Chapter 6

From AMLCartography
Jump to: navigation, search

For the generation of graduated symbol maps (which should be used for discrete, abruptly changing, ordinal to ratio area data), ARC/INFO provides two commands that allow rapid generation of these maps: SPOTSIZE and POLYGONSPOT. SPOTSIZE controls the scaling of data to circle size, and POLYGONSPOT does the plotting of the circles. A second method of graduated symbol mapping is cartograms. These maps scale individual polygons on the basis of a data value. Cartogram creation requires interactive map composition, both for the scaling of polygons and the repositioning of scaled polygons.