faceting
Element ¶faceting => layer[layers1]* cross layer[layers2]* cross => (unity | nest) (unity | nest) unity => EMPTY nest => variableReference[vars]+ variableReference :ref=ref (sourceVariable | derivedVariable) => EMPTY layer :variable=ref (sourceVariable | derivedVariable) :value :visible=bool? :method[layer_method]=(nest)? :titleVisible=bool? => EMPTY
The faceting
element describes the row, column, and layer
structure of the table. Its cross
child determines the row and
column structure, and each layer
child (if any) represents a
layer. Layers may appear before or after cross
.
The cross
element describes the row and column structure of the
table. It has exactly two children, the first of which describes the
table’s columns and the second the table’s rows. Each child is a
nest
element if the table has any dimensions along the axis in
question, otherwise a unity
element.
A nest
element contains of one or more dimensions listed from
innermost to outermost, each represented by variableReference
child elements. Each variable in a dimension is listed in order.
See Variable Elements, for information on the variables
that comprise a dimension.
A nest
can contain a single dimension, e.g.:
<nest> <variableReference ref="dimension0categories"/> <variableReference ref="dimension0group0"/> <variableReference ref="dimension0"/> </nest>
A nest
can contain multiple dimensions, e.g.:
<nest> <variableReference ref="dimension1categories"/> <variableReference ref="dimension1group0"/> <variableReference ref="dimension1"/> <variableReference ref="dimension0categories"/> <variableReference ref="dimension0"/> </nest>
A nest
may have no dimensions, in which case it still has one
variableReference
child, which references a
derivedVariable
whose value
attribute is
constant(0)
. In the corpus, such a derivedVariable
has
row
or column
, respectively, as its id
. This is
equivalent to using a unity
element in place of nest
.
A variableReference
element refers to a variable through its
ref
attribute.
Each layer
element represents a dimension, e.g.:
<layer value="0" variable="dimension0categories" visible="true"/> <layer value="dimension0" variable="dimension0" visible="false"/>
layer
has the following attributes.
Refers to a sourceVariable
or derivedVariable
element.
The value to select. For a category variable, this is always
0
; for a data variable, it is the same as the variable
attribute.
Whether the layer is visible. Generally, category layers are visible and data layers are not, but sometimes this attribute is omitted.
When present, this is always nest
.