diff --git a/hoot-core/src/main/cpp/hoot/core/algorithms/extractors/AbstractDistanceExtractor.h b/hoot-core/src/main/cpp/hoot/core/algorithms/extractors/AbstractDistanceExtractor.h
index b4ca914..d8f0159 100644
--- a/hoot-core/src/main/cpp/hoot/core/algorithms/extractors/AbstractDistanceExtractor.h
+++ b/hoot-core/src/main/cpp/hoot/core/algorithms/extractors/AbstractDistanceExtractor.h
@@ -23,7 +23,7 @@
* copyrights will be updated automatically.
*
* @copyright Copyright (C) 2005 VividSolutions (http://www.vividsolutions.com/)
- * @copyright Copyright (C) 2015, 2017, 2018, 2019 DigitalGlobe (http://www.digitalglobe.com/)
+ * @copyright Copyright (C) 2015, 2017, 2018, 2019, 2020 DigitalGlobe (http://www.digitalglobe.com/)
*/
#ifndef ABSTRACTDISTANCEEXTRACTOR_H
#define ABSTRACTDISTANCEEXTRACTOR_H
@@ -55,6 +55,9 @@ public:
static std::string className() { return "hoot::AbstractDistanceExtractor"; }
+ AbstractDistanceExtractor() = default;
+ virtual ~AbstractDistanceExtractor() = default;
+
virtual double combinedEnvelopeDiagonalDistance(const OsmMap& map,
const std::shared_ptr<const Element>& target,
const std::shared_ptr<const Element>& candidate) const;