27. The non-transitory computer-readable medium of claim 21 , wherein: determining at least one local concept comprises determining a score for each local concept; and the local concept with the highest score in each region comprises a most relevant local concept for that region.
27. The non-transitory computer-readable medium of claim 21 , wherein: determining at least one local concept comprises determining a score for each local concept; and the local concept with the highest score in each region comprises a most relevant local concept for that region. 28. The non-transitory computer-readable medium of claim 27 , wherein identifying unrelated concepts comprises: determining a revised score for each local concept; determining said ranked global list of all local concepts based on the revised scores; removing local concepts whose combined revised score contributes less than a predetermined amount of a total score of the global list to produce a resulting list; identifying unrelated regions without a most relevant local concept on the resulting list; and removing local concepts expressed in the unrelated regions from the resulting list to produce a list of relevant concepts.