Description: Footprints for all buildings and out buildings in Allegheny County. Buildings are captured by following the edge of the roof line. All near orthogonal corners are square. Interum roof lines, such as dormers, are not shown. Minor structures such as carports, decks, patios, stairs, etc. which are part of the structure are not shown. Buildings less than 400 square feet are not shown. Structures which cannot be clearly defined as Industrial/Commercial; Residential; Public; or Out BUildings should be flagged as such for later categorization.