236 aPPenDiCes
Design. (1) The process of creating a map. (2) A plan of execution. (3) The appearance of a
map.
Developable surface. A surface that can be cut and flattened without distortion. The three
developable
surfaces are the cylinder, the cone, and the plane.
Direction. The location of one point in space with respect to another.
Discontinuous distribution. A distribution that does not occur everywhere in the mapped
area.
Distance-by-time cartogram. A type of cartogram that uses time instead of linear distance
as a scale.
Diverging color scheme. A color scheme used to represent increases and decreases of a vari-
able from a midpoint, such as temperatures above and below freezing or positive and
negative change.
Dorling cartogram. A value-by-area cartogram on which the enumeration areas are replaced
by
uniform geometric figures, usually circles, which are
drawn proportional to the
value represented.
Dot density map. A variation of the dot map that places dots randomly within the enumera-
tion area.
Dot map. A representation of geographic phenomena on which dots represent a specified
number of the phenomenon being mapped. The dots are placed in their area of occur-
rence within the enumeration area.
