Campbell Scientific LoggerNet Datalogger Support Software - Manual (Page 501)

Appendix B. Campbell Scientific File Formats
attributes. The document is expected to have a single root element which can
contain any number of sub-elements which in turn can contain any number of
sub-elements and/or other content. Every element must have a name and can
optionally have a set of attributes which are a collection of name/value pairs
where the name is unique.
Most XML files will begin with a sequence that identifies the file as XML and
can also specify the character encoding of the file (if no character encoding is
specified, the file is assumed to use the UTF-8 unicode character encoding).
The following example shows this sequence as it will appear in CSIXML data
files:
<?xml version=“1.0” standalone=“yes”?>
XML is derived from SGML (Standard Generalized Markup Language) and
shares much of the same syntax rules as SGML. HTML (HyperText Markup
Language) is also derived from SGML and, as a result, also has a significant
resemblance to XML. XML elements are represented using tags. A tag begins
with the less than character (<) followed by the name of the element. If that
element has attributes, these will be expected to follow the element name with
a name=“value” syntax. At least one white space character is expected to
separate the attributes and the element name. Other than this rule, XML parsers
ignore the presence of whitespace within the tag. If an element is empty
(contains no child elements), the tag can end with a slash character (/) and the
greater than character (>). If the element is not empty (the element does have
child elements), the tag is expected to end with a greater than character (>) and
the child elements or element content will be expected to follow. In this case,
the end of the element is marked by another less-than character (<) followed by
a slash character (/), the element name, and a greater than character (>).
The following example shows how an element with content may appear:
<v n=“pi”>3.14159</v>
The following example shows how an empty element may appear:
<v n=“emptyString”/>
Because XML reserves special characters for its mark-up language, pre-defined
entities are recognized by all XML parsers. These entities include the
following:
TABLE B-2. Pre-Defined XML Entities
&lt; less than sign (<)
&gt; greater than sign (>)
&amp; ampersand (&)
&quot; double quote (“)
&apos; apostrophe or single quote (‘)
B-7