Covering Hemel Hempstead, St. Albans, Hatfield & Welwyn Garden City, this map also features parts of both The Chilterns Area of Outstanding Natural Beauty & Watling Chase community forest. With this map you will receive a code for use on your i OS or Android smartphone or tablet. Find our more at Mobile Download FAQ. The OS Explorer map for St Albans & Hatfield is available in both the standard paper version & weatherproof ' Active' version.