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8.3.17 handles

Draws a symbol representing the position of an X/Y array plot. Although this may not do a good job of showing the position for a whole X/Y array, which is line-like rather than point-like, it provides a visible reference position for the plotted row.

This plot type is therefore mostly useful in interactive environments like TOPCAT, where the plotted marker can be used for activating or identifying the corresponding table row.

Usage Overview:

   layerN=handles placementN=index|ymax|ymin|xmax|xmin|xymean fractionN=<0..1>
                  sizeN=<pixels> shapeN=filled_circle|open_circle|...
                  shadingN=auto|flat|translucent|transparent|density|aux|weighted <shade-paramsN>
                  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=LRS_NPW_V010_20071101.cdf ys=add(RX1,20*$index)
                     shading=aux auxmap=sron aux=$index
                     icmd='head 8' auxvisible=false legend=false
                     layer0=lines opaque0=2
                     layer1=handles placement1=index fraction1=0.85

fractionN = <0..1>       (Double)
Provides a numeric value in the range 0..1 that may influence where the handle is placed. Currently, this is only relevant for placement=index, where it indicates how far through the array the reference (X,Y) position should be taken (0.0 means the first element, 1.0 means the last). For other values of placement it is ignored.

[Default: 0.5]

icmdN = <cmds>       (ProcessingStep[])
Specifies processing to be performed on the layer N input table as specified by parameter 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 alternatively 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. A backslash character '\' at the end of a line joins it with the following line.

ifmtN = <in-format>       (String)
Specifies the format of the input table as specified by parameter 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)
The location of the input table. This may take one of the following forms: In any case, compressed data in one of the supported compression formats (gzip, Unix compress or bzip2) will be decompressed transparently.
istreamN = true|false       (Boolean)
If set true, the input table specified by the 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]

placementN = index|ymax|ymin|xmax|xmin|xymean       (XYArrayPlacement)
Determines where the handle will be positioned in relation to the X/Y array values.

The available options are:

[Default: index]

shadingN = auto|flat|translucent|transparent|density|aux|weighted <shade-paramsN>       (ShapeMode)
Determines how plotted objects in layer N are coloured. This may be influenced by how many objects are plotted over each other as well as the values of other parameters. Available options (Section 8.4) are: Each of these options comes with its own set of parameters to specify the details of how colouring is done.

[Default: auto]

shapeN = filled_circle|open_circle|...       (MarkerShape)
Sets the shape of the marker that is drawn to identify the handle position.

The available options are:

[Default: fat_square]

sizeN = <pixels>       (Integer)
Sets the size of the marker that is drawn to identify the handle position. The unit is pixels, in most cases the marker is approximately twice the size of the supplied value.

[Default: 4]

xsN = <array-expr>       (String)
Array giving the X coordinate array for each line. In most cases, if a blank value is supplied but Y values are present then a suitable linear sequence, of the same length as the Y array, is assumed.

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)
Array giving the Y coordinate array for each line. In most cases, if a blank value is supplied but X values are present then a suitable linear sequence, of the same length as the X array, is assumed.

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.


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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@jiscmail.ac.uk