explanations see below
- The dotted lines show alternate variants
Gonard took into consideration for his proposal for the redoubt and the
advanced position (the blue lines).
- The blue "Napf" bubble on the map shows the
- The blue, green and red areas show the three
main compartments Gonard identified.
- The red pass signs are important railway
- The bold/light black pass signs are important
road passes or passages obligés.