Modeling error in objects and fields

Argues that it is often useful to analyze error in cartographic objects not by looking at models of the distortion of the object themselves, but by building models of errors in the fields of continuous variations from which many objects are actually generated. For example many maps which purport to show patches of homogeneous soil, vegetation, or land use were compiled by interpreting aerial photographs or images, combined with spot ground checks. Error models of those images may be easier to formulate and analyze. -from Editors