#### Description:

This attribute controls the indentation within the output text produced by the astWrite function. It gives the increase in the indentation for each level in the object heirarchy. If it is set to zero, no indentation will be used. [3]

Type:

  Integer (boolean).

#### Applicability

##### Channel

The default value is zero for a basic Channel.

##### FitsChan

The FitsChan class ignores this attribute.

##### StcsChan

The default value for an StcsChan is zero, which causes the entire STC-S description is written out by a single invocation of the sink function. The text supplied to the sink function will not contain any linefeed characters, and each pair of adjacent words will be separated by a single space. The text may thus be arbitrarily large and the StcsLength attribute is ignored.

If Indent is non-zero, then the text is written out via multiple calls to the sink function, each call corresponding to a single `"` line`"` of text (although no line feed characters will be inserted by AST). The complete STC-S description is broken into lines so that:

- the line length specified by attribute StcsLength is not exceeded

- each sub-phrase (time, space, etc.) starts on a new line

- each argument in a compound spatial region starts on a new line

If this causes a sub-phrase to extend to two or more lines, then the second and subsequent lines will be indented by three spaces compared to the first line. In addition, lines within a compound spatial region will have extra indentation to highlight the nesting produced by the parentheses. Each new level of nesting will be indented by a further three spaces.

##### XmlChan

The default value for an XmlChan is zero, which results in no linefeeds or indentation strings being added to output text. If any non-zero value is assigned to Indent, then extra linefeed and space characters will be inserted as necessary to ensure that each XML tag starts on a new line, and each tag will be indented by a further 3 spaces to show its depth in the containment hierarchy.

##### YamlChan

The default value for a YamlChan is two. Only non-zero values in the range 1-10 are allowed.
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