GIS16

Uncertainty in GIS
• Uncertainty of various forms arises in the GIS representation of the real world.
– Uncertainty arises due to transformations from:
• Real World to Conceptual Model
• Conceptual Model to Representation
• Representation to Analysis
– Uncertainty includes:
• Positional inaccuracy
• Attribute inaccuracy
• Ambiguity
• Vagueness
• It is important to recognize various terms utilized for uncertainty estimation.
• For GIS analysis, uncertainty is critical in spatial representation and location.
– Granularity is a concept related to spatial imprecision.
• It means the level of spatial detail the representation of data.
• Directly tied to the selection of vector or raster object (and its resolution).
• High resolution data have high granularity.
– When granularity (low spatial resolution) is coarse:
• Objects can become indiscernable.
• Spatial imprecision is created.
Positional errors can be common in GIS data acquisition and analysis