Term

Definition
directly proportional scaling of area or volume of symbols to data values 


Term

Definition
in psychological theory, a neutral reference point on which perceived judgments are based; affected by the perceptual anchors from which judgments are made 


Term

Definition
the size of the visual anchor affects the estimates of magnitude of an unknown symbol; the contrast effect causes estimation to be away from the anchor, and the assimilation effect causes judments to be toward the anchor 


Term
Apparent Magnitude Scaling 

Definition
scaling of proportional symbols that incorporates correction factors to compensate for the normal understimation of a symbol's area or volume 


Term

Definition
in the literature and classic sense, refers to any of the scaled point symbol mapping schemes; with GIS implemntation impolies range grading using ordinally scaled symbols 


Term
proportional Midpoint Range Grading 

Definition
variation of the range grading in which symbols are in proportion to the midpoint of a class range 


Term
Proportional Point Symbol Mapping 

Definition
type of quantitative thematic map in which point data are represented by a symbol whose size varies with the data values; areal data assumed to be aggregated at points may also be represented by proportional point symbols 


Term

Definition
traditional cartography and modern GIS term that describes symbols that are in true proportion to their attribute data; in GIS usually associated with absolute scaling, and in some GIS software, apparent magnitude scaling 


Term

Definition
the mathematical expression that describes the relationship between stimulus and response; gener for is RK*S where R is respons, S is stimuls and K is a constant



Term

Definition
a symbol represents a range of data values; differently sized symbols are chosen for differentiablity for each of several ranges in the series of values being mapped; larger symbols indicate more of a quantity but are not in true proportion to the data tey represent 


Term

Definition
expressing the same variable by more than one visual variable; in proportional symbol mapping, the symbol's fill will change in saturation and/or value in proportion to the data that scale the symbol's size; larger symbols have a lighter or less saturated fill 


Term

Definition
too much information in a symbol, so that readers have difficulty making assessments about the quantitative nature of the data. 


Term
Threedimensional point symbol 

Definition
any point smbol made to appear three dimensional, such as a sphere or cube 

