Base Plat
A drawing containing only those details essential to the identification of the legal subdivisions shown on it Under the manuals of surveying instruction preceding that of 1930, the base plat also contained all cultural and topographic features thought to be desirable. The 1930 and 1947 Manuals of Surveying Instructions called for the use of transparent color overlays to show these features when required. Overprints are not needed where such features may be readily shown on the base drawing without risk of obscuring any essential cadastral data. Color overlays have been used with base plats of areas surveyed by photogrammetric methods.