Module org.apache.sis.referencing

Package org.apache.sis.geometry

Class GeneralEnvelope

Object

FormattableObject

AbstractEnvelope

GeneralEnvelope

All Implemented Interfaces:

Serializable, Cloneable, Emptiable, Envelope

public class GeneralEnvelope
extends AbstractEnvelope
implements Cloneable, Serializable

A mutable Envelope (a minimum bounding box or rectangle) of arbitrary dimension. Regardless of dimension, an Envelope can be represented without ambiguity as two direct positions (coordinate tuples). To encode an Envelope, it is sufficient to encode these two points.

Envelope uses an arbitrary Coordinate Reference System, which does not need to be geographic. This is different than the Geographic­Bounding­Box class provided in the metadata package, which can be used as a kind of envelope restricted to a Geographic CRS having Greenwich prime meridian.

This particular implementation of Envelope is said "General" because it uses coordinates of an arbitrary number of dimensions. This is in contrast with Envelope2D, which can use only two-dimensional coordinates.

A General­Envelope can be created in various ways:

• From a given number of dimension, with all coordinates initialized to 0.
• From two coordinate tuples.
• From a another envelope (copy constructor).
• From a geographic bounding box.
• From a character sequence representing a BBOX or a Well Known Text (WKT) format.

Crossing the anti-meridian of a Geographic CRS

The Web Coverage Service (WCS) specification authorizes (with special treatment) cases where upper < lower at least in the longitude case. They are envelopes crossing the anti-meridian, like the red box below (the green box is the usual case). The default implementation of methods listed in the right column can handle such cases.

Supported methods:

• Abstract­Envelope.get­Minimum(int)
• Abstract­Envelope.get­Maximum(int)
• Abstract­Envelope.get­Median(int)
• Abstract­Envelope.get­Span(int)
• Abstract­Envelope.is­Empty()
• to­Simple­Envelopes()
• contains(Direct­Position)
• contains(Envelope)
• intersects(Envelope)
• intersect(Envelope)
• add(Envelope)
• add(Direct­Position)

Envelope validation

If and only if this envelope is associated to a non-null CRS, then constructors and setter methods in this class perform the following checks:

• The number of CRS dimensions must be equal to this.Envelope.get­Dimension().
• For each dimension i, get­Lower(i) > get­Upper(i) is allowed only if the coordinate system axis range meaning is WRAPAROUND.

Note that this class does not require the coordinate values to be between the axis minimum and maximum values. This flexibility exists because out-of-range values happen in practice, while they do not hurt the working of add(…), intersect(…), contains(…) and similar methods. This in contrast with the lower > upper case, which cause the above-cited methods to behave in an unexpected way if the axis does not have wraparound range meaning.

Since:

0.3

See Also:

• Envelope2D
• Default­Geographic­Bounding­Box
• Serialized Form

Constructor Summary

Constructors

Constructor	Description
General­Envelope(double[] lower­Corner, double[] upper­Corner)	Constructs an envelope defined by two corners given as sequences of coordinate values.
General­Envelope(int dimension)	Constructs an empty envelope of the specified dimension.
General­Envelope(Char­Sequence wkt)	Constructs a new envelope initialized to the values parsed from the given string in BOX or Well Known Text (WKT) format.
General­Envelope(Direct­Position lower­Corner, Direct­Position upper­Corner)	Constructs an envelope defined by two corners given as direct positions.
General­Envelope(Envelope envelope)	Constructs a new envelope with the same data than the specified envelope.
General­Envelope(Geographic­Bounding­Box box)	Constructs a new envelope with the same data than the specified geographic bounding box.
General­Envelope(Coordinate­Reference­System crs)	Constructs an empty envelope with the specified coordinate reference system.

Method Summary

Modifier and Type	Method	Description
void	add(Direct­Position position)	Adds a point to this envelope.
void	add(Envelope envelope)	Adds an envelope object to this envelope.
static General­Envelope	cast­Or­Copy(Envelope envelope)	Returns the given envelope as a General­Envelope instance.
General­Envelope	clone()	Returns a deep copy of this envelope.
boolean	equals(Object object)	Returns true if the specified object is an envelope of the same class with equals coordinates and CRS.
Coordinate­Reference­System	get­Coordinate­Reference­System()	Returns the envelope coordinate reference system, or null if unknown.
int	get­Dimension()	Returns the length of coordinate sequence (the number of entries) in this envelope.
double	get­Lower(int dimension)	Returns the limit in the direction of decreasing coordinate values in the specified dimension.
double	get­Maximum(int dimension)	Returns the maximal coordinate value for the specified dimension.
double	get­Median(int dimension)	Returns the median coordinate along the specified dimension.
double	get­Minimum(int dimension)	Returns the minimal coordinate value for the specified dimension.
double	get­Span(int dimension)	Returns the envelope span (typically width or height) along the specified dimension.
double	get­Upper(int dimension)	Returns the limit in the direction of increasing coordinate values in the specified dimension.
int	hash­Code()	Returns a hash value for this envelope.
General­Envelope	horizontal()	Returns a view over the two horizontal dimensions of this envelope.
void	intersect(Envelope envelope)	Sets this envelope to the intersection of this envelope with the specified one.
boolean	is­All­Na­N()	Returns false if at least one coordinate value is not NaN.
boolean	is­Empty()	Determines whether or not this envelope is empty.
boolean	normalize()	Ensures that the envelope is contained inside the coordinate system domain.
void	set­Coordinate­Reference­System(Coordinate­Reference­System crs)	Sets the coordinate reference system in which the coordinate are given.
void	set­Envelope(double... corners)	Sets the envelope to the specified values, which must be the lower corner coordinates followed by upper corner coordinates.
void	set­Envelope(Envelope envelope)	Sets this envelope to the same coordinate values than the specified envelope.
void	set­Range(int dimension, double lower, double upper)	Sets the envelope range along the specified dimension.
boolean	set­Time­Range(Instant start­Time, Instant end­Time)	If this envelope has a temporal component, sets its temporal dimension to the given range.
void	set­To­Infinite()	Sets the lower corner to negative infinity and the upper corner to positive infinity.
void	set­To­Na­N()	Sets all coordinate values to NaN.
boolean	simplify()	Ensures that lower ≤ upper for every dimensions.
General­Envelope	sub­Envelope(int begin­Index, int end­Index)	Returns a view over this envelope that encompass only some dimensions.
String	to­String()	Formats this envelope as a "BOX" element.
void	translate(double... vector)	Translates the envelope by the given vector.
boolean	wraparound(Wraparound­Method method)	If this envelope is crossing the limit of a wraparound axis, modifies coordinates by application of the specified strategy.

Methods inherited from class AbstractEnvelope

contains, contains, contains, equals, format­To, get­Lower­Corner, get­Median, get­Span, get­Time­Range, get­Upper­Corner, intersects, intersects, is­Finite, to­Simple­Envelopes

Methods inherited from class FormattableObject

print, to­String, to­WKT

Methods inherited from class Object

finalize, get­Class, notify, notify­All, wait, wait, wait

Constructor Details

GeneralEnvelope

public GeneralEnvelope(DirectPosition lowerCorner,
 DirectPosition upperCorner)
                throws MismatchedDimensionException,
MismatchedReferenceSystemException

Constructs an envelope defined by two corners given as direct positions. If at least one corner is associated to a CRS, then the new envelope will also be associated to that CRS.

Parameters:

lower­Corner - the limits in the direction of decreasing coordinate values for each dimension.

upper­Corner - the limits in the direction of increasing coordinate values for each dimension.

Throws:

Mismatched­Dimension­Exception - if the two positions do not have the same dimension.

Mismatched­Reference­System­Exception - if the CRS of the two position are not equal.

GeneralEnvelope

public GeneralEnvelope(double[] lowerCorner,
 double[] upperCorner)
                throws MismatchedDimensionException

Constructs an envelope defined by two corners given as sequences of coordinate values. The Coordinate Reference System is initially null.

Parameters:

lower­Corner - the limits in the direction of decreasing coordinate values for each dimension.

upper­Corner - the limits in the direction of increasing coordinate values for each dimension.

Throws:

Mismatched­Dimension­Exception - if the two sequences do not have the same length.

GeneralEnvelope

public GeneralEnvelope(int dimension)

Constructs an empty envelope of the specified dimension. All coordinates are initialized to 0 and the coordinate reference system is undefined.

Parameters:

dimension - the envelope dimension.

GeneralEnvelope

public GeneralEnvelope(CoordinateReferenceSystem crs)

Constructs an empty envelope with the specified coordinate reference system. All coordinate values are initialized to 0.

Parameters:

crs - the coordinate reference system.

GeneralEnvelope

public GeneralEnvelope(Envelope envelope)

Constructs a new envelope with the same data than the specified envelope.

Parameters:

envelope - the envelope to copy.

See Also:

• cast­Or­Copy(Envelope)

GeneralEnvelope

public GeneralEnvelope(GeographicBoundingBox box)

Constructs a new envelope with the same data than the specified geographic bounding box. The coordinate reference system is set to the default geographic CRS. Axis order is (longitude, latitude).

Parameters:

box - the bounding box to copy.

GeneralEnvelope

public GeneralEnvelope(CharSequence wkt)
                throws IllegalArgumentException

Constructs a new envelope initialized to the values parsed from the given string in BOX or Well Known Text (WKT) format. The given string is typically a BOX element like below:

BOX(-180 -90, 180 90)

However, this constructor is lenient to other geometry types like POLYGON. Actually this constructor ignores the geometry type and just applies the following simple rules:

• Character sequences complying to the rules of Java identifiers are skipped.
• Coordinates are separated by a coma (,) character.
• The coordinates in a coordinate tuple are separated by a space.
• Coordinate numbers are assumed formatted in US locale.
• The coordinate having the highest dimension determines the dimension of this envelope.

This constructor does not check the consistency of the provided text. For example, it does not check that every points in a LINESTRING have the same dimension. However, this constructor ensures that the parenthesis are balanced, in order to catch some malformed WKT.

Example

The following texts can be parsed by this constructor in addition of the usual BOX element. This constructor creates the bounding box of those geometries:

• POINT(6 10)
• MULTIPOLYGON(((1 1, 5 1, 1 5, 1 1),(2 2, 3 2, 3 3, 2 2)))
• GEOMETRYCOLLECTION(POINT(4 6),LINESTRING(3 8,7 10))

Parameters:

wkt - the BOX, POLYGON or other kind of element to parse.

Throws:

Illegal­Argument­Exception - if the given string cannot be parsed.

See Also:

• Envelopes.from­WKT(Char­Sequence)
• Envelopes.to­String(Envelope)

Method Details

castOrCopy

public static GeneralEnvelope castOrCopy(Envelope envelope)

Returns the given envelope as a General­Envelope instance. If the given envelope is already an instance of General­Envelope, then it is returned unchanged. Otherwise the coordinate values and the CRS of the given envelope are copied in a new General­Envelope.

Parameters:

envelope - the envelope to cast, or null.

Returns:

the values of the given envelope as a General­Envelope instance.

See Also:

• Abstract­Envelope.cast­Or­Copy(Envelope)
• Immutable­Envelope.cast­Or­Copy(Envelope)

setCoordinateReferenceSystem

public void setCoordinateReferenceSystem(CoordinateReferenceSystem crs)
                                  throws MismatchedDimensionException

Sets the coordinate reference system in which the coordinate are given. This method does not reproject the envelope, and does not check if the envelope is contained in the new domain of validity.

If the envelope coordinates need to be transformed to the new CRS, consider using Envelopes.transform(Envelope, Coordinate­Reference­System) instead.

Parameters:

crs - the new coordinate reference system, or null.

Throws:

Mismatched­Dimension­Exception - if the specified CRS doesn't have the expected number of dimensions.

Illegal­State­Exception - if a range of coordinate values in this envelope is compatible with the given CRS. See Envelope validation in class javadoc for more details.

setRange

public void setRange(int dimension,
 double lower,
 double upper)
              throws IndexOutOfBoundsException

Sets the envelope range along the specified dimension.

Parameters:

dimension - the dimension to set.

lower - the limit in the direction of decreasing coordinate values.

upper - the limit in the direction of increasing coordinate values.

Throws:

Index­Out­Of­Bounds­Exception - if the given index is out of bounds.

Illegal­Argument­Exception - if lower > upper and the axis range meaning at the given dimension is not "wraparound". See Envelope validation in class javadoc for more details.

setEnvelope

public void setEnvelope(double... corners)

Sets the envelope to the specified values, which must be the lower corner coordinates followed by upper corner coordinates. The number of arguments provided shall be twice this envelope dimension, and minimum shall not be greater than maximum.

Example: (x_min, y_min, z_min, x_max, y_max, z_max)

Parameters:

corners - coordinates of the new lower corner followed by the new upper corner.

setEnvelope

public void setEnvelope(Envelope envelope)
                 throws MismatchedDimensionException

Sets this envelope to the same coordinate values than the specified envelope. If the given envelope has a non-null Coordinate Reference System (CRS), then the CRS of this envelope will be set to the CRS of the given envelope.

Parameters:

envelope - the envelope to copy coordinates from.

Throws:

Mismatched­Dimension­Exception - if the specified envelope does not have the expected number of dimensions.

setToInfinite

public void setToInfinite()

Sets the lower corner to negative infinity and the upper corner to positive infinity. The coordinate reference system (if any) stay unchanged.

setToNaN

public void setToNaN()

Sets all coordinate values to NaN. The coordinate reference system (if any) stay unchanged.

See Also:

• Abstract­Envelope.is­All­Na­N()

setTimeRange

public boolean setTimeRange(Instant startTime,
 Instant endTime)

If this envelope has a temporal component, sets its temporal dimension to the given range. Otherwise this method does nothing. This convenience method converts the given instants to floating point values using Default­Temporal­CRS, then delegates to set­Range(int, double, double).

Null value means no time limit. More specifically null start­Time is mapped to −∞ and null end­Time is mapped to +∞. This rule makes easy to create is before or is after temporal filters, which can be combined with other envelopes using intersection for logical AND, or union for logical OR operations.

Parameters:

start­Time - the lower temporal value, or null if unbounded.

end­Time - the upper temporal value, or null if unbounded.

Returns:

whether the temporal component has been set, or false if no temporal dimension has been found in this envelope.

Since:

1.0

See Also:

• Abstract­Envelope.get­Time­Range()
• Envelopes.to­Time­Range(Envelope)

translate

public void translate(double... vector)

Translates the envelope by the given vector. For every dimension i, the lower and upper values are increased by vector[i].

This method does not check if the translation result is inside the coordinate system domain (e.g. [-180 … +180]° of longitude). Callers can normalize the envelope when desired by call to the normalize() method.

Parameters:

vector - the translation vector. The length of this array shall be equal to this envelope dimension.

Since:

0.5

add

public void add(DirectPosition position)
         throws MismatchedDimensionException

Adds a point to this envelope. The resulting envelope is the smallest envelope that contains both the original envelope and the specified point.

After adding a point, a call to contains(Direct­Position) with the added point as an argument will return true, except if one of the point coordinates was Double.Na­N in which case the corresponding coordinate has been ignored.

Preconditions

This method assumes that the specified point uses a CRS equivalent to this envelope CRS. For performance reasons, it will no be verified unless Java assertions are enabled.

Crossing the anti-meridian of a Geographic CRS

This method supports envelopes crossing the anti-meridian. In such cases it is possible to move both envelope borders in order to encompass the given point, as illustrated below (the new point is represented by the + symbol):

    ─────┐   + ┌─────
    ─────┘     └─────

The default implementation moves only the border which is closest to the given point.

Parameters:

position - the point to add.

Throws:

Mismatched­Dimension­Exception - if the given point does not have the expected number of dimensions.

Assertion­Error - if assertions are enabled and the envelopes have mismatched CRS.

add

public void add(Envelope envelope)
         throws MismatchedDimensionException

Adds an envelope object to this envelope. The resulting envelope is the union of the two Envelope objects.

Preconditions

This method assumes that the specified envelope uses a CRS equivalent to this envelope CRS. For performance reasons, it will no be verified unless Java assertions are enabled.

Crossing the anti-meridian of a Geographic CRS

This method supports envelopes crossing the anti-meridian. If one or both envelopes cross the anti-meridian, then the result of the add operation may be an envelope expanding to infinities. In such case, the coordinate range will be either [−∞…∞] or [0…−0] depending on whatever the original range crosses the anti-meridian or not.

Handling of NaN values

Double.Na­N values may be present in any dimension, in the lower coordinate, upper coordinate or both. The behavior of this method in such case depends where the Na­N values appear and whether an envelope spans the anti-meridian:

• If this envelope or the given envelope spans anti-meridian in the dimension containing Na­N coordinates, then this method does not changes the coordinates in that dimension. The rational for such conservative approach is because union computation depends on whether the other envelope spans anti-meridian too, which is unknown because at least one envelope bounds is Na­N. Since anti-meridian crossing has been detected in an envelope, there is suspicion about whether the other envelope could cross anti-meridian too.
• Otherwise since the envelope containing real values does not cross anti-meridian in that dimension, this method assumes that the envelope containing Na­N values does not cross anti-meridian neither. This assumption is not guaranteed to be true, but cover common cases. With this assumption in mind:
  • All Na­N coordinates in the given envelope are ignored, i.e. this method does not replace finite coordinates in this envelope by Na­N values from the given envelope. Note that if only the lower or upper bound is Na­N, the other bound will still be used for computing union with the assumption described in above paragraph.
  • All Na­N coordinates in this envelope are left unchanged, i.e. the union will still contain all the Na­N values that this envelope had before add(Envelope) invocation. Note that if only the lower or upper bound is Na­N, the other bound will still be used for computing union with the assumption described in above paragraph.

Parameters:

envelope - the Envelope to add to this envelope.

Throws:

Mismatched­Dimension­Exception - if the given envelope does not have the expected number of dimensions.

Assertion­Error - if assertions are enabled and the envelopes have mismatched CRS.

See Also:

• Envelopes.union(Envelope...)
• Default­Geographic­Bounding­Box.add(Geographic­Bounding­Box)

intersect

public void intersect(Envelope envelope)
               throws MismatchedDimensionException

Sets this envelope to the intersection of this envelope with the specified one.

Preconditions

This method assumes that the specified envelope uses a CRS equivalent to this envelope CRS. For performance reasons, it will no be verified unless Java assertions are enabled.

Crossing the anti-meridian of a Geographic CRS

This method supports envelopes crossing the anti-meridian.

Handling of NaN values

Double.Na­N values may be present in any dimension, in the lower coordinate, upper coordinate or both. The behavior of this method in such case depends where the Na­N values appear and whether an envelope spans the anti-meridian:

• If this envelope or the given envelope spans anti-meridian in the dimension containing Na­N coordinates, then this method does not changes the coordinates in that dimension. The rational for such conservative approach is because intersection computation depends on whether the other envelope spans anti-meridian too, which is unknown because at least one envelope bounds is Na­N. Since anti-meridian crossing has been detected in an envelope, there is suspicion about whether the other envelope could cross anti-meridian too.
• Otherwise since the envelope containing real values does not cross anti-meridian in that dimension, this method assumes that the envelope containing Na­N values does not cross anti-meridian neither. This assumption is not guaranteed to be true, but cover common cases. With this assumption in mind:
  • All Na­N coordinates in the given envelope are ignored, i.e. this method does not replace finite coordinates in this envelope by Na­N values from the given envelope. Note that if only the lower or upper bound is Na­N, the other bound will still be used for computing intersection with the assumption described in above paragraph.
  • All Na­N coordinates in this envelope are left unchanged, i.e. the intersection will still contain all the Na­N values that this envelope had before intersect(Envelope) invocation. Note that if only the lower or upper bound is Na­N, the other bound will still be used for computing intersection with the assumption described in above paragraph.

Double.Na­N coordinates may appear as a result of intersection, even if such values were not present in any source envelopes, if the two envelopes do not intersect in some dimensions.

Parameters:

envelope - the Envelope to intersect to this envelope.

Throws:

Mismatched­Dimension­Exception - if the given envelope does not have the expected number of dimensions.

Assertion­Error - if assertions are enabled and the envelopes have mismatched CRS.

See Also:

• Envelopes.intersect(Envelope...)
• Default­Geographic­Bounding­Box.intersect(Geographic­Bounding­Box)

normalize

public boolean normalize()

Ensures that the envelope is contained inside the coordinate system domain. For each dimension, this method compares the coordinate values against the limits of the coordinate system axis for that dimension. If some coordinates are out of range, then there is a choice depending on the axis range meaning:

• If Range­Meaning.EXACT (typically latitudes coordinates), then values greater than the axis maximal value are replaced by the axis maximum, and values smaller than the axis minimal value are replaced by the axis minimum.
• If Range­Meaning.WRAPAROUND (typically longitudes coordinates), then a multiple of the axis range (e.g. 360° for longitudes) is added or subtracted. Example:
  • the [190 … 200]° longitude range is converted to [-170 … -160]°,
  • the [170 … 200]° longitude range is converted to [+170 … -160]°.
  See Crossing the anti-meridian of a Geographic CRS in the class javadoc for more information about the meaning of such range.

Crossing the anti-meridian of a Geographic CRS

If the envelope is crossing the anti-meridian, then some lower coordinate values may become greater than their upper counterpart as a result of this method call. If such effect is undesirable, then this method may be combined with simplify() as below:

if (envelope.normalize()) {
    envelope.simplify();
}

Choosing the range of longitude values

Geographic CRS typically have longitude values in the [-180 … +180]° range, but the [0 … 360]° range is also occasionally used. Callers need to ensure that this envelope CRS is associated to axes having the desired minimum and maximum value.

Usage

This method is sometimes useful before to compute the union or intersection of envelopes, in order to ensure that both envelopes are defined in the same domain. This method may also be invoked before to project an envelope, since some projections produce Double.Na­N numbers when given an coordinate value out of bounds.

Returns:

true if this envelope has been modified as a result of this method call, or false if no change has been done.

See Also:

• Abstract­Direct­Position.normalize()
• Wraparound­Method.NORMALIZE

simplify

public boolean simplify()
                 throws IllegalStateException

Ensures that lower ≤ upper for every dimensions. If a upper coordinate value is less than a lower coordinate value, then there is a choice:

• If the axis has Range­Meaning.WRAPAROUND, then:
  • the lower coordinate value is set to the axis minimum value, and
  • the upper coordinate value is set to the axis maximum value.
• Otherwise an Illegal­State­Exception is thrown.

This method is useful when the envelope needs to be used with libraries that do not support envelopes crossing the anti-meridian.

Returns:

true if this envelope has been modified as a result of this method call, or false if no change has been done.

Throws:

Illegal­State­Exception - if a upper coordinate value is less than a lower coordinate value on an axis which does not have the WRAPAROUND range meaning.

See Also:

• Abstract­Envelope.to­Simple­Envelopes()
• Wraparound­Method.EXPAND

wraparound

public boolean wraparound(WraparoundMethod method)
                   throws IllegalStateException

If this envelope is crossing the limit of a wraparound axis, modifies coordinates by application of the specified strategy. This applies typically to longitude values crossing the anti-meridian, but other kinds of wraparound axes may also exist. Possible values are listed below.

Legal argument values

Value	Action
WraparoundMethod.NONE:	Do nothing and return false.
WraparoundMethod.NORMALIZE:	Delegate to normalize().
WraparoundMethod.EXPAND:	Equivalent to simplify().
WraparoundMethod.CONTIGUOUS:	See enumeration javadoc.
WraparoundMethod.CONTIGUOUS_LOWER:	See enumeration javadoc.
WraparoundMethod.CONTIGUOUS_UPPER:	See enumeration javadoc.
WraparoundMethod.SPLIT:	Throw Illegal­Argument­Exception.

Parameters:

method - the strategy to use for representing a region crossing the anti-meridian or other wraparound limit.

Returns:

true if this envelope has been modified as a result of this method call, or false if no change has been done.

Throws:

Illegal­State­Exception - if a upper coordinate value is less than a lower coordinate value on an axis which does not have the WRAPAROUND range meaning.

Since:

1.1

horizontal

public GeneralEnvelope horizontal()
                           throws IllegalStateException

Returns a view over the two horizontal dimensions of this envelope. The horizontal dimensions are inferred from the CRS. If this method cannot infer the horizontal dimensions, then an Illegal­State­Exception is thrown.

The returned envelope is a view: changes in the returned envelope are reflected in this envelope, and conversely. The returned envelope will have its CRS defined.

Returns:

a view over the horizontal components of this envelope. May be this.

Throws:

Illegal­State­Exception - if this method cannot infer the horizontal components of this envelope.

Since:

1.1

See Also:

• sub­Envelope(int, int)
• CRS.get­Horizontal­Component(Coordinate­Reference­System)

subEnvelope

public GeneralEnvelope subEnvelope(int beginIndex,
 int endIndex)
                            throws IndexOutOfBoundsException

Returns a view over this envelope that encompass only some dimensions. The returned object is "live": changes applied on the original envelope is reflected in the sub-envelope view, and conversely.

This method is useful for querying and updating only some dimensions. For example, in order to expand only the horizontal component of a four dimensional (x,y,z,t) envelope, one can use:

envelope.subEnvelope(0, 2).add(myPosition2D);

If the sub-envelope needs to be independent from the original envelope, use the following idiom:

GeneralEnvelope copy = envelope.subEnvelope(0, 2).clone();

The sub-envelope is initialized with a null CRS. This method does not compute a sub-CRS because it may not be needed, or the sub-CRS may be already known by the caller.

Parameters:

begin­Index - the index of the first valid coordinate value of the corners.

end­Index - the index after the last valid coordinate value of the corners.

Returns:

the sub-envelope of dimension end­Index - begin­Index.

Throws:

Index­Out­Of­Bounds­Exception - if an index is out of bounds.

See Also:

• horizontal()
• CRS.get­Component­At(Coordinate­Reference­System, int, int)

clone

public GeneralEnvelope clone()

Returns a deep copy of this envelope.

Overrides:

clone in class Object

Returns:

a clone of this envelope.

getDimension

public int getDimension()

Returns the length of coordinate sequence (the number of entries) in this envelope. This information is available even when the coordinate reference system is unknown.

Specified by:

get­Dimension in interface Envelope

Returns:

the dimensionality of this envelope.

getCoordinateReferenceSystem

public CoordinateReferenceSystem getCoordinateReferenceSystem()

Returns the envelope coordinate reference system, or null if unknown. If non-null, it shall be the same as lower corner and upper corner CRS.

Specified by:

get­Coordinate­Reference­System in interface Envelope

Returns:

the envelope CRS, or null if unknown.

getLower

public double getLower(int dimension)
                throws IndexOutOfBoundsException

Returns the limit in the direction of decreasing coordinate values in the specified dimension. This is usually the algebraic minimum, except if this envelope spans the anti-meridian.

Specified by:

get­Lower in class Abstract­Envelope

Parameters:

dimension - the dimension for which to obtain the coordinate value.

Returns:

the starting coordinate value at the given dimension.

Throws:

Index­Out­Of­Bounds­Exception - if the given index is negative or is equal or greater than the envelope dimension.

See Also:

• Abstract­Envelope.get­Lower­Corner()
• Abstract­Envelope.get­Minimum(int)

getUpper

public double getUpper(int dimension)
                throws IndexOutOfBoundsException

Returns the limit in the direction of increasing coordinate values in the specified dimension. This is usually the algebraic maximum, except if this envelope spans the anti-meridian.

Specified by:

get­Upper in class Abstract­Envelope

Parameters:

dimension - the dimension for which to obtain the coordinate value.

Returns:

the starting coordinate value at the given dimension.

Throws:

Index­Out­Of­Bounds­Exception - if the given index is negative or is equal or greater than the envelope dimension.

See Also:

• Abstract­Envelope.get­Upper­Corner()
• Abstract­Envelope.get­Maximum(int)

getMinimum

public double getMinimum(int dimension)
                  throws IndexOutOfBoundsException

Returns the minimal coordinate value for the specified dimension. In the typical case of non-empty envelopes not crossing the anti-meridian, this method returns the Abstract­Envelope.get­Lower(int) value verbatim. In the case of envelope crossing the anti-meridian, this method returns the axis minimum value. If the range in the given dimension is invalid, then this method returns Na­N.

Specified by:

get­Minimum in interface Envelope

Overrides:

get­Minimum in class Abstract­Envelope

Parameters:

dimension - the dimension for which to obtain the coordinate value.

Returns:

the minimal coordinate value at the given dimension.

Throws:

Index­Out­Of­Bounds­Exception - if the given index is negative or is equal or greater than the envelope dimension.

getMaximum

public double getMaximum(int dimension)
                  throws IndexOutOfBoundsException

Returns the maximal coordinate value for the specified dimension. In the typical case of non-empty envelopes not crossing the anti-meridian, this method returns the Abstract­Envelope.get­Upper(int) value verbatim. In the case of envelope crossing the anti-meridian, this method returns the axis maximum value. If the range in the given dimension is invalid, then this method returns Na­N.

Specified by:

get­Maximum in interface Envelope

Overrides:

get­Maximum in class Abstract­Envelope

Parameters:

dimension - the dimension for which to obtain the coordinate value.

Returns:

the maximal coordinate value at the given dimension.

Throws:

Index­Out­Of­Bounds­Exception - if the given index is negative or is equal or greater than the envelope dimension.

getMedian

public double getMedian(int dimension)
                 throws IndexOutOfBoundsException

Returns the median coordinate along the specified dimension. In most cases, the result is equal (minus rounding error) to:

median = (getUpper(dimension) + getLower(dimension)) / 2;

Crossing the anti-meridian of a Geographic CRS

If upper < lower and the range meaning for the requested dimension is wraparound, then the median calculated above is actually in the middle of the space outside the envelope. In such cases, this method shifts the median value by half of the periodicity (180° in the longitude case) in order to switch from outer space to inner space. If the axis range meaning is not WRAPAROUND, then this method returns Na­N.

Specified by:

get­Median in interface Envelope

Overrides:

get­Median in class Abstract­Envelope

Parameters:

dimension - the dimension for which to obtain the coordinate value.

Returns:

the median coordinate at the given dimension, or Double.Na­N.

Throws:

Index­Out­Of­Bounds­Exception - if the given index is negative or is equal or greater than the envelope dimension.

See Also:

• Abstract­Envelope.get­Median()

getSpan

public double getSpan(int dimension)
               throws IndexOutOfBoundsException

Returns the envelope span (typically width or height) along the specified dimension. In most cases, the result is equal (minus rounding error) to:

span = getUpper(dimension) - getLower(dimension);

Crossing the anti-meridian of a Geographic CRS

If upper < lower and the range meaning for the requested dimension is wraparound, then the span calculated above is negative. In such cases, this method adds the periodicity (typically 360° of longitude) to the span. If the result is a positive number, it is returned. Otherwise this method returns Na­N.

Specified by:

get­Span in interface Envelope

Overrides:

get­Span in class Abstract­Envelope

Parameters:

dimension - the dimension for which to obtain the span.

Returns:

the span (typically width or height) at the given dimension, or Double.Na­N.

Throws:

Index­Out­Of­Bounds­Exception - if the given index is negative or is equal or greater than the envelope dimension.

isEmpty

public boolean isEmpty()

Determines whether or not this envelope is empty. An envelope is empty if it has zero dimension, or if the span of at least one axis is negative, 0 or Na­N.

Note: Strictly speaking, there is an ambiguity if a span is Na­N or if the envelope contains both 0 and infinite spans (since 0⋅∞ = Na­N). In such cases, this method arbitrarily ignores the infinite values and returns true.

If is­Empty() returns false, then Abstract­Envelope.is­All­Na­N() is guaranteed to also return false. However, the converse is not always true.

Specified by:

is­Empty in interface Emptiable

Overrides:

is­Empty in class Abstract­Envelope

Returns:

true if this envelope is empty.

See Also:

• Default­Geographic­Bounding­Box.is­Empty()
• Rectangular­Shape.is­Empty()

isAllNaN

public boolean isAllNaN()

Returns false if at least one coordinate value is not NaN. This is­All­Na­N() check is different than the Abstract­Envelope.is­Empty() check since it returns false for a partially initialized envelope, while is­Empty() returns false only after all dimensions have been initialized. More specifically, the following rules apply:

• If is­All­Na­N() == true, then is­Empty() == true
• If is­Empty() == false, then is­All­Na­N() == false
• The converse of the above-cited rules are not always true.

Note that an all-NaN envelope can still have a non-null coordinate reference system.

Overrides:

is­All­Na­N in class Abstract­Envelope

Returns:

true if this envelope has NaN values.

See Also:

• set­To­Na­N()
• Default­Geographic­Bounding­Box.is­Empty()

hashCode

public int hashCode()

Returns a hash value for this envelope.

Overrides:

hash­Code in class Abstract­Envelope

equals

public boolean equals(Object object)

Returns true if the specified object is an envelope of the same class with equals coordinates and CRS.

Implementation note

This implementation requires that the provided object argument is of the same class than this envelope. We do not relax this rule since not every implementations in the SIS code base follow the same contract.

Overrides:

equals in class Abstract­Envelope

Parameters:

object - the object to compare with this envelope.

Returns:

true if the given object is equal to this envelope.

toString

public String toString()

Formats this envelope as a "BOX" element. The output is of the form "BOXnD(lower corner,upper corner)" where n is the number of dimensions. The number of dimension is written only if different than 2. Examples:

• BOX(-90 -180, 90 180)
• BOX3D(-90 -180 0, 90 180 1)

This method formats the numbers as with Double.to­String(double) (i.e. without fixed number of fraction digits). The string returned by this method can be parsed by the General­Envelope constructor.

Note on standards

The BOX element is not part of the standard Well Known Text (WKT) format. However, it is understood by many software libraries, for example GDAL and PostGIS.

Overrides:

to­String in class Abstract­Envelope

Returns:

this envelope as a BOX or BOX3D (most typical dimensions) element.