Ottoman space is not flat. The toponyms that appear in Ottoman records are nodes in a hierarchical administrative vision of provinces, subprovinces, districts, and townships. A complete gazetteer of Ottoman space must represent not just the geographic coordinates associated with place names but also their place in the imperial schema. A gazetteer of this kind will be a resource not just for the reconciliation of historic place names but for more comprehensive study of the Ottoman administrative gaze. It would permit scholars more accurately to estimate, for example, how many kazas the empire contained in any given year, and to situate assertions about the past in a clearer context. A tool like this would be especially useful in studies employing quantitative evidence. A gazetteer of this kind requires an ontology, which is a controlled classification schema and a set of rules specifying the relationship between elements of that schema. The best practice in linked data is to employ an existing vocabulary; geonames offers a hierarchy of administrative districts that generally corresponds to the needs of an Ottoman gazetteer. Many of the puzzles of Ottoman history are products of its administrative exceptions, however. The nature of a vilayat-? mümtaze cannot clearly be captured by geonames or other generic schemas. Ottomanists need to develop their own ontology. This paper describes a basic approach to this task, using linked data tools. Representing the Ottoman administrative hierarchy is a relatively straightforward matter of specifying the rule and a limited set of exceptions. The greater challenge is representing change over time in the gazetteer. This is a problem that I have not seen a clear path to tackle, and I hope in this paper to propose a method to periodize this representation.