 What is it? Vagueness Measurement errors Boundary identification  Why is it important to quantify? Critical applications of GIS Military, Emergency Services, Demographics

 Applications in medical geography ◦ Mapping of cancer clusters ◦ Cholera outbreak  Methodology to model spatial correlation among rates across geographic measures and risk estimates

 Objects and their attributes can be uncertain  Leads to movement of an object and related objects

 Representations of motion plans ◦ Measurement of time & location  Requires continuous re-evaluation ◦ Measurement of time, location and velocity  Can be predictive, but allows deviation ◦ Measurement of start location, end location and start time  Small disturbance in one location may affect entire path

 Relative Positional Accuracy  Absolute Positional Accuracy  Which is more useful in application?  Shifting geometries to achieve ◦ Shifting by Interpretation ◦ Geometric shifting ◦ Rule Based Shifting