diff --git a/hoot-core/src/main/cpp/hoot/core/ops/RefRemoveOp.cpp b/hoot-core/src/main/cpp/hoot/core/ops/RefRemoveOp.cpp
new file mode 100644
index 0000000..1eb85fc
--- /dev/null
+++ b/hoot-core/src/main/cpp/hoot/core/ops/RefRemoveOp.cpp
@@ -0,0 +1,157 @@
+/*
+ * 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) 2015, 2017, 2018, 2019 DigitalGlobe (http://www.digitalglobe.com/)
+ */
+#include "RefRemoveOp.h"
+
+// hoot
+#include <hoot/core/util/Factory.h>
+#include <hoot/core/criterion/NotCriterion.h>
+#include <hoot/core/ops/RecursiveElementRemover.h>
+#include <hoot/core/schema/MetadataTags.h>
+#include <hoot/core/visitors/ElementConstOsmMapVisitor.h>
+#include <hoot/core/visitors/ElementOsmMapVisitor.h>
+
+using namespace std;
+
+namespace hoot
+{
+
+HOOT_FACTORY_REGISTER(OsmMapOperation, RefRemoveOp)
+
+class GetRefVisitor : public ElementConstOsmMapVisitor
+{
+public:
+
+ GetRefVisitor(ElementCriterionPtr c) : _criterion(c) {}
+
+ const set<QString>& getRefs() const { return _refs; }
+
+ virtual void visit(const std::shared_ptr<const Element>& e)
+ {
+ if (e->getTags().contains(MetadataTags::Ref1()) && _criterion->isSatisfied(e))
+ {
+ _refs.insert(e->getTags().get(MetadataTags::Ref1()));
+ }
+ }
+
+ virtual QString getDescription() const { return ""; }
+
+private:
+
+ ElementCriterionPtr _criterion;
+ set<QString> _refs;
+};
+
+class RefRemoveVisitor : public ElementOsmMapVisitor
+{
+public:
+
+ RefRemoveVisitor(ElementCriterionPtr c) : _criterion(c) {}
+
+ virtual void visit(const std::shared_ptr<Element>& e)
+ {
+ if (_criterion->isSatisfied(e))
+ {
+ NotCriterion nc(_criterion);
+ RecursiveElementRemover(e->getElementId(), &nc).apply(_map->shared_from_this());
+ }
+ }
+
+ virtual QString getDescription() const { return "Randomly removes elements from a map"; }
+
+private:
+
+ ElementCriterionPtr _criterion;
+};
+
+class UpdateRefVisitor : public ElementOsmMapVisitor
+{
+public:
+
+ UpdateRefVisitor(const set<QString>& refs) : _refs(refs) {}
+
+ QStringList _removeRef1(QStringList refs)
+ {
+ QStringList result;
+ for (int i = 0; i < refs.size(); i++)
+ {
+ if (_refs.count(refs[i]) == 0)
+ {
+ result.append(refs[i]);
+ }
+ }
+
+ return result;
+ }
+
+ virtual QString getDescription() const { return ""; }
+
+ virtual void visit(const std::shared_ptr<Element>& e)
+ {
+ if (e->getTags().contains(MetadataTags::Ref2()))
+ {
+ QStringList ref2 = _removeRef1(e->getTags().getList(MetadataTags::Ref2()));
+ if (ref2.size() == 0)
+ {
+ e->getTags().set(MetadataTags::Ref2(), "none");
+ }
+ else
+ {
+ e->getTags().setList(MetadataTags::Ref2(), ref2);
+ }
+ }
+ e->getTags().setList("REVIEW", _removeRef1(e->getTags().getList("REVIEW")));
+ e->getTags().setList("CONFLICT", _removeRef1(e->getTags().getList("CONFLICT")));
+ e->getTags().setList("DIVIDED1", _removeRef1(e->getTags().getList("DIVIDED1")));
+ e->getTags().setList("DIVIDED2", _removeRef1(e->getTags().getList("DIVIDED2")));
+ }
+
+private:
+
+ const set<QString>& _refs;
+};
+
+RefRemoveOp::RefRemoveOp()
+{
+}
+
+void RefRemoveOp::apply(std::shared_ptr<OsmMap>& map)
+{
+ // get all the REF1 IDs that will be removed
+ GetRefVisitor grv(_criterion);
+ map->visitRo(grv);
+
+ // remove all the elements that meet the criteria
+ RefRemoveVisitor rrv(_criterion);
+ map->visitRw(rrv);
+
+ // remove all the REF1 references that were removed from REF2 entries. This might happen if
+ // you remove all buildings, but there are some POIs remaining that were matched to the buildings.
+ UpdateRefVisitor urv(grv.getRefs());
+ map->visitRw(urv);
+}
+
+}