A metric gauge on a set is a maximal collection of metrics on the
set such that the identity map between any two metrics from the
collection is locally bi-Lipschitz. We characterize metric gauges that
are locally branched Euclidean and discuss an obstruction to removing
the branching. Our characterization is a mixture of analysis,
geometry, and topology with an argument of Yu. Reshetnyak to produce
the branched coordinates for the gauge.
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