Major & Mrs Holt's Battle Map of the Ypres Passchendaele Battlefield
Shows;
Modern Roads
Grid Reference system
Location index
Battle lines
Messines Mine Craters
The Gas Attack Location
Bunkers Craters Trenches position
1914-18 Place Names
Demarcation Stones
Memorials
Museums
Cemeteries
Tourist Info

If travelling to the Australian Battlefields see this book, Anzacs on the Western Front which is the best available.