| This research investigates how the inclusion of attribute certainty in map displays influences GIS modeling and spatial decision support. The goal is to establish empirical evidence documenting graphical guidelines that can be incorporated as GIS system defaults for mapping attribute certainty. Value, texture and saturation appear as visual variables associated with the depiction of attribute accuracy. These three variables, in addition to the level of map detail, are explored in this research.;A hypermedia document has been developed to simulate decision makers' use of certainty information for two locational siting tasks: the siting of a park and the siting of an airport. The experiment has been designed to observe the time, correctness and confidence of both siting decisions. The experiment then determines how variations in symbolizing attribute certainty are affected by the three variables time, correctness and confidence. A third goal focuses on whether the difficulty of the task affects the decision.;On a theoretical level, this research uncovers new information about assimilating data quality information into spatial decision support. On a practical level, it establishes symbolization schemes for representing attribute certainty on thematic maps. Once established empirically, these guidelines should be incorporated as GIS graphical defaults in anticipation of digital datasets that include data quality information. This research continues the trend in cartographic research of re-establishing empirical testing as a paradigm for eliciting and formalizing cartographic (design) knowledge. |
