A subdivision map is a division of a tract of land into smaller parcels or lots. The number of lots or parcels of land is determined by local ordinances and state laws. A subdivision is usually a two-step process which requires a tentative map and a final map. The tentative map is for the purposes of showing the proposed improvement and lot configuration. The final map is either a parcel map for four parcels or less, or a tract map which is for five lots or more, each conforming to city and county governmental conditions.
When dividing a parcel of land, typically the main reasons are to develop the smaller lots for real estate transactions, to legally separate out a section of land for commercial use, or to construct different building types on certain parcels. A lot line adjustment is the process that is used to change property lines of existing parcels. All of these items are highly regulated by State and Local Laws.