Complex sentence: The set includes a detailed fold-out bird's-eye-view of the town, which matches the diagrammatic, keyed location and street map, which cross-references with one of the booklets to describe the major features of the city.
Split into simpler sentences: The set includes a detailed fold-out bird's-eye-view of the town, which matches the diagrammatic, keyed-location street map. It is cross-referenced with one of the booklets to describe the major features of the city.