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A brief summary of improvements these windows offer over the classic
plot windows is:
-
New Sky Coordinate Plot
-
- Choice of projection: Sin (rotatable), Aitoff, Plate Carrée
- Data and view sky coordinate systems selected separately:
options are equatorial, galactic, supergalactic, ecliptic
- Sky coordinate grid labelled and visible at all zooms
-
New data plot options
-
- vectors
- ellipses (with position angle)
- pair, triple, ... data point lines/polygons
- contours
- variable size markers
-
Improved interactive response
-
- In 2d and sky plots mouse wheel zooms around cursor position
- In 2d and sky plots you can drag the plot around
- In 3d plots right mouse button recentres cube on selected point
- In 3d plots zooming zooms data in the cube rather than enlarging the
cube wireframe itself
- Many controls are sliders which update the plot as you slide
-
Better support for large datasets
- Several features have been introduced to provide more meaningful
visualisation of large datasets. Improved density-like plots
and contours give you better ways to understand plots containing
many more points than there are pixels to plot them on.
There is separately some improvement in scalability:
up to roughly 10 million points is currently feasible depending
on available memory etc, though it depends what you're doing.
However, I hope to improve this limit in future.
-
New plot shading modes
- Density colour coding for all plot types,
with colour map either absolute or modifying dataset base colour.
Flat, transparent and aux colour coding still available as before.
-
Improved axis labelling
-
- Choice of font size and style
- Option of LaTeX input for non-ASCII characters etc
- Log axes labelled better
- Minor tick option
-
Legend options
- External or manually positioned internal placement.
-
Analytic function plotting in 2D
- Plot functions of X or Y coordinate using TOPCAT expression language.
The new windows allow you to assemble a stack of layers representing
different plot types of different data sets on the same axes.
The user interface for controlling this is quite a bit different than
for the classic plot windows, and is described in the subsequent sections.
However, making a simple plot is still simple: select a table, select
the columns, and you're off.
Some features not currently available in the layer plots
include the 1-d histogram, the stacked line plot, and true RGB
density maps (though density shading modes will often do as good or
a better job).
The intention is to introduce these in a future release.
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Next: Window Overview
Up: Layer Plot Windows
Previous: Layer Plot Windows
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