Out of a total of 10 result rows in view Χάρτης, 1 rows did not have their field_latlon set and therefore could not be shown on the map. The first row that could not be located was row #8 (nid #8019: ΤΡΕΛΟ ΚΟΥΤΑΛΙ (CRAZY SPOON) CAPPA TONEA ANA MARIA). You can improve execution efficiency by using the Views UI to add an "is not empty" filter for field_latlon.
