1. A method comprising: determining to store a spatial document index for a corpus of documents, wherein the spatial document index indexes documents in the corpus according to spatial references found within the documents; determining to store a plurality of spatial keyword document indexes for the corpus of documents, wherein the spatial keyword document indexes are derived from the spatial document index, are for a different keyword, and indexes those documents among the corpus that are responsive to that keyword; and intersecting a portion of the spatial document index and selected indexes among the plurality of spatial keyword document indexes to identify a result set of those documents from among the corpus of documents that are responsive to a query.