US Patent 7389001 Reorganizing rectangular layout structures for improved extraction

Scanning a layer of a layout in a first direction and selecting a first rectangle in a scan order, scanning the layer of the layout in a second direction orthogonal to the first direction to find a second rectangle that intersects the first rectangle, and if the second rectangle is found, performing a union of the first and second rectangles to generate a set of non-intersecting rectangles equivalent to the first and second rectangle.