Plots position density contours. This provides another way (alongside the auto, density and weighted shading modes) to visualise the characteristics of overdense regions in a crowded plot. It's not very useful if you just have a few points.
A weighting may optionally be applied to the quantity
To do this, provide a non-blank value for the
coordinate, and use the
parameter to define how the weights are combined
The contours are currently drawn as pixels rather than lines so they don't look very beautiful in exported vector output formats (PDF, PostScript). This may be improved in the future.
layerN=contour colorN=<rrggbb>|red|blue|... combineN=sum|mean|median|stdev|min|max|count nlevelN=<int-value> smoothN=<pixels> thickN=<pixels> scalingN=linear|log|equal zeroN=<number> <pos-coord-paramsN> weightN=<num-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
<pos-coord-paramsN>give a position for each row of the input table. Their form depends on the plot geometry, i.e. which plotting command is used. For a plane plot (
plot2plane) the parameters would be
yN. The coordinate parameter values are in all cases strings interpreted as numeric expressions based on column names. These can be column names, fixed values or algebraic expressions as described in Section 10.
stilts plot2plane in=tgas_source.fits x=phot_g_mean_mag y=phot_g_mean_flux_error ylog=true xmax=14 ymin=10 layer1=mark shading1=density densemap1=greyscale layer2=contour scaling2=log nlevel=6
colorN = <rrggbb>|red|blue|...(Color)
The standard plotting colour names are
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,
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 "
giving red, green and blue intensities,
0xff00ff" for magenta.
combineN = sum|mean|median|stdev|min|max|count(Combiner)
meanwhich traces the mean values of a quantity and
sumwhich traces the weighted sum. Other values such as
medianare of dubious validity because of the way that the smoothing is done.
This value is ignored if the weighting coordinate
is not set.
The available options are:
sum: the sum of all the combined values per bin
mean: the mean of the combined values
median: the median
stdev: the sample standard deviation of the combined values
min: the minimum of all the combined values
max: the maximum of all the combined values
count: the number of non-blank values per bin (weight is ignored)
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 "
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.
inN = <table>(StarTable)
-", meaning standard input. In this case the input format must be given explicitly using the
ifmtNparameter. Note that not all formats can be streamed in this way.
<" 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)
inNparameter will be read as a stream. It is necessary to give the
ifmtNparameter 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.
nlevelN = <int-value>(Integer)
scalingN = linear|log|equal(LevelMode)
The available options are:
linear: levels are equally spaced
log: level logarithms are equally spaced
equal: levels are spaced to provide equal-area inter-contour regions
smoothN = <pixels>(Integer)
thickN = <pixels>(Integer)
weightN = <num-expr>(String)
The value is a numeric algebraic expression based on column names as described in Section 10.
zeroN = <number>(Double)