GG251 Lecture Notes - Iqvia, Arcmap
Document Summary
Land uses are nominal categories, hence the palette with a discrete colour different than its neighbours is acceptable (qualitative palette) Quintiles: data classification technique used to determines using the number of features to be mapped. Refers to the size of symbol in relation to the data. Two kinds: graduated and proportional: graduated symbols. Range grading: single symbol size to represent a range of data values. Three decisions: number of classes, method of classification: same as choropleth, symbol sizes: arcmap default provides a graduated range based on equal increments of point size data, proportional symbols. Mathematical: function applied to attribute vale, most commonly square root, to determine the diameter of the symbol. Perceptual: numerous empirical studies have shown perceived size of proportional symbols does not correspond to mathematical size of larger symbols: arcmap called appearance compensation (flannery)
