arrayquantile
Displays a quantile or quantile range for a set of plotted X/Y array pairs. If a table contains one spectrum per row in array-valued wavelength and flux columns, this plotter can be used to display a median of all the spectra, or a range between two quantiles. Smoothing options are available to even out noise arising from the pixel binning.
For each row, the
xs
and
ys
arrays
must be the same length as each other,
but this plot type does not require all the arrays
to be sampled into the same bins.
The algorithm calculates quantiles for all the X,Y points plotted in each column of pixels. This means that more densely sampled spectra have more influence on the output than sparser ones.
Note: in the current implementation, depending on the details of the configuration and the data, there may be some distortions or missing graphics near the edges of the plot. This may be improved in future releases, depending on feedback.
Usage Overview:
layerN=arrayquantile colorN=<rrggbb>|red|blue|... transparencyN=0..1 quantilesN=<low-frac>[,<high-frac>] thickN=<pixels> smoothN=+<width>|-<count> kernelN=square|linear|epanechnikov|cos|cos2|gauss3|gauss6 joinN=none|polygon|lines horizontalN=true|false xsN=<array-expr> ysN=<array-expr> inN=<table> ifmtN=<in-format> istreamN=true|false icmdN=<cmds>
All the parameters listed here
affect only the relevant layer,
identified by the suffix
N
.
Example:
stilts plot2plane in=xq100sub.fits xs=subWave ys=multiply(subFlux,1./mean(subFlux)) xlabel=Wavelength/nm ylabel='Normalised Flux' x2func=SPEED_OF_LIGHT*1E9*1E-12/x x2label=Frequency/THz layer1=lines shading1=density densemap1=greyscale denseclip1=0.2,1 densefunc1=linear leglabel1=Spectra layer_q13=ArrayQuantile color_q13=DodgerBlue transparency_q13=0.5 quantiles_q13=0.25,0.75 leglabel_q13='Quartile Range' layer_med=ArrayQuantile color_med=blue join_med=lines leglabel_med=Median legend=true legpos=0.95,0.95 xpix=600 ypix=380 xmin=1348 xmax=1358 ymin=-0.2 ymax=2.2
colorN = <rrggbb>|red|blue|...
(Color)
The standard plotting colour names are
red
, blue
, green
, grey
, magenta
, cyan
, orange
, pink
, yellow
, black
, light_grey
, white
.
However, many other common colour names (too many to list here)
are also understood.
The list currently contains those colour names understood
by most web browsers,
from AliceBlue
to YellowGreen
,
listed e.g. in the
Extended color keywords section of
the CSS3 standard.
Alternatively, a six-digit hexadecimal number RRGGBB
may be supplied,
optionally prefixed by "#
" or "0x
",
giving red, green and blue intensities,
e.g. "ff00ff
", "#ff00ff
"
or "0xff00ff
" for magenta.
[Default: red
]
horizontalN = true|false
(Boolean)
true
, y quantiles are calculated
for each pixel column, and
if false
, x quantiles are calculated
for each pixel row.
[Default: true
]
icmdN = <cmds>
(ProcessingStep[])
inN
.
The value of this parameter is one or more of the filter
commands described in Section 6.1.
If more than one is given, they must be separated by
semicolon characters (";").
This parameter can be repeated multiple times on the same
command line to build up a list of processing steps.
The sequence of commands given in this way
defines the processing pipeline which is performed on the table.
Commands may alteratively be supplied in an external file,
by using the indirection character '@'.
Thus a value of "@filename
"
causes the file filename
to be read for a list
of filter commands to execute. The commands in the file
may be separated by newline characters and/or semicolons,
and lines which are blank or which start with a
'#
' character are ignored.
ifmtN = <in-format>
(String)
inN
.
The known formats are listed in Section 5.1.1.
This flag can be used if you know what format your
table is in.
If it has the special value
(auto)
(the default),
then an attempt will be
made to detect the format of the table automatically.
This cannot always be done correctly however, in which case
the program will exit with an error explaining which
formats were attempted.
This parameter is ignored for scheme-specified tables.
[Default: (auto)
]
inN = <table>
(StarTable)
-
",
meaning standard input.
In this case the input format must be given explicitly
using the ifmtN
parameter.
Note that not all formats can be streamed in this way.:<scheme-name>:<scheme-args>
.<
" character at the start,
or a "|
" character at the end
("<syscmd
" or
"syscmd|
").
This executes the given pipeline and reads from its
standard output.
This will probably only work on unix-like systems.istreamN = true|false
(Boolean)
inN
parameter
will be read as a stream.
It is necessary to give the
ifmtN
parameter
in this case.
Depending on the required operations and processing mode,
this may cause the read to fail (sometimes it is necessary
to read the table more than once).
It is not normally necessary to set this flag;
in most cases the data will be streamed automatically
if that is the best thing to do.
However it can sometimes result in less resource usage when
processing large files in certain formats (such as VOTable).
This parameter is ignored for scheme-specified tables.
[Default: false
]
joinN = none|polygon|lines
(QJoin)
The available options are:
none
: displayed quantile ranges are not joinedpolygon
: the area between a line connecting the upper quantiles and a line connecting the lower quantiles is filledlines
: a line of thickness given by thick
is drawn from the center of each quantile range to the next[Default: polygon
]
kernelN = square|linear|epanechnikov|cos|cos2|gauss3|gauss6
(Kernel1dShape)
The available options are:
square
: Uniform value: f(x)=1, |x|=0..1linear
: Triangle: f(x)=1-|x|, |x|=0..1epanechnikov
: Parabola: f(x)=1-x*x, |x|=0..1cos
: Cosine: f(x)=cos(x*pi/2), |x|=0..1cos2
: Cosine squared: f(x)=cos^2(x*pi/2), |x|=0..1gauss3
: Gaussian truncated at 3.0 sigma: f(x)=exp(-x*x/2), |x|=0..3gauss6
: Gaussian truncated at 6.0 sigma: f(x)=exp(-x*x/2), |x|=0..6[Default: epanechnikov
]
quantilesN = <low-frac>[,<high-frac>]
(Subrange)
<lo>,<hi>
)
indicating two quantile lines bounding an area to be filled.
A pair of equal values "a,a
"
is equivalent to the single value "a
".
The default is 0.5
,
which means to mark the median value in each column,
and could equivalently be specified 0.5,0.5
.
[Default: 0.5
]
smoothN = +<width>|-<count>
(BinSizer)
If the supplied value is a positive number it is interpreted as a fixed width in the data coordinates of the X axis (if the X axis is logarithmic, the value is a fixed factor). If it is a negative number, then it will be interpreted as the approximate number of smooothing widths that fit in the width of the visible plot (i.e. plot width / smoothing width). If the value is zero, no smoothing is applied.
When setting this value graphically, you can use either the slider to adjust the bin count or the numeric entry field to fix the bin width.
[Default: 0
]
thickN = <pixels>
(Integer)
quantiles
specifies a single value rather than a pair)
this will give the actual thickness of the plotted line.
If the range is non-zero however, the line may be thicker
than this in places according to the quantile positions.
[Default: 3
]
transparencyN = 0..1
(Double)
[Default: 0
]
xsN = <array-expr>
(String)
The value is an array-valued algebraic expression based on column names as described in Section 10. Some of the functions in the Arrays class may be useful here.
ysN = <array-expr>
(String)
The value is an array-valued algebraic expression based on column names as described in Section 10. Some of the functions in the Arrays class may be useful here.