  Many different tagsets are used in existing corpora; these tagsets vary
according to the objectives of specific projects (which may be as far apart as
robust parsing vs. spelling correction). In many situations, however, one would
like to have uniform access to the linguistic information encoded in corpus
annotations without having to know the classification schemes in detail. This
paper describes a tool which maps unstructured morphosyntactic tags to a
constraint-based, typed, configurable specification language, a ``standard
tagset''. The mapping relies on a manually written set of mapping rules, which
is automatically checked for consistency. In certain cases, unsharp mappings
are unavoidable, and noise, i.e. groups of word forms {\sl not} conforming to
the specification, will appear in the output of the mapping. The system
automatically detects such noise and informs the user about it. The tool has
been tested with rules for the UPenn tagset \cite{up} and the SUSANNE tagset
\cite{garside}, in the framework of the EAGLES\footnote{LRE project EAGLES, cf.
\cite{eagles}.} validation phase for standardised tagsets for European
languages.
