What Midbar is discussed?
Radak: It is Midbar Yam Suf ("va'Yis'u mi'Hor ha'Har Derech Lisvov Es Eretz Edom" (Bamidbar 21:4).
Where did Yisrael go in the Midbar?
Rashi: From west to east, along the southern border of Edom and Mo'av. 1
In which direction did we surround Mo'av?
Rashi: We went around the south, and when we came to southeast corner, we turned to the north to surround its eastern border.
Aderes Eliyahu (Bamidbar 22:36, Tinyana), ha'Emek Davar (Bamidbar 21:10): Mo'av is on the eastern border of Kena'an. We went north along its border.
Why does it say "va'Yachanun"?
Radak: The final Nun is extra. We find like this - Tishmerun, Tizkerun.
