That map presents the issue of Markarth and its relation to the westerly borders of Skyrim.
I have seen several maps which present Markarth at that location, which to my eyes appears more to be at the in-game location of Rorikstead. TESV presents Markarth on the extreme western border of Skyrim.
Pray tell, does Bethesda usually post an official map image on their website at a game's release?
Windhelm, Whiterun and Riften are pushed westwards too, and there's no Morthal at all. In fact, Markarth is in the place Morthal should've been.
I guess it's an older map, and only the newest map of Skyrim is updated.