A map unit is a spatial category which contains a vegetation type or group of co-occurring vegetation types. The map unit is commonly an item in a map legend and is delineated on the map by means of one to many polygons. NVIS

a collection of areas defined and named in terms of their soil components or miscellaneous areas or both

a collection of areas defined and named the same in terms of their soil and/or nonsoil areas

a collection of areas defined in terms of similar patterns of soils and/or nonsoil areas

a collection of soil areas or miscellaneous areas delineated in a soil map or soil survey

a set of map delineations designated by a single name, and representing a single legend category.

The name given a wetland polygon.  Can be made up of one or more map components.

maps of natural resources such as vegetation, soils and landform are usually prepared by examining aerial or satellite images of the landscape. Each uniform pattern on the images is termed a map unit. The unit may represent a uniform landform, soil or vegetation type, or a similar combination of these. The natural resource/s that characterise a map unit are usually determined from surveys on the ground to collect data from a number of different areas that represent the unit