uk.ac.starlink.ast
Class Ellipse
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.Ellipse
public class Ellipse
- extends Region
Java interface to the AST Ellipse class
- an elliptical region within a 2-dimensional Frame.
The Ellipse class implements a Region which represents a ellipse
within a 2-dimensional Frame.
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 Ellipse
Constructor Summary |
Ellipse(Frame frame,
int form,
double[] centre,
double[] point1,
double[] point2,
Region unc)
Create a Ellipse. |
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 |
Ellipse
public Ellipse(Frame frame,
int form,
double[] centre,
double[] point1,
double[] point2,
Region unc)
- Create a Ellipse.
This function creates a new Ellipse and optionally initialises its
attributes.
A Ellipse is a Region which represents a elliptical area within the
supplied 2-dimensional Frame.
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.
- Parameters:
frame
- A pointer to the Frame in which the region is defined. It must
have exactly 2 axes. 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 ellipse is described by the remaining parameters.
A value of zero indicates that the ellipse is specified by a
centre position and two positions on the circumference. A value of
one indicates that the ellipse is specified by its centre position,
the half-lengths of its two axes, and the orientation of its first
axis.centre
- An array of 2 doubles,
containing the coordinates at the centre of
the ellipse.point1
- An array of 2 doubles. If "form"
is zero, this array should contain the coordinates of one of the four
points where an axis of the ellipse crosses the circumference of the
ellipse.
If "form"
is one, it should contain the lengths of semi-major and
semi-minor axes of the ellipse, given as geodesic distances
within the Frame.point2
- An array of 2 doubles. If "form"
is zero, this array should containing the coordinates at some other
point on the circumference of the ellipse, distinct from
"point1". If "form"
is one, the first element of this array should hold the angle
between the second axis of the Frame and the first ellipse axis
(i.e. the ellipse axis which is specified first in the
"point1"
array), and the second element will be ignored. The angle should be
given in radians, measured positive in the same sense as rotation
from the positive direction of the second Frame axis to the positive
direction of the first Frame axis.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 © 2019 Central Laboratory of the Research Councils. All Rights Reserved.