Strictly speaking, the non-north-pointing uses of the "Four Points" spell are borderline canon/deuterocanon -- "Point me" can be used in the official Harry Potter video games (which are often cited as valid sources) to find things other than north.
As far as mindscapes are concerned, well, canon says nothing either way. But in this particular case, you only have Dumbledore's assumption that Doug's is a function of Occlumency, which honestly, Doug is not trained in. To the extent his mental defenses have undergone any training at all, they have been shaped by the philosophy of his teammate Psyche, who approaches the subject much like the Soviet Union approached the border between East and West Berlin.
As for the existence of a mindscape at all in Doug's head, any number of real-world non-magical mental disciplines -- some of which have shown up in Potter fanfics as part of Occlumentic practices -- involve creating mindscapes to navigate. The one I'm most familiar with is the recall technique called http://en.wikipedia.org/wiki/Method_of_loci]the "Memory Palace", aka "method of loci", which dates back to the ancient Greeks. Doug has dabbled in many of these techniques -- they're as much responsible for his "semi-eidetic" memory as his neurological mutations are.
-- Bob
---------
Then the horns kicked in...
...and my shoes began to squeak.
As far as mindscapes are concerned, well, canon says nothing either way. But in this particular case, you only have Dumbledore's assumption that Doug's is a function of Occlumency, which honestly, Doug is not trained in. To the extent his mental defenses have undergone any training at all, they have been shaped by the philosophy of his teammate Psyche, who approaches the subject much like the Soviet Union approached the border between East and West Berlin.
As for the existence of a mindscape at all in Doug's head, any number of real-world non-magical mental disciplines -- some of which have shown up in Potter fanfics as part of Occlumentic practices -- involve creating mindscapes to navigate. The one I'm most familiar with is the recall technique called http://en.wikipedia.org/wiki/Method_of_loci]the "Memory Palace", aka "method of loci", which dates back to the ancient Greeks. Doug has dabbled in many of these techniques -- they're as much responsible for his "semi-eidetic" memory as his neurological mutations are.
-- Bob
---------
Then the horns kicked in...
...and my shoes began to squeak.