In Henan searching for my ancestors, why are some village names found in county records but not on maps?

When searching for my ancestors in Henan, 90% of people overlook the 'Migration Landmark Annotation Method' in genealogy, a crucial clue.

Luoyang Water Banquet Full Menu Guide: The regional differences hidden within - 'Peony Swallow Dish' in old town restaurants and new district restaurants are completely different dishes

Why are those unwritten details in the Bao Gong Cultural Scenic Area rarely mentioned even by tour guides?