2>
<p>The need for TongFen comes up frequently with certain types of geographies. Census geographies is one such example. In some cases these data sources come with their own correspondence files that go beyond geographic matchup but also join regions to alleviate data integrity problems like geocoding issues.</p>
<p>In such cases it can be worthwhile to wrap data acquisition and TongFen into one convenience function, and also extend the TongFen <em>method</em> parameter to allow for external correspondence