"GeoCouch: Geospatial queries with CouchDB" is a blog post by Volker Mische about a prototype geospatial extension to CouchDB, known as GeoCouch. The post provides details about GeoCouch's structure, which is composed of an indexer and a query processor, it also explains this tool only currently supports POINT geometry and bounding box searches. The post further details the interaction between the indexer, CouchDB, and how geometries are stored and updated.
GeoCouch: Geospatial queries with CouchDB | vmx - the blllog.