  A \emph{generic rectangular layout} (for short, \emph{layout}) is a
subdivision of an axis-aligned rectangle into axis-aligned rectangles, no four
of which have a point in common. Such layouts are used in data visualization
and in cartography. The contacts between the rectangles represent semantic or
geographic relations. A layout is weakly (strongly) \emph{aspect ratio
universal} if any assignment of aspect ratios to rectangles can be realized by
a weakly (strongly) equivalent layout. We give combinatorial characterizations
for weakly and strongly aspect ratio universal layouts. Furthermore, we
describe a quadratic-time algorithm that decides whether a given graph is the
dual graph of a strongly aspect ratio universal layout, and finds such a layout
if one exists.
