Legal Descriptions - Lot and Block System Flashcards Lot and Block System (section, block, and lot) A type of legal description used for platted property. The description states only the property's lot number and block number in a particular subdivision.Requires consultation of a plat map to find exact location sec, blk, lotsection, block, lot Topographic map (contour or topo map)-shows elevation of a particular section of land-purpose is primarily to show things such as water run-off Monument system-often used to describe multi-acre tracts of land Some Key Math1 yard = 3 feet1 square yard = 9 sq ft1 acre = 43,560 sq ft1 mile = 5280 ft1 section = 640 acres Builder's acre is how many sq ft?40,000 usually, which may be used by developers to describe lots for new construction.It is NOT a LEGAL acre Plat map (plot plan or a recorded plat)-detailed survey map of a subdivision, used most often by developers, that is recorded in the public records of the county where the land is located To get linear feet, you add all lengthse.g. a backyard is 70' x 50'the linear feet of the backyard is70 + 70 + 50 + 50 = 240