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This control is experimental.
As currently implemented it lacks some important features.
It may be improved or withdrawn in a future version.
The Spectrogram Layer Control (
)
plots a spectrum at successive (usually, but not necessarily,
regularly-spaced) points in a time series.
It is only available for the experimental
Time Plot Window.
Time Plot window with a Spectrogram layer
This control has two tabs, Data and Style,
described below.
Spectrogram control Data tab
The Data tab allows you to specify which values from
a table will generate a spectrogram.
It has the following fields:
-
Table
- The table supplying the data.
-
Time
- A table column or expression giving the epoch coordinate at which
spectra are located.
This should normally be a time-typed column;
if it is simply of numeric type it will be interpreted as seconds
since 1 Jan 1970.
-
Spectrum
- An array-valued table column giving the spectral data.
-
TimeWidth
- A table column or expression (variable or constant) giving the
temporal coverage of a plotted spectrum.
If not filled in, it is assumed to be the most common
(median) difference between time points.
-
Row Subset
- The subset for which the spectrum should
be plotted. To plot multiple subsets (not usually useful with this
kind of plot) you would need multiple spectrogram layer controls
in the stack.
Spectrogram control Style tab
The Style allows you to configure the way the spectrogram
is plotted. It has the following fields:
-
Shader
- Select the colour map from a list of options.
-
Shade Log
- Whether the aux scale should map linearly or logarithmically
into the colour map.
-
Shade Flip
- Whether the aux scale should map forwards or backwards
into the colour map.
-
Null Colour
- What colour should be used to represent spectral samples with a null
value.
If the associated Hide option is selected,
then those points will not appear in the plot at all (they will be
transparent).
Next Previous Up Contents
Next: Function Layer Control
Up: Layer Controls
Previous: Histogram Layer Control
TOPCAT - Tool for OPerations on Catalogues And Tables
Starlink User Note253
TOPCAT web page:
http://www.starlink.ac.uk/topcat/
Author email:
m.b.taylor@bristol.ac.uk
Mailing list:
topcat-user@bristol.ac.uk