diff --git a/src/pg/sql/19_contour.sql b/src/pg/sql/19_contour.sql
index 2dd9f62..784779e 100644
--- a/src/pg/sql/19_contour.sql
+++ b/src/pg/sql/19_contour.sql
@@ -1,3 +1,5 @@
+DROP FUNCTION cdb_contour(geometry[],numeric[],numeric,integer,integer,integer,integer);
+
 CREATE OR REPLACE FUNCTION CDB_Contour(
     IN geomin geometry[],
     IN colin numeric[],