Improve documentation
Change-Id: I265f6b67811aab93e973a1ae5365873a335fdda0
diff --git a/Readme.pod b/Readme.pod
index cc8c519..26358fc 100644
--- a/Readme.pod
+++ b/Readme.pod
@@ -1,5 +1,3 @@
-__END__
-
=pod
=encoding utf8
@@ -481,26 +479,64 @@
=head1 METADATA SUPPORT
L<KorAP::XML::Krill> has built-in importer for some meta data variants
-developed in the KorAP project that are part of the KorAP preprocessing pipeline.
+that are part of the KorAP preprocessing pipeline.
=over 2
-=item I5 - Meta data for all I5 files
+=item B<I5> - Meta data for all I5 files
-=item Sgbr - Meta data from the Schreibgebrauch project
+=item B<Sgbr> - Meta data from the Schreibgebrauch project
-=item Gingko - Meta data from the Gingko project in addition to I5
+=item B<Gingko> - Meta data from the Gingko project in addition to I5
-=item ICC - Meta data for the ICC in addition to I5
+=item B<ICC> - Meta data for the ICC in addition to I5
-=item NKJP - Meta data for the NKJP corpora
+=item B<NKJP> - Meta data for the NKJP corpora
=back
-More importers are in preparation.
New meta data importers can be defined in the C<KorAP::XML::Meta> namespace.
See the built-in meta data importers as examples.
+The I5 metadata definition is based on TEI-P5 and supports C<E<lt>xenoDataE<gt>>
+with C<E<lt>meta<gt>> elements like
+
+ <meta type="..." name="..." project="..." desc="...">...</meta>
+
+that are directly translated to Krill objects. The supported values are:
+
+=over 2
+
+=item C<type>:
+
+=over 4
+
+=item C<string>: String meta data value
+
+=item C<keyword>: String meta data value, that can be given multiple times
+
+=item C<text>: String meta data value, that is tokenized and can be searched as token sequences
+
+=item C<date>: Date meta data value (as "yyyy/mm/dd" with optional granularity)
+
+=item C<integer>: Numerical meta data value
+
+=item C<attachement>: Non-indexed meta data value (only retrievable)
+
+=item C<uri>: Non-indexed attached URI, takes the desc as the title for links
+
+=back
+
+=item C<name>: The key of the meta object
+
+=item C<project> (optional): A prefixed namespace of the key
+
+=item C<desc> (optional): A description of the key
+
+=item text content: The value of the meta object
+
+=back
+
=head1 About KorAP-XML