precision reduction on a single geometry, with collapses removed and keeping the geometry precision model the same, and preserving polygonal topology.- Parameters:
g
- the geometry to reduceprecModel
- the precision model to use- Returns:
- the reduced geometry
- Throws:
java.lang.IllegalArgumentException
- if the reduction fails due to invalid input geometry is invalid
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reducePointwise
public static Geometry reducePointwise(Geometry g, PrecisionModel precModel)
Convenience method for doing pointwise precision reduction on a single geometry, with collapses removed and keeping the geometry precision model the same, but NOT preserving valid polygonal topology.- Parameters:
g
- the geometry to reduceprecModel
- the precision model to use- Returns:
- the reduced geometry
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setRemoveCollapsedComponents
public void setRemoveCollapsedComponents(boolean removeCollapsed)
Sets whether the reduction will result in collapsed components being removed completely, or simply being collapsed to an (invalid) Geometry of the same type. The default is to remove collapsed components.- Parameters:
removeCollapsed
- iftrue
collapsed components will be removed
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setChangePrecisionModel
public void setChangePrecisionModel(boolean changePrecisionModel)
Sets whether thePrecisionModel
of the new reduced Geometry will be changed to be thePrecisionModel
supplied to specify the precision reduction.The default is to not change the precision model
- Parameters:
changePrecisionModel
- iftrue
the precision model of the created Geometry will be the the precisionModel supplied in the constructor.
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setPointwise
public void setPointwise(boolean isPointwise)
Sets whether the precision reduction will be done in pointwise fashion only. Pointwise precision reduction reduces the precision of the individual coordinates only, but does not attempt to recreate valid topology. This is only relevant for geometries containing polygonal components.- Parameters:
isPointwise
- if reduction should be done pointwise only
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reduce
public Geometry reduce(Geometry geom)
Reduces the precision of a geometry, according to the specified strategy of this reducer.- Parameters:
geom
- the geometry to reduce- Returns:
- the precision-reduced geometry
- Throws:
java.lang.IllegalArgumentException
- if the reduction fails due to invalid input geometry is invalid
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