Extent or Metadata objects.
This class provides methods for:
- Fetching geographic, vertical or temporal components in a convenient form.
- Computing intersection of bounding boxes
- Computing area estimations.
- Since:
- 0.3
- See Also:
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Field Summary
Fields -
Method Summary
Modifier and TypeMethodDescriptionstatic doubleReturns an estimation of the area (in square metres) of the given bounding box.static DirectPositionReturns the position at the median longitude and latitude values of the given bounding box.static Collection<? extends Extent> fromIdentificationInfo(Metadata metadata) Returns the extents found in allIdentificationelements of the given metadata.static DateReturns an instant in the temporal elements of the given extent, ornullif none.static StringgetDescription(Extent extent, Locale locale) Returns the description of the given extent, ornullif none.static Optional<GeographicBoundingBox> getGeographicBoundingBox(Stream<? extends Extent> extents) Returns a single geographic bounding box for the given extents.static GeographicBoundingBoxgetGeographicBoundingBox(Extent extent) Returns a single geographic bounding box from the specified extent.static GeographicBoundingBoxgetGeographicBoundingBox(Metadata metadata) Returns a single geographic bounding box from the specified metadata.getTimeRange(Extent extent) Returns the union of all time ranges found in the given extent, ornullif none.static MeasurementRange<Double> getVerticalRange(Extent extent) Returns the union of chosen vertical ranges found in the given extent, ornullif none.static Extentintersection(Extent e1, Extent e2) Returns the intersection of the given extents.static GeographicBoundingBoxReturns the intersection of the given geographic bounding boxes.static TemporalExtentReturns the intersection of the given temporal extents.static VerticalExtentReturns the intersection of the given vertical extents.static GeographicBoundingBoxReturns the union of the given geographic bounding boxes.
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Field Details
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WORLD
A geographic extent ranging from 180°W to 180°E and 90°S to 90°N. This extent has no vertical and no temporal components.
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Method Details
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fromIdentificationInfo
Returns the extents found in allIdentificationelements of the given metadata. If there is only oneIdentificationelement (which is the usual case), then its collection of extents is returned as-is; the collection is not copied.In the less usual case where there is many
Identificationelements providing non-empty collection of extents, then this method returns the union of all collections without duplicated elements (duplication determined byObject.equals(Object)). In the special case where the first non-empty collection of extents contains all other collections, then that collection is returned as-is.Rational: above policy makes a best effort for avoiding to create new collections. The reason is that collection implementations may perform lazy calculations ofExtentelements. This method tries to preserve the lazy behavior (if any).- Parameters:
metadata- the metadata, ornullif none.- Returns:
- extents found in all
Identificationelements, or an empty collection if none. - Since:
- 1.3
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getGeographicBoundingBox
Returns a single geographic bounding box from the specified metadata. If the given metadata contains manyIdentificationor manyExtentinstances, then this method returns the union of all of them.Use case
This convenience method is useful when the metadata is expected to contain only one bounding box, typically because the metadata were obtained from a resource which is known to support only singletons (one raster or one set of features). For more general cases, it is often more appropriate to handle each bounding box separately usinggetGeographicBoundingBox(Extent).- Parameters:
metadata- the metadata from which to get a global bounding box, ornullif none.- Returns:
- a global bounding box for all extents found in the given metadata, or
nullif none. - Since:
- 1.1
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getGeographicBoundingBox
public static Optional<GeographicBoundingBox> getGeographicBoundingBox(Stream<? extends Extent> extents) Returns a single geographic bounding box for the given extents. For each extent, the bounding box is fetched withgetGeographicBoundingBox(Extent). If more than one geographic bound is found, this method computes their union.This is a convenience method for fetching the domain of validity of
Datum,CoordinateReferenceSystemorCoordinateOperationobjects.- Parameters:
extents- the extents for which to get a single geographic bounding box.- Returns:
- the union of all geographic bounding boxes found in all extents.
- Throws:
InvalidMetadataException- if an envelope cannot be transformed to a geographic bounding box.- Since:
- 1.4
- See Also:
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getGeographicBoundingBox
Returns a single geographic bounding box from the specified extent. This method tries to find the bounding box in the cheapest way before to fallback on more expensive computations:- First, this method searches geographic elements that are instance of
GeographicBoundingBox.- If exactly one such instance is found, then this method returns that instance directly (no copy).
- If more than one instance is found, then this method computes and returns the union of all bounding boxes.
- If above step found no
GeographicBoundingBox, then this method inspects geographic elements that are instance ofBoundingPolygon, taking in account only the envelopes associated to a coordinate reference system of kindGeographicCRS. If such envelopes are found, then this method computes and returns their union. - If above step found no polygon's envelope associated to a geographic CRS, then in last resort this method uses all polygon's envelopes regardless their coordinate reference system (provided that the CRS is not null), applying coordinate transformations if needed.
- If above step found no polygon's envelope, then this method returns
null.
- Parameters:
extent- the extent to convert to a geographic bounding box, ornull.- Returns:
- a geographic bounding box extracted from the given extent, or
nullif none. - Throws:
InvalidMetadataException- if an envelope cannot be transformed to a geographic bounding box.- See Also:
- First, this method searches geographic elements that are instance of
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getVerticalRange
Returns the union of chosen vertical ranges found in the given extent, ornullif none. This method gives preference to heights above the Mean Sea Level when possible. Depths have negative height values: if the axis direction is toward down, then this method reverses the sign of minimum and maximum values.Multi-occurrences
If the givenExtentobject contains more than one vertical extent, then this method performs a choice based on the vertical datum and the unit of measurement:Choice based on vertical datum
Only the extents associated (indirectly, through their CRS) to the same non-nullVerticalDatumTypewill be taken in account. If all datum types are null, then this method conservatively uses only the first vertical extent. Otherwise the datum type used for filtering the vertical extents is:VerticalDatumType.GEOIDALorDEPTHif at least one extent uses those datum types. For this method,DEPTHis considered as equivalent toGEOIDALexcept for the axis direction.- Otherwise, the first non-null datum type found in iteration order.
Rational: like geographic bounding box, the vertical range is an approximated information; the range returned by this method does not carry any information about the vertical CRS and this method does not attempt to perform coordinate transformation. But this method is more useful if the returned ranges are close to a frequently used surface, like the Mean Sea Level. The same simplification is applied in theVerticalExtentelement of Well Known Text (WKT) format, which specifies that “Vertical extent is an approximate description of location; heights are relative to an unspecified mean sea level.”Choice based on units of measurement
If, after the choice based on the vertical datum described above, there is still more than one vertical extent to consider, then the next criterion checks for the units of measurement.- If no range specify a unit of measurement, return the first range and ignore all others.
- Otherwise take the first range having a unit of measurement. Then:
- All other ranges having an incompatible unit of measurement will be ignored.
- All other ranges having a compatible unit of measurement will be converted to the unit of the first retained range, and their union will be computed.
Example: Heights or depths are often measured using some pressure units, for example hectopascals (hPa). AnExtentcould contain two vertical elements: one with the height measurements in hPa, and the other element with heights transformed to metres using an empirical formula. In such case this method will select the first vertical element on the assumption that it is the "main" one that the metadata producer intended to show. Next, this method will search for other vertical elements using pressure unit. In our example there is none, but if such elements were found, this method would compute their union.
- Parameters:
extent- the extent to convert to a vertical measurement range, ornull.- Returns:
- a vertical measurement range created from the given extent, or
nullif none. - Since:
- 0.4
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getTimeRange
Returns the union of all time ranges found in the given extent, ornullif none.- Parameters:
extent- the extent to convert to a time range, ornull.- Returns:
- a time range created from the given extent, or
nullif none. - Since:
- 0.4
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getDate
Returns an instant in the temporal elements of the given extent, ornullif none. First, this method computes the union of all temporal elements. Then this method computes the linear interpolation between the start and end time as in the following pseudo-code:Special cases:return new Date(startTime + (endTime - startTime) * location);- If
locationis 0, then this method returns the start time. - If
locationis 1, then this method returns the end time. - If
locationis 0.5, then this method returns the average of start time and end time. - If
locationis outside the [0 … 1] range, then the result will be outside the temporal extent.
- Parameters:
extent- the extent from which to get an instant, ornull.location- 0 for the start time, 1 for the end time, 0.5 for the average time, or the coefficient (usually in the [0 … 1] range) for interpolating an instant.- Returns:
- an instant interpolated at the given location, or
nullif none. - Since:
- 0.4
- If
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getDescription
Returns the description of the given extent, ornullif none.- Parameters:
extent- the extent from which to get a description, ornull.locale- desired locale, ornullfor default.- Returns:
- description of the given extent, or
nullif none. - Since:
- 1.1
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centroid
Returns the position at the median longitude and latitude values of the given bounding box. This method does not check the inclusion status. This method takes in account bounding boxes that cross the anti-meridian.- Parameters:
bbox- the bounding box for which to get the median longitude and latitude values, ornull.- Returns:
- a median position of the given bounding box, or
nullif none.
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area
Returns an estimation of the area (in square metres) of the given bounding box. SinceGeographicBoundingBoxprovides only approximated information (for example it does not specify the datum), the value returned by this method is also approximated.The current implementation performs its computation on the GRS 1980 Authalic Sphere. However, this may change in any future SIS version.
- Parameters:
box- the geographic bounding box for which to compute the area, ornull.- Returns:
- an estimation of the area in the given bounding box (m²), or NaN if the given box was null.
- Since:
- 0.4
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union
Returns the union of the given geographic bounding boxes. If any of the arguments isnull, then this method returns the other argument (which may be null). Otherwise this method returns a box which is the union of the two given boxes.This method never modify the given boxes, but may return directly one of the given arguments if it already represents the union result.
- Parameters:
b1- the first bounding box, ornull.b2- the second bounding box, ornull.- Returns:
- the union (may be any of the
b1orb2argument if unchanged), ornullif the two given boxes are null. - Since:
- 1.2
- See Also:
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intersection
public static GeographicBoundingBox intersection(GeographicBoundingBox b1, GeographicBoundingBox b2) Returns the intersection of the given geographic bounding boxes. If any of the arguments isnull, then this method returns the other argument (which may be null). Otherwise this method returns a box which is the intersection of the two given boxes. If there is no intersection, the returned bounding box containsDouble.NaNbounds.This method never modify the given boxes, but may return directly one of the given arguments if it already represents the intersection result.
- Parameters:
b1- the first bounding box, ornull.b2- the second bounding box, ornull.- Returns:
- the intersection (may be any of the
b1orb2argument if unchanged), ornullif the two given boxes are null. May containDouble.NaNbounds. - Throws:
IllegalArgumentException- if the inclusion status is not the same for both boxes.- Since:
- 0.4
- See Also:
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intersection
Returns the intersection of the given vertical extents. If any of the arguments isnull, then this method returns the other argument (which may be null). Otherwise this method returns a vertical extent which is the intersection of the two given extents.This method never modify the given extents, but may return directly one of the given arguments if it already represents the intersection result.
Advantage and inconvenient of this method
This method cannot intersect extents defined with different datums because height transformations generally require the geodetic positions (latitudes and longitudes) of the heights to transform. For more general transformations, it is better to convert all extent components into a single envelope, then transform the envelope at once. On the other hand, thisintersect(…)method preserves better theNilReason(if any).- Parameters:
e1- the first extent, ornull.e2- the second extent, ornull.- Returns:
- the intersection (may be any of the
e1ore2argument if unchanged), ornullif the two given extents are null. - Throws:
IllegalArgumentException- if the two extents do not use the same datum, ignoring metadata.- Since:
- 0.8
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intersection
Returns the intersection of the given temporal extents. If any of the arguments isnull, then this method returns the other argument (which may be null). Otherwise this method returns a temporal extent which is the intersection of the two given extents.This method never modify the given extents, but may return directly one of the given arguments if it already represents the intersection result.
- Parameters:
e1- the first extent, ornull.e2- the second extent, ornull.- Returns:
- the intersection (may be any of the
e1ore2argument if unchanged), ornullif the two given extents are null. - Throws:
UnsupportedOperationException- if no implementation ofTemporalFactoryhas been found on the module path.- Since:
- 0.8
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intersection
Returns the intersection of the given extents. If any of the arguments isnull, then this method returns the other argument (which may be null). Otherwise this method returns an extent which is the intersection of all geographic, vertical and temporal elements in the two given extents.This method never modify the given extents, but may return directly one of the given arguments if it already represents the intersection result.
- Parameters:
e1- the first extent, ornull.e2- the second extent, ornull.- Returns:
- the intersection (may be any of the
e1ore2argument if unchanged), ornullif the two given extents are null. - Throws:
IllegalArgumentException- if two elements to intersect are not compatible (e.g. mismatched bounding box inclusion status or mismatched vertical datum).UnsupportedOperationException- if aTemporalFactoryis required but no implementation has been found on the module path.- Since:
- 0.8
- See Also:
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