About Parcel Maps
In the public sector, governments administer and make policy through the creation of and maintenance of land records that are associated with a parcel of land. Thus the parcel is often the basic administrative unit of local government.

Parcel maps are developed at many levels of government and by the private sector. Parcel maps help facilitate administration, zoning, building and site development, flood control, lake and stream erosion control, and the planning, design and construction of roads and public works. In the private sector, parcel maps are useful to attorneys, appraisers, assessors, surveyors, engineers, and utility corporations as a means to inventory land holdings and index land records.

Parcel maps are unique because they have no federal or state oversight with their development. Historically, most parcel maps have been developed at the local level, where content, procedures, methods, and standards widely vary. As a result, many types of parcel maps have been produced in order to meet a variety of purposes. The very definition of "parcel" or "parcel map" can be controversial and confusing.

As mentioned, parcel definitions vary depending on the application. Differences can be caused by factors including: attempts to represent separate parcels under the same ownership, existence of administrative boundaries, movement of natural features that define boundaries, changes in land tenure and land use, varying levels of interest in land, and status of publicly owned lands. These variations and multiple definitions complicate data use and data sharing.

The most common parcel maps found today are local government tax parcel maps. Tax maps are used for locating and describing properties that are linked to owners, tax bills, and other assessment information. Because of these needs, tax maps typically represent a generalized portrayal of parcel locations and dimensions rather than a highly accurate representation of legal ownership.

Parcel Mapping in Wisconsin
The Wisconsin Land Information Program (WLIP) has contributed significantly to recent parcel mapping activities. Parcel maps are recognized as a key "foundational element" of the WLIP because of their many uses in local government. It is primarily due to the opportunities presented by the Program and its funding that local governments have been able to focus greater efforts on updating and automating parcel information. Contact the WLIB for more information.