I am studying a surveyor's map of the neighborhood where I live. The map is on record at the County Clerk's and is known as "the Plat" for my neighborhood. For some of the patios, it notes coordinates for north (or south) and east (or west), relative to some point but clearly not latitude and longitude GPS coordinates. The Plat also gives dimensions of the patios, to the nearest tenth of a foot Written beneath the coordinate numbers is:

(typical)

What does "(typical)" mean in the world of surveying and plats?