There are several techniques available in ARC/INFO for the production of choropleth maps (for area data that is continuous, and changes abruptly at polygon borders). These techniques include hue, texture, orientation and shape for nominal data, and size for ordinal to ratio data. As with the other monovariate sections, the AML's start off simply in order to build a base for bi- and multivariate mapping. Also these techniques tend to make use of lookup tables, which should be generated prior to executing the display AML's.
ARC/INFO provides a default set of area fills in the shadeset file, PLOTTER.SHD; there are several other available shadesets: CARTO.SHD, COLOR.SHD and COLORNAMES.SHD. These are displayed in the Map Display and Query guide's Appendix C, and the ability to create new symbols sets is discussed in chapter three of Map Display and Query.