diff --git a/hoot-core/src/main/cpp/hoot/core/conflate/poi-polygon/PoiPolygonCache.h b/hoot-core/src/main/cpp/hoot/core/conflate/poi-polygon/PoiPolygonCache.h
new file mode 100644
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--- /dev/null
+++ b/hoot-core/src/main/cpp/hoot/core/conflate/poi-polygon/PoiPolygonCache.h
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+/*
+ * This file is part of Hootenanny.
+ *
+ * Hootenanny is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * --------------------------------------------------------------------
+ *
+ * The following copyright notices are generated automatically. If you
+ * have a new notice to add, please use the format:
+ * " * @copyright Copyright ..."
+ * This will properly maintain the copyright information. DigitalGlobe
+ * copyrights will be updated automatically.
+ *
+ * @copyright Copyright (C) 2019 DigitalGlobe (http://www.digitalglobe.com/)
+ */
+#ifndef POI_POLYGON_CACHE_H
+#define POI_POLYGON_CACHE_H
+
+// geos
+#include <geos/geom/Geometry.h>
+#include <geos/geom/LineString.h>
+
+// Hoot
+#include <hoot/core/elements/OsmMap.h>
+#include <hoot/core/criterion/ElementCriterion.h>
+#include <hoot/core/schema/OsmSchema.h>
+
+namespace hoot
+{
+
+class PoiPolygonCache;
+
+typedef std::shared_ptr<PoiPolygonCache> PoiPolygonCachePtr;
+
+/**
+ * Cached back class storing POI/Polygon feature comparison info
+ *
+ * The caches used in this class were determined on 9/30/18 running against the regression test:
+ * unifying-tests.child/somalia.child/somalia-test3.child. Further caching could be deemed necessary
+ * for other datasets going forward.
+ */
+class PoiPolygonCache
+{
+
+public:
+
+ PoiPolygonCache(const ConstOsmMapPtr& map);
+ ~PoiPolygonCache();
+
+ /**
+ * Returns the distance from a point node to a polygon way
+ *
+ * @param poly the polygon to measure distance from
+ * @param point the point to measure distance from
+ * @return the distance between the point and polygon or -1.0 if the distance could not be
+ * calculated
+ * @note The distance calc is not backed by a cache, but the geometries used to derive it are.
+ */
+ double getPolyToPointDistance(ConstWayPtr poly, ConstNodePtr point);
+
+ /**
+ * Calculates the area of an element
+ *
+ * @param element the feature to calculate the area of
+ * @return the area of the feature or -1.0 if the area could not be calculated
+ * @note The area calc is not backed by a cache, but the geometries used to derive it are.
+ */
+ double getArea(ConstElementPtr element);
+
+ /**
+ * Determines if a polygon contains a point
+ *
+ * @param poly the polygon to examine
+ * @param point the point to examine
+ * @return true if the polygon contains the point; false otherwise or if the containment could
+ * not be calculated
+ */
+ bool polyContainsPoi(ConstWayPtr poly, ConstNodePtr point);
+
+ /**
+ * Determines if an element intersects another element
+ *
+ * @param element1 the first element to examine
+ * @param element2 the second element to examine
+ * @return true if the two elements intersect; false otherwise or if the intersection could not
+ * be calculated
+ */
+ bool elementIntersectsElement(ConstElementPtr element1, ConstElementPtr element2);
+
+ /**
+ * Determines if an element is of the given type
+ *
+ * @param element the element to determine type membership for
+ * @param type the type to determine membership for the element
+ * @return true if the element is of the requested type; false otherwise
+ * @throws if the requested type is invalid
+ * @todo change type to enum
+ */
+ bool isType(ConstElementPtr element, const QString& type);
+
+ /**
+ * Determines if an element has a given criterion
+ *
+ * @param element the element to examine
+ * @param criterionClassName class name of the ElementCriterion to determine membership of
+ * @return true if the element has the criterion; false otherwise
+ * @throws if the criterion class name is invalid
+ */
+ bool hasCriterion(ConstElementPtr element, const QString& criterionClassName);
+
+ /**
+ * Determines if there exists another poi that is closer than a specified poi to a specified poly
+ *
+ * @param poly the polygon to examine
+ * @param poi the POI to examine
+ * @param poiNeighborIds IDs of POI neighbors to the polygon
+ * @param poiPolyDistance the pre-calculated distance between poi and poly
+ * @return true if at least one other POI is closer to poly than poi; false otherwise
+ * @note The operation becomes more expensive as the search radius is increased.
+ * @todo This only handles ways as polygons and not relations. See #3474.
+ */
+ bool polyHasPoiNeighborCloserThanPoi(ConstWayPtr poly, ConstNodePtr poi,
+ const std::set<ElementId>& poiNeighborIds,
+ const double poiPolyDistance);
+
+ /**
+ * Clears the contents of the cache
+ */
+ void clear();
+
+ /**
+ * Prints information about the caches used by this class
+ */
+ void printCacheInfo();
+
+private:
+
+ ConstOsmMapPtr _map;
+
+ int _badGeomCount;
+
+ // Using QHash here instead of QCache, since we're mostly just storing primitives for values and
+ // they all take up the same amount of space. Tried to use QCache with the geometries, but since
+ // ElementConverter returns a shared pointer and QCache takes ownership, had trouble making it
+ // work. Also, not doing any management of the size of these caches, which may eventually end up
+ // being needed to control memory usage.
+
+ // ordering of the ID keys doesn't matter here; keys are "elementId1;elementId2"
+ QHash<QString, bool> _poiNeighborCloserCache;
+
+ // ordering of the ID keys does matter here; does first element contain second element?; keys are
+ // "elementId1;elementId2"
+ QHash<QString, bool> _elementContainsCache;
+
+ // key is "elementId;type string"
+ QHash<QString, bool> _isTypeCache;
+
+ // key is "elementId;criterion class name"
+ QHash<QString, bool> _hasCriterionCache;
+
+ // key is element criterion class name
+ QHash<QString, ElementCriterionPtr> _criterionCache;
+
+ QHash<ElementId, std::shared_ptr<geos::geom::Geometry>> _geometryCache;
+ QHash<ElementId, std::shared_ptr<geos::geom::LineString>> _lineStringCache;
+
+ QMap<QString, int> _numCacheHitsByCacheType;
+ QMap<QString, int> _numCacheEntriesByCacheType;
+
+ std::shared_ptr<geos::geom::Geometry> _getGeometry(ConstElementPtr element);
+ std::shared_ptr<geos::geom::LineString> _getLineString(ConstWayPtr way);
+
+ ElementCriterionPtr _getCrit(const QString& criterionClassName);
+
+ void _incrementCacheHitCount(const QString& cacheTypeKey);
+ void _incrementCacheSizeCount(const QString& cacheTypeKey);
+};
+
+}
+
+#endif // POIPOLYGONREVIEWREDUCER_H