Locates a long,lat given a pre-processed shape file

gistfile1.clj

(defn locate-point
  "Given a map of shapes see (process-shape-file), locate the entry that
   contains the given lat/long, optionally filtered by keys."
  ([shapes long lat] (locate-point shapes lat long nil))
  ([shapes long lat keys]
     (let [locs (if keys (select-keys shapes keys) shapes)
           point (.. JTSFactoryFinder (getGeometryFactory)
                     (createPoint (Coordinate. long lat)))
           flocs (first
                  (filter (fn [x]
                            (let [geom (:geom (val x))]
                              (if (nil? geom) false (.contains geom point))))
                          locs))]
       (if flocs (val flocs)))))