diff --git a/hoot-core/src/main/cpp/hoot/core/scoring/MatchScoringMapPreparer.cpp b/hoot-core/src/main/cpp/hoot/core/scoring/MatchScoringMapPreparer.cpp
new file mode 100644
index 0000000..3fbcadf
--- /dev/null
+++ b/hoot-core/src/main/cpp/hoot/core/scoring/MatchScoringMapPreparer.cpp
@@ -0,0 +1,104 @@
+/*
+ * 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 "MatchScoringMapPreparer.h"
+
+// hoot
+#include <hoot/core/ops/MapCleaner.h>
+#include <hoot/core/criterion/TagKeyCriterion.h>
+#include <hoot/core/criterion/ElementTypeCriterion.h>
+#include <hoot/core/criterion/TagCriterion.h>
+#include <hoot/core/schema/MetadataTags.h>
+#include <hoot/core/visitors/AddUuidVisitor.h>
+#include <hoot/core/visitors/FilteredVisitor.h>
+#include <hoot/core/visitors/RemoveElementsVisitor.h>
+#include <hoot/core/visitors/RemoveTagsVisitor.h>
+
+namespace hoot
+{
+
+class ConvertUuidToRefVisitor : public ElementOsmMapVisitor
+{
+public:
+
+ virtual void visit(const std::shared_ptr<Element>& e)
+ {
+ if (!e->getTags().contains(MetadataTags::Ref1()) &&
+ !e->getTags().contains(MetadataTags::Ref2()) && e->getTags().contains("uuid"))
+ {
+ QString uuid = e->getTags()["uuid"];
+ if (e->getStatus() == Status::Unknown1)
+ {
+ e->setTag(MetadataTags::Ref1(), uuid);
+ }
+ else if (e->getStatus() == Status::Unknown2)
+ {
+ e->setTag(MetadataTags::Ref2(), uuid);
+ }
+ }
+ }
+
+ virtual QString getDescription() const { return ""; }
+};
+
+MatchScoringMapPreparer::MatchScoringMapPreparer()
+{
+}
+
+void MatchScoringMapPreparer::prepMap(OsmMapPtr map, const bool removeNodes)
+{
+ // if an element has a uuid, but no REF1/REF2 tag then create a REF tag with the uuid. The
+ // 1/2 is determined by the unknown status.
+ ConvertUuidToRefVisitor convertUuidToRef;
+ map->visitRw(convertUuidToRef);
+
+ // #5891 if the feature is marked as todo then there is no need to conflate & evaluate it.
+ std::shared_ptr<TagCriterion> isTodo(new TagCriterion(MetadataTags::Ref2(), "todo"));
+ RemoveElementsVisitor remover;
+ remover.setRecursive(true);
+ remover.addCriterion(isTodo);
+ map->visitRw(remover);
+
+ // add a uuid to all elements with a REF tag.
+ TagKeyCriterion criterion(MetadataTags::Ref1(), MetadataTags::Ref2(), "REVIEW");
+ AddUuidVisitor uuid("uuid");
+ FilteredVisitor v(criterion, uuid);
+ map->visitRw(v);
+
+ if (removeNodes)
+ {
+ // remove all REF1/REF2 tags from the nodes.
+ QStringList keys;
+ keys.append(MetadataTags::Ref1());
+ keys.append(MetadataTags::Ref2());
+ RemoveTagsVisitor removeRef(keys);
+ NodeCriterion nodeCrit;
+ FilteredVisitor removeRefV(nodeCrit, removeRef);
+ map->visitRw(removeRefV);
+ }
+}
+
+}