Class GridGeometry
 All Implemented Interfaces:
Serializable
,LenientComparable
GridGeometry
contains:
 A grid extent (a.k.a. grid envelope),
often inferred from the
RenderedImage
size.  A grid to CRS transform, which may be inferred from the grid extent and the georeferenced envelope.
 A georeferenced envelope, which can be inferred from the grid extent and the grid to CRS transform.
 An optional Coordinate Reference System (CRS) specified as part of the georeferenced envelope. This CRS is the target of the grid to CRS transform.
 An estimation of
grid resolution
along each CRS axes, computed from the grid to CRS transform and eventually from the grid extent.  An indication of whether conversion for some axes is linear or not.
GridGeometry
knows nothing about RenderedImage
,
but GridCoverage2D
has this information and may use it for providing a missing grid extent.
By default, any request for an undefined property will throw an IncompleteGridGeometryException
.
In order to check if a property is defined, use isDefined(int)
.
Nonlinear referencing
A key property is the "grid to CRS" conversion, which defines how to map pixel coordinates to "real world" coordinates such as latitudes and longitudes. This relationship is often linear (an affine transform), but not necessarily;GridGeometry
accepts nonlinear conversions as well. Nonlinear conversions may occur with images
using localization grids,
but nonlinear conversions should not be used for expressing map projections (projections should be specified
in the Coordinate Reference System (CRS) instead).
Some applications can not handle nonlinear "grid to CRS" conversions.
For example encoding an image in a GeoTIFF file is much simpler if the "grid to CRS" conversion is linear.
The DomainLinearizer
class can be used for replacing nonlinear conversions by linear approximations.
Multithreading
GridGeometry
instances are immutable and threadsafe.
The same instance can be shared by different GridCoverage
instances. Since:
 1.0
 See Also:
Defined in the sisfeature
module

Field Summary
Modifier and TypeFieldDescriptionstatic final int
A bitmask to specify the validity of the Coordinate Reference System property.protected final ImmutableEnvelope
The geodetic envelope, ornull
if unknown.static final int
A bitmask to specify the validity of the geodetic envelope property.protected final GridExtent
The valid domain of a grid coverage, ornull
if unknown.static final int
A bitmask to specify the validity of the grid extent property.static final int
A bitmask to specify the validity of the geographic bounding box.static final int
A bitmask to specify the validity of the "grid to CRS" transform.protected final MathTransform
The conversion from grid indices to "real world" coordinates, ornull
if unknown.protected final double[]
An estimation of the grid resolution, in units of the CRS axes.static final int
A bitmask to specify the validity of the grid resolution.static final int
A bitmask to specify the validity of the temporal period.static final GridGeometry
An "empty" grid geometry with no value defined. 
Constructor Summary
ModifierConstructorDescriptionGridGeometry
(GridExtent extent, Envelope envelope, GridOrientation orientation) Creates an axisaligned grid geometry with an extent and an envelope.GridGeometry
(GridExtent extent, PixelInCell anchor, MathTransform gridToCRS, CoordinateReferenceSystem crs) Creates a new grid geometry from a grid extent and a mapping from cell coordinates to "real world" coordinates.protected
GridGeometry
(GridGeometry other) Creates a new grid geometry with the same values than the given grid geometry.GridGeometry
(GridGeometry other, GridExtent extent, MathTransform toOther) Creates a new grid geometry derived from the given grid geometry with a new extent and a modified transform.GridGeometry
(PixelInCell anchor, MathTransform gridToCRS, Envelope envelope, GridRoundingMode rounding) Creates a new grid geometry from a geospatial envelope and a mapping from cell coordinates to "real world" coordinates. 
Method Summary
Modifier and TypeMethodDescriptioncreateTransformTo
(GridGeometry target, PixelInCell anchor) Creates a transform from cell coordinates in this grid to cell coordinates in the given grid.derive()
Returns an object that can be used for creating a new grid geometry derived from this grid geometry.boolean
Compares the specified object with this grid geometry for equality.boolean
equals
(Object object, ComparisonMode mode) Compares the specified object with this grid geometry for equality.Returns the "real world" coordinate reference system.final int
Returns the number of dimensions of the grid.Returns the bounding box of "real world" coordinates for this grid geometry.Returns the "real world" bounding box of this grid geometry transformed to the given CRS.Returns the valid coordinate range of a grid coverage.Returns the approximate latitude and longitude coordinates of the grid.getGridToCRS
(PixelInCell anchor) Returns the conversion from grid coordinates to "real world" coordinates.double[]
getResolution
(boolean allowEstimates) Returns an estimation of the grid resolution, in units of the coordinate reference system axes.Instant[]
Returns the start time and end time of coordinates of the grid.int
Returns a hash value for this grid geometry.boolean
isConversionLinear
(int... targets) Indicates whether the grid to CRS conversion is linear for all the specified CRS axes.boolean
isDefined
(int bitmask) Returnstrue
if all the properties specified by the argument are set.reduce
(int... dimensions) Returns a grid geometry that encompass only some dimensions of this grid geometry.Returns a string representation of this grid geometry.Returns a tree representation of some elements of this grid geometry.translate
(long... translation) Returns a grid geometry translated by the given amount of cells compared to this grid.

Field Details

CRS
public static final int CRSA bitmask to specify the validity of the Coordinate Reference System property. 
ENVELOPE
public static final int ENVELOPEA bitmask to specify the validity of the geodetic envelope property. 
EXTENT
public static final int EXTENTA bitmask to specify the validity of the grid extent property. See Also:

GRID_TO_CRS
public static final int GRID_TO_CRSA bitmask to specify the validity of the "grid to CRS" transform. 
RESOLUTION
public static final int RESOLUTIONA bitmask to specify the validity of the grid resolution. 
GEOGRAPHIC_EXTENT
public static final int GEOGRAPHIC_EXTENTA bitmask to specify the validity of the geographic bounding box. This information can sometime be derived from the envelope and the CRS. It is an optional element even with a complete grid geometry since the coordinate reference system is not required to have an horizontal component. See Also:

TEMPORAL_EXTENT
public static final int TEMPORAL_EXTENTA bitmask to specify the validity of the temporal period. This information can sometime be derived from the envelope and the CRS. It is an optional element even with a complete grid geometry since the coordinate reference system is not required to have a temporal component. See Also:

extent
The valid domain of a grid coverage, ornull
if unknown. The lowest valid grid coordinate is zero forBufferedImage
, but may be nonzero for arbitraryRenderedImage
. A grid with 512 cells can have a minimum coordinate of 0 and maximum of 511. See Also:

envelope
The geodetic envelope, ornull
if unknown. If nonnull, this envelope is usually the gridextent
transformed to real world coordinates. The Coordinate Reference System} (CRS) of this envelope defines the "real world" CRS of this grid geometry. See Also:

gridToCRS
The conversion from grid indices to "real world" coordinates, ornull
if unknown. If nonnull, the conversion shall map cell center. This conversion is usually, but not necessarily, affine. 
resolution
protected final double[] resolutionAn estimation of the grid resolution, in units of the CRS axes. Computed fromgridToCRS
, eventually together withextent
. May benull
if unknown. If nonnull, the array length is equals to the number of CRS dimensions. See Also:

UNDEFINED
An "empty" grid geometry with no value defined. All getter methods invoked on this instance will causeIncompleteGridGeometryException
to be thrown. This instance can be used as a placeholder when the grid geometry can not be obtained.


Constructor Details

GridGeometry
Creates a new grid geometry with the same values than the given grid geometry. This is a copy constructor for subclasses. Parameters:
other
 the other grid geometry to copy.

GridGeometry
public GridGeometry(GridGeometry other, GridExtent extent, MathTransform toOther) throws TransformException Creates a new grid geometry derived from the given grid geometry with a new extent and a modified transform. This constructor is used for creating a grid geometry over a subregion (for example with the grid extent computed byGridDerivation.subgrid(Envelope, double...)
) or grid geometry for a subsampled raster.Conversion between old and new grid geometry
IftoOther
is nonnull, it defines the conversion from grid coordinates of givenextent
to grid coordinates ofother
. That transform should be a scale and a translation only, but more complex transforms are accepted. ThecornerToCRS
transform of the new grid geometry will be set to the following concatenation:
The new grid geometry envelope will be computed from the new extent and transform, then clipped to the envelope of the other grid geometry. This clip is for preventing the envelope to become larger under the effect of subsampling because each cell become larger. The clip is not applied whenthis.cornerToCRS
=toOther
→other.cornerToCRS
toOther
isnull
because in such case, we presume that the grid extent has been changed for another reason than subsampling (e.g. application of a margin, in which case we want the envelope to be expanded). Parameters:
other
 the other grid geometry to copy.extent
 the new extent for the grid geometry to construct, ornull
if none.toOther
 transform from this grid coordinates toother
grid coordinates, ornull
if none. Throws:
NullPointerException
 ifextent
isnull
and the other grid geometry contains no other information.TransformException
 if the math transform can not compute the geospatial envelope from the grid extent. Since:
 1.2
 See Also:

GridGeometry
public GridGeometry(GridExtent extent, PixelInCell anchor, MathTransform gridToCRS, CoordinateReferenceSystem crs) Creates a new grid geometry from a grid extent and a mapping from cell coordinates to "real world" coordinates. At least one ofextent
,gridToCRS
orcrs
arguments shall be nonnull. IfgridToCRS
is nonnull, thenanchor
shall be nonnull too with one of the following values:PixelInCell.CELL_CENTER
if conversions of cell indices bygridToCRS
give "real world" coordinates close to the center of each cell.PixelInCell.CELL_CORNER
if conversions of cell indices bygridToCRS
give "real world" coordinates at the corner of each cell. The cell corner is the one for which all grid indices have the smallest values (closest to negative infinity).
API note: there is no default value foranchor
because experience shows that images shifted by ½ pixel (with pixels that may be tens of kilometres large) is a recurrent problem. We want to encourage developers to always think about wether their grid to CRS transform is mapping pixel corner or center.Upcoming API generalization: theextent
type of this method may be changed toGridEnvelope
interface in a future Apache SIS version. This is pending GeoAPI update. In addition, thePixelInCell
code list currently defined in theorg.opengis.referencing.datum
package may move in another package in a future GeoAPI version because this type is no longer defined by the ISO 19111 standard after the 2018 revision. Parameters:
extent
 the valid extent of grid coordinates, ornull
if unknown.anchor
 Cell center for OGC conventions or cell corner for Java2D/JAI conventions.gridToCRS
 the mapping from grid coordinates to "real world" coordinates, ornull
if unknown.crs
 the coordinate reference system of the "real world" coordinates, ornull
if unknown. Throws:
NullPointerException
 ifextent
,gridToCRS
andcrs
arguments are all null.MismatchedDimensionException
 if the math transform and the CRS do not have consistent dimensions.IllegalGridGeometryException
 if the math transform can not compute the geospatial envelope or resolution from the grid extent.

GridGeometry
public GridGeometry(PixelInCell anchor, MathTransform gridToCRS, Envelope envelope, GridRoundingMode rounding) Creates a new grid geometry from a geospatial envelope and a mapping from cell coordinates to "real world" coordinates. At least one ofgridToCRS
orenvelope
arguments shall be nonnull. IfgridToCRS
is nonnull, thenanchor
shall be nonnull too with one of the values documented in theconstructor expecting a grid extent
.The given envelope shall encompass all cell surfaces, from the left border of leftmost cell to the right border of the rightmost cell and similarly along other axes. This constructor tries to store a geospatial envelope close to the specified envelope, but there is no guarantee that the envelope returned by
getEnvelope()
will be equal to the given envelope. The envelope stored in the newGridGeometry
may be slightly smaller, larger or shifted because the floating point values used in geospatial envelope can not always be mapped to the integer coordinates used inGridExtent
. The rules for deciding whether coordinates should be rounded toward nearest integers, to floor or to ceil values are specified by theGridRoundingMode
argument.Because of the uncertainties explained in above paragraph, this constructor should be used only in last resort, when the grid extent is unknown. For determinist results, developers should prefer the constructor using grid extent as much as possible. In particular, this constructor is not suitable for computing grid geometry of tiles in a tiled image, because the abovecited uncertainties may result in apparently random black lines between tiles.
Upcoming API change: ThePixelInCell
code list currently defined in theorg.opengis.referencing.datum
package may move in another package in a future GeoAPI version because this type is no longer defined by the ISO 19111 standard after the 2018 revision. This code list may be taken by ISO 19123 in a future revision. Parameters:
anchor
 Cell center for OGC conventions or cell corner for Java2D/JAI conventions.gridToCRS
 the mapping from grid coordinates to "real world" coordinates, ornull
if unknown.envelope
 the geospatial envelope, including its coordinate reference system if available. There is no guarantee that the envelope actually stored in theGridGeometry
will be equal to this specified envelope.rounding
 controls behavior of rounding from floating point values to integers. Throws:
IllegalGridGeometryException
 if the math transform can not compute the grid extent or the resolution.

GridGeometry
Creates an axisaligned grid geometry with an extent and an envelope. This constructor can be used when the grid to CRS transform is unknown. If only the coordinate reference system is known, then the envelope coordinates can be all NaN.The main purpose of this constructor is to create "desired" grid geometries, for example for use in read or resample operations. For grid geometries describing preexisting data, it is safer and more flexible to use one of the constructors expecting a
MathTransform
argument.Dimension order
The given envelope shall always declare dimensions in same order than the given extent. This constructor may reorder axes iforientation
is (for example)GridOrientation.DISPLAY
, but in such case this constructor will derive itself an envelope and a CRS with reordered axes. Parameters:
extent
 the valid extent of grid coordinates, ornull
if unknown.envelope
 the envelope together with CRS of the "real world" coordinates, ornull
if unknown.orientation
 highlevel description of desired characteristics of thegridToCRS
transform. Ignored (can be null) ifenvelope
is null. Throws:
NullPointerException
 ifextent
andenvelope
arguments are both null, or ifenvelope
is nonnull butorientation
is null. Since:
 1.1
 See Also:


Method Details

getDimension
public final int getDimension()Returns the number of dimensions of the grid. This is typically the same than the number of envelope dimensions or the number of coordinate reference system dimensions, but not necessarily. Returns:
 the number of grid dimensions.
 See Also:

getExtent
Returns the valid coordinate range of a grid coverage. The lowest valid grid coordinate is zero forBufferedImage
, but may be nonzero for arbitraryRenderedImage
. A grid with 512 cells can have a minimum coordinate of 0 and maximum of 511.Upcoming API generalization: the return type of this method may be changed toGridEnvelope
interface in a future Apache SIS version. This is pending GeoAPI update. Returns:
 the valid extent of grid coordinates (never
null
).  Throws:
IncompleteGridGeometryException
 if this grid geometry has no extent — i.e.isDefined(EXTENT)
returnedfalse
.

getGridToCRS
Returns the conversion from grid coordinates to "real world" coordinates. The conversion is often an affine transform, but not necessarily. Conversions from cell indices to geospatial coordinates can be performed for example as below:
Callers must specify whether they want the "real world" coordinates of cell center or cell corner. The cell corner is the one for which all grid indices have the smallest values (closest to negative infinity). As a rule of thumb:MathTransform gridToCRS = gridGeometry.getGridToCRS(PixelInCell.CELL_CENTER); DirectPosition indicesOfCell = new GeneralDirectPosition(2, 3, 4): DirectPosition aPixelCenter = gridToCRS.transform(indicesOfCell, null);
 Use
PixelInCell.CELL_CENTER
for transforming points.  Use
PixelInCell.CELL_CORNER
for transforming envelopes with inclusive lower coordinates and exclusive upper coordinates.
API note: there is no default value foranchor
because experience shows that images shifted by ½ pixel (with pixels that may be tens of kilometres large) is a recurrent problem. We want to encourage developers to always think about wether the desired grid to CRS transform shall map pixel corner or center. Parameters:
anchor
 the cell part to map (center or corner). Returns:
 the conversion from grid coordinates to "real world" coordinates (never
null
).  Throws:
IllegalArgumentException
 if the givenanchor
is not a known code list value.IncompleteGridGeometryException
 if this grid geometry has no transform — i.e.isDefined(GRID_TO_CRS)
returnedfalse
.
 Use

getCoordinateReferenceSystem
Returns the "real world" coordinate reference system. Returns:
 the coordinate reference system (never
null
).  Throws:
IncompleteGridGeometryException
 if this grid geometry has no CRS — i.e.isDefined(CRS)
returnedfalse
.

getEnvelope
Returns the bounding box of "real world" coordinates for this grid geometry. This envelope is computed from the grid extent, which is transformed to the "real world" coordinate system. The initial envelope encompasses all cell surfaces, from the left border of leftmost cell to the right border of the rightmost cell and similarly along other axes. If this grid geometry is a subgrid, then the envelope is also clipped to the envelope of the original (non subsampled) grid geometry. Returns:
 the bounding box in "real world" coordinates (never
null
).  Throws:
IncompleteGridGeometryException
 if this grid geometry has no envelope — i.e.isDefined(ENVELOPE)
returnedfalse
.

getEnvelope
Returns the "real world" bounding box of this grid geometry transformed to the given CRS. This envelope is computed from the grid extent if available, or from the envelope otherwise. Parameters:
crs
 the desired coordinate reference system for the returned envelope. Returns:
 the bounding box in "real world" coordinates (never
null
).  Throws:
IncompleteGridGeometryException
 if this grid geometry has no extent and no envelope.TransformException
 if the envelope can not be transformed to the specified CRS. Since:
 1.2

getGeographicExtent
Returns the approximate latitude and longitude coordinates of the grid. The prime meridian is Greenwich, but the geodetic reference frame is not necessarily WGS 84. This is computed from the envelope if the coordinate reference system contains an horizontal component such as a geographic or projected CRS.API note: this method does not throwIncompleteGridGeometryException
because the geographic extent may be absent even with a complete grid geometry. Grid geometries are not required to have a spatial component on Earth surface; a raster could be a vertical profile for example. Returns:
 the geographic bounding box in "real world" coordinates.

getTemporalExtent
Returns the start time and end time of coordinates of the grid. If the grid has no temporal dimension, then this method returns an empty array. If only the start time or end time is defined, then returns an array of length 1. Otherwise this method returns an array of length 2 with the start time in the first element and the end time in the last element. Returns:
 time range as an array of length 0 (if none), 1 or 2.

getResolution
public double[] getResolution(boolean allowEstimates) Returns an estimation of the grid resolution, in units of the coordinate reference system axes. The length of the returned array is the number of CRS dimensions, withresolution[0]
being the resolution along the first CRS axis,resolution[1]
the resolution along the second CRS axis, etc. Note that this axis order is not necessarily the same than grid axis order.If the resolution at CRS dimension i is not a constant factor (i.e. the
isConversionLinear(i)
returnsfalse
), thenresolution[i]
is set to one of the following values:Double.NaN
ifallowEstimates
isfalse
. An arbitrary representative resolution otherwise.
Current implementation computes the resolution at
grid center
, but different implementations may use alternative algorithms.
 Parameters:
allowEstimates
 whether to provide some values even for resolutions that are not constant factors. Returns:
 an estimation of the grid resolution (never
null
).  Throws:
IncompleteGridGeometryException
 if this grid geometry has no resolution — i.e.isDefined(RESOLUTION)
returnedfalse
.

isConversionLinear
public boolean isConversionLinear(int... targets) Indicates whether the grid to CRS conversion is linear for all the specified CRS axes. The conversion from grid coordinates to real world coordinates is often linear for some dimensions, typically the horizontal ones at indices 0 and 1. But the vertical dimension (usually at index 2) is often nonlinear, for example with data at 0, 5, 10, 100 and 1000 metres. Parameters:
targets
 indices of CRS axes. This is not necessarily the same than indices of grid axes. Returns:
true
if the conversion from grid coordinates to "real world" coordinates is linear for all the given CRS dimension.

isDefined
public boolean isDefined(int bitmask) Returnstrue
if all the properties specified by the argument are set. If this method returnstrue
, then invoking the corresponding getter methods will not throwIncompleteGridGeometryException
. Parameters:
bitmask
 any combination ofCRS
,ENVELOPE
,EXTENT
,GRID_TO_CRS
andRESOLUTION
. Returns:
true
if all specified properties are defined (i.e. invoking the corresponding getter methods will not throwIncompleteGridGeometryException
). Throws:
IllegalArgumentException
 if the specified bitmask is not a combination of known masks. See Also:

derive
Returns an object that can be used for creating a new grid geometry derived from this grid geometry.GridDerivation
does not change the state of thisGridGeometry
but instead creates new instances as needed. Examples of modifications include clipping to a subarea or applying a subsampling.Example: for clipping this grid geometry to a subarea, one can use:EachGridGeometry gg = ...; Envelope areaOfInterest = ...; gg = gg.derive().rounding(GridRoundingMode.ENCLOSING) .subgrid(areaOfInterest).build();
GridDerivation
instance can be used only once and should be used in a single thread.GridDerivation
preserves the number of dimensions. For example slicing sets the grid size to 1 in all dimensions specified by a slice point, but does not remove those dimensions from the grid geometry. For dimensionality reduction, seereduce(int...)
. Returns:
 an object for deriving a grid geometry from
this
.

translate
Returns a grid geometry translated by the given amount of cells compared to this grid. The returned grid has the same size than this grid, i.e. both low and high grid coordinates are displaced by the same amount of cells. The "grid to CRS" transforms are adjusted accordingly in order to map to the same "real world" coordinates.Number of arguments
Thetranslation
array length should be equal to the number of dimensions. If the array is shorter, missing values default to 0 (i.e. no translation in unspecified dimensions). If the array is longer, extraneous values are ignored. Parameters:
translation
 translation to apply on each grid axis in order. Returns:
 a grid geometry whose coordinates (both low and high ones) and the "grid to CRS" transforms have been translated by given amounts. If the given translation is a noop (no value or only 0 ones), then this grid is returned as is.
 Throws:
ArithmeticException
 if the translation results in coordinates that overflow 64bits integer. Since:
 1.1
 See Also:

reduce
Returns a grid geometry that encompass only some dimensions of this grid geometry. The specified dimensions will be copied into a new grid geometry if necessary. The selection is applied on grid extent dimensions; they are not necessarily the same than the envelope dimensions. The given dimensions must be in strictly ascending order without duplicated values. The number of dimensions of the sub grid geometry will bedimensions.length
.This method performs a dimensionality reduction. This method can not be used for changing dimension order.
 Parameters:
dimensions
 the grid (not CRS) dimensions to select, in strictly increasing order. Returns:
 the subgrid geometry, or
this
if the given array contains all dimensions of this grid geometry.  Throws:
IndexOutOfBoundsException
 if an index is out of bounds. See Also:

createTransformTo
public MathTransform createTransformTo(GridGeometry target, PixelInCell anchor) throws TransformException Creates a transform from cell coordinates in this grid to cell coordinates in the given grid. The returned transform handles change of Coordinate Reference System and wraparound axes (e.g. longitude axis crossing the ±180° meridian) if applicable.Note: the transform created by this method may be noninvertible.
 Parameters:
target
 the grid which will be the target of returned transform.anchor
 Cell center for OGC conventions or cell corner for Java2D/JAI conventions. Returns:
 transform from cell coordinates in this grid to cell coordinates in the given grid.
 Throws:
TransformException
 if the math transform can not be created. Since:
 1.1

hashCode
public int hashCode()Returns a hash value for this grid geometry. This value needs not to remain consistent between different implementations of the same class. 
equals
Compares the specified object with this grid geometry for equality. This method delegates toequals(object, ComparisonMode.STRICT)
. Specified by:
equals
in interfaceLenientComparable
 Overrides:
equals
in classObject
 Parameters:
object
 the object to compare with. Returns:
true
if the given object is equals to this grid geometry. See Also:

equals
Compares the specified object with this grid geometry for equality. If the mode isComparisonMode.IGNORE_METADATA
or more flexible, then the axis types are ignored. Specified by:
equals
in interfaceLenientComparable
 Parameters:
object
 the object to compare with this grid geometry for equality.mode
 the strictness level of the comparison. Returns:
true
if the given object is equal to this grid geometry. Since:
 1.1
 See Also:

toString
Returns a string representation of this grid geometry. The returned string is implementation dependent and may change in any future version. Current implementation is equivalent to a call totoTree(Locale, int)
with at leastEXTENT
,ENVELOPE
andCRS
flags. Whether more flags are present or not is unspecified. 
toTree
Returns a tree representation of some elements of this grid geometry. The tree representation is for debugging or logging purposes and may change in any future SIS version. Parameters:
locale
 the locale to use for textual labels.bitmask
 combination ofEXTENT
,ENVELOPE
,CRS
,GRID_TO_CRS
,RESOLUTION
,GEOGRAPHIC_EXTENT
andTEMPORAL_EXTENT
. Returns:
 a tree representation of the specified elements.
