Land-Based Classification Standards–Federal Role
Jerry Everett and Chimai Ngo	© & Author Info

Standard Land Use Coding Manual

In 1965, the Federal Highway Administration and the Department of Housing (then the Bureau of Public Roads and the Urban Renewal Administration, respectively) published the Standard Land Use Coding Manual (SLUCM). The manual provided a detailed listing of land-use categories with numeric codes assigned to them. The categories were based on the Standard Industrial Classification (SIC) system. This coding procedure became the typical method for land-use coding in urban areas throughout the country. The manual was reprinted in 1972. Beginning in the late 1970s, the manual was used less frequently because land-use planning emphasized short-term, small-scale projects and the long-term horizon for planning was de-emphasized.

The 1965 SLUCM provided a general numeric coding scheme that used two, three, four, or more digits to identify land-use activities and an additional two to eight digits to identify ownership, type of structure the activity is housed in, auxiliary use codes for secondary land uses, etc. The primary emphasis of the SLUCM coding was to provide an exhaustive set of land uses derived from the SIC codes and a limited set of attribute data to further define some of the land-use categories. The manual provided illustrations of three attributes: ownership types; type of structures for residential uses; and crop types for farm uses.

The coding system as developed in 1965 was a recommended system; participating agencies or programs were not required to use it.

Project Participants:

In 1994 several federal agencies along with APA embarked on a cooperative agreement to develop new standards. The following agencies have funded this effort:

• Federal Highway Administration
• Department of Housing and Urban Development
• Federal Aviation Administration
• Department of Defense
• Bureau of Transportation Statistics
• Department of Agriculture
• Federal Emergency Management Agency
• American Planning Association

Representatives from each of the funding agencies serve on Steering Committee to guide the scope of the study. The FHWA representative also serves as the chair of the Steering Committee. In addition, over a hundred interested planners and land-use data users have been nominated to serve on a technical advisory panel. In discussion with TAP members and input from others, the following primary purposes surfaced.

1. To develop an up-to-date and comprehensive list of land uses, and a flexible approach to categorizing new land uses in urban, suburban, and rural areas.
2. To provide a system of coding land uses which is consistent with and supporting of recent legislation. New Federal initiatives -- such as the Clean Air Act Amendments of 1990 (CAAA), the Environmental Justice Order and the Intermodal Surface Transportation Efficiency Act (ISTEA) -- and virtually all environmental data used to do geographically based policy analyses require land-use/land-cover data that is specific to program needs. To address such varying levels of detail, the update may have several parts, and each part could address a specific area of concern (e.g., transportation, environmental, economic, coastal management, etc.).
3. To facilitate the sharing of computer-based land-use/land-cover data by standardizing the coding system. Any sharing of such data will have to recognize the differences of studies between regulatory jurisdictions, as well as the issue of spatial resolution and levels of detail. The update, if necessary, will include computer-based conversion packages to assist in such conversion/sharing of land-use data.
4. To develop a coding system that will recognize the source of data or nature of data acquisition. For instance, land-use/land cover data could be acquired through digital images derived from remote sensing; digital or manual data derived from the interpretation of aerial photography, or site information gathered from surveys that include characteristics such as ownership, parcel boundaries, zoning, etc. Coding schemes should be easily adaptable to address such differences in scale.
5. To make possible periodic updates so that each part of the manual could be updated, revised, or modified independent of other parts.
6. To enable regional agencies (e.g., Councils of Government (COGs), Metropolitan Planning Organizations (MPOs), Regional Planning Agencies and Regional Special Purpose Districts) to acquire or disseminate land-use/land-cover data to local city or county governments by using a well-defined coding scheme to satisfy the needs of municipal planning and management, small area forecasts, monitoring regional trends, etc.
7. To create a coding system that is easily adaptable for use in Geographic Information Systems (GISs). The widespread use of GISs and other computer-based systems for spatial data analyses has put a premium on the use of existing available data and the portability of such data between various computer systems, as well as the aggregation of land-use categories and some uniformity and consistency in coding types.

The complete working paper, to be published by the American Planning Association, will be available at http://www.planning.org/lbcs.

Jerry Everett and Chimai Ngo
Federal Highway Administration
U.S. Department of Transportation