A formatting object according to the present invention conveys information to the reader of a document (such as a table or chart) by associating visual attributes (such as color, fill type, border width, line width, line style, font size, marker size and marker type) to characters or markers within the document. The formatting object may be used to emphasize data within a table or a chart by modifying the structural visual attributes of characters or markers within the table or chart according to pre-defined criteria. Similarly, the formatting object may be used to increase information density within a table or chart, and to elegantly represent the relationships between four or more interrelated variables in a two-dimensional chart. The formatting object accomplishes this by defining at least one format map that comprises one or more mapping segments. Each mapping segment includes a beginning boundary value, an ending boundary value, at least one beginning visual attribute corresponding to the beginning boundary value, and at least one ending visual attribute corresponding to the ending boundary value. The formatting object uses the information within the format maps, in combination with interpolation techniques, to determine one or more visual attributes that correspond to data points falling within the various mapping segments. The formatting object then expresses the data values by applying the appropriate visual attribute to a visual object displayed on a computer screen.