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8.4.7 weighted

Paints markers like the Density mode, but with optional weighting by an additional coordinate. You can configure how the weighted coordinates are combined to give the final weighted result. The way that data values are mapped to colours is usually controlled by options at the level of the plot itself, rather than by per-layer configuration.

Usage:

   shadingN=weighted weightN=<num-expr> colorN=<rrggbb>|red|blue|...
                     combineN=sum|mean|median|min|max|variance|count|hit

All the parameters listed here affect only the relevant layer, identified by the suffix N.

Associated parameters are as follows:

colorN = <rrggbb>|red|blue|...       (Color)
The color of plotted data.

The value may be a six-digit hexadecimal number giving red, green and blue intensities, e.g. "ff00ff" for magenta. Alternatively it may be the name of one of the pre-defined colors. These are currently red, blue, green, grey, magenta, cyan, orange, pink, yellow, black, light_grey, white.

[Default: red]

combineN = sum|mean|median|min|max|variance|count|hit       (Combiner)
Defines how values contributing to the same pixel are combined together to produce the value assigned to that pixel (and hence its colour).

When a weight is in use, mean or sum are typically sensible choices. If there is no weight (a pure density map) then count is usually better, but in that case it may make more sense (it is more efficient) to use one of the other shading modes instead.

The available options are:

[Default: mean]

weightN = <num-expr>       (String)
Weight coordinate for weighted density shading.

This parameter gives a column name, fixed value, or algebraic expression for the weight coordinate for layer N. The value is a numeric algebraic expression based on column names as described in Section 10.


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STILTS - Starlink Tables Infrastructure Library Tool Set
Starlink User Note256
STILTS web page: http://www.starlink.ac.uk/stilts/
Author email: m.b.taylor@bristol.ac.uk
Mailing list: topcat-user@bristol.ac.uk