diff --git a/opm/parser/share/keywords/G/GRIDUNIT b/opm/parser/share/keywords/G/GRIDUNIT
index 718cb845d..8209d6b19 100644
--- a/opm/parser/share/keywords/G/GRIDUNIT
+++ b/opm/parser/share/keywords/G/GRIDUNIT
@@ -1,3 +1,3 @@
 {"name" : "GRIDUNIT" , "size" : 1, "items" : 
-        [{"name" : "LengthUnit"  , "value_type" : "STRING" , "default" : "METRES"}]
-}
\ No newline at end of file
+        [{"name" : "LengthUnit"  , "value_type" : "STRING" , "default" : "METRES"},
+         {"name" : "MAP"         , "value_type" : "STRING"}]}