G History
This section describes the major changes introduced at each release of POLPACK.
G.1 V3.6-2
- The POLVEC and POLBIN commands have a new parameter called DEBIASTYPE that
can be used to select the de-biasing estimator to use. The traditional “asymptotic”
estimator is still available (option “AS”), but a “modified asymptotic” estimator (option
“MAS”) is now available that avoids the generation of PI values that are bad or identically
equal to zero.
G.2 V3.6-1
- Catalogues created by POLVEC now include valid I, Q, U and PI values for rows that
have negative total intensity. The P and ANG values remain bad for such rows.
G.3 V3.6-0
- A new command called POLSELECT has been added. This command allows rows to be
selected from a vector catalogue in threee different ways: 1) using a pixel maks defined
in an NDF, 2) using a region description (either ARD or AST), or 3) Using an algebraic
expression (like the CATSELECT command in CURSA).
G.4 V3.5-0
- The POLWRTCL command now excludes any rows that contain one or more bad values.
This means that literal bad values (-0.340282E+39) are no longer passed onto the GAIA
polarimetry toolbox.
- A new command called POLWCSCOPY has been added that copies WCS information
form one catalogue to another. It is useful for adding WCS information back into
catalogues that have had the WCS information stripped out - for instance by being
processed using TOPCAT or STILTS.
G.5 V3.4-0
- The ANGLE parameter of the POLROTREF command has been removed. A new
parameter called AXIS has been added, which allows the new reference direction to be
specified. Any existing scripts that use ANGLE will need to be changed - maybe by
using KAPPA:WCSADD to define a new coordinate frame in which one of the axes is
to be used as the reference direction.
G.6 V3.3-0
- POLKA no longer supports an unconstrained full 6-coefficient linear fit.
- A bug has been fixed in POLKA that could cause dialog boxes to flash uncontrollably
when partially obscured by the main polka window.
G.7 V3.2-0
- A new command called POLROTREF has been added which will rotate the reference
direction used by a pair of Q and U images.
- The POLVEC command now omits vectors from positions that have negative total
intensity values.
G.8 V3.1-5
- A bug in POLIMAGE that caused an error to be reported when deleting an AXIS Frame
from the NDF WCS FrameSet has been fixed.
- POLVEC now uses the absloute value of I to normalise the other STokes vectors.
Previously, a negative value of I would cause the normalised Q and U values to change
sign, resulting in the vector rotating by 90 degrees.
G.9 V3.1-3
- Error messages indicating that a required column is not available have been expanded to
suggest that deleting your $HOME/.polpackrc file may solve the problem. This file can be
left in a corrupt condition if a command fails whilst using the GAIA polarimetry toolbox.
G.10 V3.1
- POLPACK is now linked with native PGPLOT, instead of the Starlink GKS-based version
of PGPLOT.
- The hidden command DATAPIC (used within POLKA) has been removed.
G.11 V3.0
- Most POLPACK commands have been changed to allow the processing of
spectropolarimery data. The main exception to this is the POLKA command, which
cannot be used with spectropolarimetry data. Instead, you should align the data
manually, and then use POLCAL directly to create Stokes vectors.
- Bugs have been fixed which allow catalogues in STL and TST formats to be used (see
SUN/190).
- A bug in POLPLOT has been fixed which caused inappropriate text to be used for the
default key heading.
- A new hidden command POLZCONV has been added to transform between calibrated
values and pixel values along any spectral channel axis present in a vector catalogue. This
command is not intended for interactive use.
- Two new hidden commands POLWRTCL and POLRDCL have been added to transfer
catalogue data to and from the polarimetry toolbox within GAIA (SUN/214). These
commands are not designed for interactive use.
- POLIMP has a new parameter called ABORT which can be set TRUE to force POLIMP to
abort if any input data file cannot be processed.
G.12 V2.1-7
- A new logical-valued parameter called INTEGRATE has been added to POLBIN. If set
to a true value, the output catalogue contains only a single vector formed by binning all
vectors within the input catalogue. Otherwise, the output catalogue contains vectors for
a grid of bins determined by the BOX parameter, as before.
- Two new hidden commands POLWRTCL and POLRDTCL have been added to transfer
catalogue data to and from the polarimetry toolbox within GAIA (SUN/214). These
commands are not designed for interactive use.
G.13 V2.1-5
- The way POLBIN chooses the location of its bins has been changed. The bins are now
chosen so that origin of the (X,Y) co-ordinate system (as defined by the X and Y columns
in the input catalogue), is always at the corner of a bin.
- The WCS information stored with the output cube created by POLCAL now has three
axes instead of two (the Stokes axis is now described in addition to the two spatial axes).
- A new parameter called TRIMBAD has been added to POLCAL to enable the output cube
to be trimmed to exclude any borders of bad pixels.
- POLBIN and POLVEC can now optionally add RA and DEC columns to their output
catalogues, so long as suitable WCS information is available. See the new parameter
RADEC.
- The WCS FrameSet stored within catalogues by POLBIN and POLVEC now include a
GRID Frame describing the grid co-ordinate system of the Stokes cube.
- POLPLOT now allows the key to be placed inside the vector map by giving a negative
value for the KEYPOS parameter. The text included in the key can be specified using the
Title attribute of parameter KEYSTYLE.
- The default vector scaling used by POLPLOT has been improved in cases where
debiassing causes many zero length vectors to be present.
G.14 V2.0-14
- A new command POLVERSION has been added to check the version number of the
installed package.
- The names of catalogues provided in response to parameter prompts can now contain
shell meta-characters (e.g. $HOME/mycat, ~/mycat, etc.).
- The output cube created by POLCAL in dual-beam mode now covers the union of the
input frames, rather than the intersection.
- A bug has been fixed which could cause the masks displayed by POLKA in dual-beam
mode to jump around as different images were selected.
- A bug has been fixed in POLKA which caused the output NDFs to have the wrong names
if an image was supplied for parameter REFIN. The output images corresponding to the
first input image were stored in files appropriate for the second input image, etc., and the
output images for the final input image were not produced at all.
- The use of the MARGIN parameter by POLPLOT to determine the width of the margins
to place around the annotated axes has been changed. The widths of the margins used to
be specified as fractions of the height or width of the corresponding DATA plot. They are
now given as fractions of the height or width of the current picture.
- The latex and hypertext documents now include the POLSTACK command, previously
only documented in the on-line help library.
G.15 V2.0
- POLCAL can now produce Stokes vectors from single-beam data.
- SUN/223 has been updated to include discussion of single-beam data.
- POLKA will now allow rotation between images in single-beam mode.
- POLPACK (including POLKA) may now be used from the ICL and IRAF cl command
languages.
- POLKA) now has a REFIN parameter which may be used to specify a reference image to
which the other images should be aligned. A reference image specified in this way will
not be processed to create any output files.
- The NEWCOLMAP parameter has been removed from POLKA. POLKA will now use a
private colour map automatically when necessary.
- The Dump and Restore commands in the POLKA File menu now have an option to dump
and restore the feature positions, masks and sky areas for the display image alone to a
text file.
- A new command called POLSIM has been added, which creates simulated intensity data
from a cube of Stokes vectors and a set of template intensity images. This is a useful tool
for investigating noise characteristics within a set of intensity images.
- A new command called POLIMAGE has been added which allows a 1 or 2 dimensional
image to be created from a column of a catalogue.
- The reference direction for Stokes parameters created by POLCAL, POLBIN and POLVEC
has been changed. Prior to V2.0 the reference direction was the WPLATE=0 position ( i.e.
the direction of the fixed analyser). As of V2.0, the reference direction will be north if there
is WCS information available to define north, or the positive Y axis (i.e. the second pixel
axis) otherwise. POLVEC and POLBIN can still read data sets created by earlier versions
of POLPACK which use the previous convention, but will write data sets using the new
convention.
- The angles produced by POLBIN and POLVEC which give the orientation of the
polarization vectors are now referred to the same reference direction as the Stokes
parameters. Previously, these angles were measured anti-clockwise form the positive
X axis ( i.e. the first pixel axis). They are now measured anti-clockwise from the same
reference direction as the Stokes parameters. POLPLOT will automatically determine the
correct convention to use, based on the POLPACK version number stored in the supplied
catalogue.
- The way in which the reference direction is recorded within a POLPACK data file has
been changed. Prior to V2.0, the POLPACK extension item named ANGROT was used.
The reference direction is now specified by the POLANAL co-ordinate Frame added to
the WCS component when POLIMP or POLEXT is run. V2.0 will read ANGROT values
in existing data sets, but will no longer write them.
- The facilities for processing textual values within an import control table used by
POLIMP have been expanded. Concatenation and replacement can now be combined
together, using parentheses to indicate the order in which sub-expressions should be
evaluated. References to keywords may be included in a replacement specification
(on either side of the equals sign) by enclosing the name in parentheses. In fact
such parentheses may include any general character expression, containing nested
replacement specifications, concatentation, etc.
- The choice of default vector scale in POLPLOT has been improved. It now uses the 90%
percentile point, so that 10% of all vectors are at least equal to 1/15th of the length of the
smaller plot dimension.
- The facilities for accessing groups of data files have been changed to allow multiple NDFs
within a single container file to be read.
- A bug has been fixed which limited the number of data files which could be processed by
POLIMP when run as a monolith.
- A bug in POLEXT has been fixed which prevented POLEXT from being able to change an
IMGID value.
- Specifying the keyword STARTHELP when starting POLKA no longer requires POLKA
to use a private colour map.
- A bug in POLKA has been fixed which resulted in a Tcl error being reported when Saving
or Exiting if any of the image names begin with an upper case letter.
- POLEXT and POLIMP no longer abort if non-unique IMGID values are supplied. This
allows IMGID values to be set for extracted O and E ray images.
- POLEXT now allows POLPACK extension items to be set for Stokes cubes and extracted
O or E ray images, as well as raw intensity images. The extension items are now written
to output parameters as well as to the screen.
G.16 V1.1
The handling of World Co-ordinate System (WCS) information within POLPACK has been improved,
and is now consistent with WCS handling within KAPPA V0.13:
- New sections have been added to SUN/223 describing the use of RA/DEC calibrations
within POLPACK, and how to use GAIA to create them.
- POLKA now propagates WCS information from input to output. This makes it possible
to retain WCS information throughout an entire POLPACK reduction.
- The COSYS parameter used by POLPLOT has been replaced by FRAME. A new
parameter called EPOCH has been added to allow the specification of an epoch for
celestial co-ordinate systems.
- POLVEC no longer stores a GRID co-ordinate Frame in the output catalogue (since there
is no data grid defined within a catalogue).
- WCS information can now be read from a FITS or IRAS90 NDF extension if the NDF has
no WCS component.
- A bug has been fixed which caused POLPLOT to display vectors in incorrect positions
when annotating the axes with sky co-ordinates. This bug was not seen if the vectors were
plotted over an existing picture.
- Catalogues created by POLVEC now inherit the Current co-ordinate Frame from
the supplied Stokes cube. Previously the Current Frame was always reset to pixel
co-ordinates.
- The vector positions in the catalogue supplied to POLPLOT must now be given in the
Base Frame of the WCS information stored in the catalogue.
Other non-WCS related changes include:
- Vectors produced by POLPLOT no longer intersect the border.
- If POLKA is used to define a sky region which is then transferred to a second image, the
sky region will be ignored if it does not have an overlap with the second image. In this
case, a warning is issued and the user is asked to specify a new sky region for the second
image.
- The handling of graphical styles within POLPLOT (using parameters STYLE and KEYSTYLE) is
now consistent with KAPPA V0.13. In particular:
-
(1)
- Defaults for unspecified plotting attributes are now read from file
$KAPPA_DIR/style.def.
-
(2)
- The values supplied for STYLE and KEYSTYLE are retained and re-used on
subsequent invocations of POLPLOT (unless new values are given).
-
(3)
- The size of text produced for a given value of the Size attribute is now (roughly)
proportional to the size of the picture being used.
-
(4)
- The default title is now obtained from the TITLE component of the Stokes cube.
Previously it was obtained from the Title attribute of the WCS information.
-
(5)
- A new parameter called “RAY” has been added to POLEXT to allow the RAY
component of the POLPACK extension to be assigned a value.
- The vertical spacing between lines in the key produced by POLPLOT can now be controlled
using the TextLabGap attribute (see parameter KEYSTYLE).
- A new parameter called MARGIN has been added to POLPLOT. It can be used to specify the
widths of the margins left for axis annotation around the vector map.