@Article{, author = {Forbus, K. D.}, title = {Qualitative spatial reasoning framework and frontiers}, year = {1995}, }
A metric diagram shows the quantitative aspects of the system, like sizes, as expressed in numbers, etc. Perceptual processes can be applied to it.
The place vocabulary is a qualitative representation of where things are and their shape, as is relevent to the task at hand. A place is a region of space where some important property (e.g. incontact with something) is constant.
Poverty conjecture: There is no problem-independent, purely qualitative representation of space or shape.
Qualitative representations break down: for example, you can represent that a robot can get through a certain door, but if he's carrying something, to figure it out you need to go to the metric level. [p186]
But the qualitative is important too, and the place vocabulary can make a graph of what the robot can do-- it's a task specific representation.
Thus, qualitative and quantitative information needs to be tightly coupled. [187]
FROB is a system that figured out the paths of balls on a landscape and whether they would collide. In FROB, a line segment has a pointer to a symbol (like a surface) as well as numerical info about length and end-points, etc. [189] The MD is necessary for precice predictions, and the PV allows for qualitative reasoning. FROB decomposes space along vertical and horizontal axes. [199]
Kim (1990): made a vocabulary for describing the behavior of fluid.