Answer
The output associated with a 0.5 quantile map corresponds to the median estimation of the value at each unsampled location. The 0.75 quantile represents values that are overestimated and correspond approximately to a 25% probability that the value at the unsampled location exceeds this estimation. Quantile maps can be used in the decision making process when misclassification is undesirable since it is better to overestimate values at unsampled locations than to not identify locations with increased values.