Query 012: npdv:coreIntervalUOM
Query 12 mentions property npdv:coreIntervalUOM which is mentioned neither in the ontology nor in the mappings. Thus, it is always empty. As far as I understand the intention, the property specifies the units (m or ft) for the length and the union in the query duplicates the job of the pair of manual mappings. Two solutions are possible:
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the mappings perform the conversion from ft to m and all the lengths are specified in m (then the automatic mapping and Q12 will have to be changed);
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the mappings provide the number as is and then npdv:coreIntervalUOM requires a proper definition.
I'd say the first way is a better engineering practice (otherwise, the user will have to repeat the union each and every time, and the ontology+mappings was meant to alleviate the problem). On the other hand, both solution could be present in the ontology/mappings BUT using different property names.