Sketch-based Spatial Reasoning in Geologic Interpretation

Geologic interpretation is the process of determining a sequence of geological events that could have caused a particular geologic formation. This paper describes a model for geologic interpretation of sketches, which are collected and represented with our open-domain sketch understanding system, CogSketch. The spatial relations that CogSketch computes are combined with a domain theory for geology to support state-to-state inference, which allows the system to make inferences about geological processes that may have occurred as well as spatial features of the previous geologic state. State-to-state inference involves three steps. First, spatial relations are used with proposal rules to infer the set of all geological processes that may have caused the geologic state depicted in the sketch. Second, spatial and temporal constraints are applied to refine this list of candidate processes. Third, candidate processes are used to infer facts about the prior state which are tested through verification rules. The model has been successfully tested on 7 sketches which involve the six basic physical principles geologists use for determining the relative age of rocks. These results also highlight several opportunities for improvement.