uk.ac.starlink.ast
Class Box
java.lang.Object
uk.ac.starlink.ast.AstObject
uk.ac.starlink.ast.Mapping
uk.ac.starlink.ast.Frame
uk.ac.starlink.ast.Region
uk.ac.starlink.ast.Box
public class Box
- extends Region
Java interface to the AST Box class
- a box region with sides parallel to the axes of a Frame.
The Box class implements a Region which represents a box with sides
parallel to the axes of a Frame (i.e. an area which encloses a given
range of values on each axis). A Box is similar to an Interval, the
only real difference being that the Interval class allows some axis
limits to be unspecified. Note, a Box will only look like a box if
the Frame geometry is approximately flat. For instance, a Box centred
close to a pole in a SkyFrame will look more like a fan than a box
(the Polygon class can be used to create a box-like region close to a
pole).
Licence
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public Licence as
published by the Free Software Foundation; either version 2 of
the Licence, or (at your option) any later version.
This program is distributed in the hope that it will be
useful,but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the GNU General Public Licence for more details.
You should have received a copy of the GNU General Public Licence
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street,Fifth Floor, Boston, MA
02110-1301, USA
- See Also:
- AST Box
Constructor Summary |
Box(Frame frame,
int form,
double[] point1,
double[] point2,
Region unc)
Create a Box. |
Methods inherited from class uk.ac.starlink.ast.Region |
getAdaptive, getBounded, getClosed, getFillFactor, getMeshSize, getNegated, getRegionBounds, getRegionFrame, getRegionPoints, getUnc, mapRegion, mask, maskB, maskD, maskF, maskI, maskL, maskS, negate, overlap, setAdaptive, setClosed, setFillFactor, setMeshSize, setNegated, setUnc, showMesh |
Methods inherited from class uk.ac.starlink.ast.Frame |
angle, axAngle, axDistance, axOffset, convert, distance, findFrame, format, getActiveUnit, getAlignSystem, getBottom, getDigits, getDigits, getDirection, getDomain, getDut1, getEpoch, getFormat, getLabel, getMatchEnd, getMaxAxes, getMinAxes, getNaxes, getNormUnit, getObsLat, getObsLon, getPermute, getPreserveAxes, getSymbol, getSystem, getTitle, getTop, getUnit, intersect, norm, offset, offset2, permAxes, pickAxes, resolve, setActiveUnit, setAlignSystem, setBottom, setDigits, setDigits, setDirection, setDomain, setDut1, setEpoch, setEpoch, setFormat, setLabel, setMatchEnd, setMaxAxes, setMinAxes, setObsLat, setObsLon, setPermute, setPreserveAxes, setSymbol, setSystem, setTitle, setTop, setUnit, unformat |
Methods inherited from class uk.ac.starlink.ast.Mapping |
decompose, getInvert, getNin, getNout, getReport, getTranForward, getTranInverse, invert, linearApprox, mapBox, mapSplit, rate, rebin, rebinD, rebinF, rebinI, resample, resampleB, resampleD, resampleF, resampleI, resampleL, resampleS, setInvert, setReport, simplify, tran1, tran2, tranGrid, tranN, tranP |
Methods inherited from class uk.ac.starlink.ast.AstObject |
annul, clear, copy, delete, equals, finalize, getAstConstantI, getB, getC, getD, getF, getI, getID, getIdent, getL, getNobject, getObjSize, getRefCount, hashCode, isThreaded, reportVersions, sameObject, set, setB, setC, setD, setF, setI, setID, setIdent, setL, show, test, tune |
Box
public Box(Frame frame,
int form,
double[] point1,
double[] point2,
Region unc)
- Create a Box.
This function creates a new Box and optionally initialises its
attributes.
The Box class implements a Region which represents a box with sides
parallel to the axes of a Frame (i.e. an area which encloses a given
range of values on each axis). A Box is similar to an Interval, the
only real difference being that the Interval class allows some axis
limits to be unspecified. Note, a Box will only look like a box if
the Frame geometry is approximately flat. For instance, a Box centred
close to a pole in a SkyFrame will look more like a fan than a box
(the Polygon class can be used to create a box-like region close to a
pole).
Notes
- A null Object pointer (AST__NULL) will be returned if this
function is invoked with the AST error status set, or if it
should fail for any reason.
Status Handling
The protected interface to this function includes an extra
parameter at the end of the parameter list descirbed above. This
parameter is a pointer to the integer inherited status
variable: "int *status".
- Parameters:
frame
- A pointer to the Frame in which the region is defined. A deep
copy is taken of the supplied Frame. This means that any
subsequent changes made to the Frame using the supplied pointer
will have no effect the Region.form
- Indicates how the box is described by the remaining parameters.
A value of zero indicates that the box is specified by a centre
position and a corner position. A value of one indicates that the
box is specified by a two opposite corner positions.point1
- An array of double, with one element for each Frame axis
(Naxes attribute). If
"form"
is zero, this array should contain the coordinates at the centre of
the box.
If "form"
is one, it should contain the coordinates at the corner of the box
which is diagonally opposite the corner specified by
"point2".point2
- An array of double, with one element for each Frame axis
(Naxes attribute) containing the coordinates at any corner of the
box.unc
- An optional pointer to an existing Region which specifies the
uncertainties associated with the boundary of the Box being created.
The uncertainty in any point on the boundary of the Box is found by
shifting the supplied "uncertainty" Region so that it is centred at
the boundary point being considered. The area covered by the
shifted uncertainty Region then represents the uncertainty in the
boundary position. The uncertainty is assumed to be the same for
all points.
If supplied, the uncertainty Region must be of a class for which
all instances are centro-symetric (e.g. Box, Circle, Ellipse, etc.)
or be a Prism containing centro-symetric component Regions. A deep
copy of the supplied Region will be taken, so subsequent changes to
the uncertainty Region using the supplied pointer will have no
effect on the created Box. Alternatively,
a NULL Object pointer
may be supplied, in which case a default uncertainty is used
equivalent to a box 1.0E-6 of the size of the Box being created.
The uncertainty Region has two uses: 1) when the
astOverlap
function compares two Regions for equality the uncertainty
Region is used to determine the tolerance on the comparison, and 2)
when a Region is mapped into a different coordinate system and
subsequently simplified (using
astSimplify),
the uncertainties are used to determine if the transformed boundary
can be accurately represented by a specific shape of Region.
- Throws:
AstException
- if an error occurred in the AST library
Copyright © 2015 Central Laboratory of the Research Councils. All Rights Reserved.