diff --git a/PotreeConverter/include/XYZPointReader.hpp b/PotreeConverter/include/XYZPointReader.hpp
index ca78adba..4882dddc 100644
--- a/PotreeConverter/include/XYZPointReader.hpp
+++ b/PotreeConverter/include/XYZPointReader.hpp
@@ -97,7 +97,7 @@ class XYZPointReader : public PointReader{
 				}
 
 				int i = 0;
-				for(const auto &f : format) {
+				for(const auto &f : this->format) {
 					string token = tokens[i++];
 					if(f == 'r'){
 						max = std::max(max, stof(token));