People in Southwest Virginia often think of Northern Virginia as a foreign territory, a place where demographics and politics tend to differ in dramatic ways from their part of the commonwealth. Of course, Southwest Virginia is also an animal unto itself, one where some communities limp along when compared with the state’s more prosperous and bustling regions. And that’s especially true when the Roanoke Valley is excluded from the equation, which was the case in a demographic analysis released last month by the Weldon Cooper Center for Public Service at the University of Virginia.