5.2 STANDARDIZING THE DESCRIPTIONS AND CODING OF PROPERTY CHARACTERISTICS
The sharing of land-parcel data among the users of a multipurpose cadastre will depend on their use of common procedures for describing and coding property characteristics. Describing a property characteristic involves a depiction in words or a representation by a picture. One may draw sketches, take photographs, take measurements, make counts, compile lists, sort into classes, or assign ratings. The choice as to which techniques to employ depends on such factors as the nature of the characteristics being described and the purposes for which the data are being collected. Coding is the reduction or abbreviation of a description to a more manageable size through the use of letters, numbers, symbols, and fewer words. For universal use of the data, these codes must be standardized.
5.2.1 Alternatives for Classifying Land Parcels
Descriptions of land-parcel characteristics may be objective or subjective. Subjective descriptions require more intellectual effort, whereas objective descriptions are made more mechanically. Similarly, a description may be qualitative or quantitative. A house may be described as a mansion because mansions are "large" and the house in question is the largest house around—a qualitative description. Or the house may have been classified as a mansion because an assessor's cost manual specifications indicate that, among other things, mansions must have a ground-floor area equal to or greater than 3000 square feet, and the house in question has a ground-floor area of 3130 square feet—a quantitative description. There is often a close correspondence between subjective and qualitative descriptions and between objective and quantitative descriptions.
Property characteristics may be continuous, discrete, or dichotomous. A continuous characteristic or variable is one that may take on any numerical value. Building area, for example, is a continuous variable. A discrete variable, such as number of fireplaces, can take on any whole number value, usually within certain limits. The number of rooms in a dwelling ordinarily would be thought of as a discrete variable, although "half-room" counts are sometimes used. Dichotomous characteristics or variables are those having to do with the presence or absence of a condition. They are usually described by answering a yes or no question. The variables arising from the answers to such questions are often called "dummy" variables. Examples of questions that create dummy variables are, "Does this site have lake frontage?" and "Is this property defined by the Public Land Survey System?"
Some characteristics, such as construction quality and building condition, can be treated as discrete variables by developing a rating scheme or as series of dummy variables. Building condition or state of repair, for example, could be described on a scale, of, say, 1 to 10 or as poor, fair, average, or good.n Public Works Association, Chicago, Illinois (1980-1981).ents;ges occur, assessors officially are concerned with the status and value of parcels on the legally designated annual appraisal or assessment date. Thus, assessors have only a limited interest in information that is of a historical nature. $ 7.88 average cost per square mile for this statewide