Finally, all 2,472 municipalities have been completely mapped as place=city/town/municipality, following the current guidelines after the discussion in https://forum.openstreetmap.org/viewtopic.php?id=73811.
However, I’ve found that current guidelines are not perfect. I used to expect that the municipality that established the community would also be the municipality that is the urban area. This is sometimes not correct. Some urban municipalities have yet to establish the community (for example, Phrao (19.368630, 99.204272), Phanom Phrai (15.678812, 104.113322)), whereas some rural municipalities comprised of many distinct villages have already established the community (for example, That Thong (https://goo.gl/maps/V2T9c3ewWKjkUUie6), Khun Thale (https://goo.gl/maps/FpBmKdBWMb9UfT9M6))). Furthermore, finding official information on whether or not each municipality has already established the community is difficult. I admit that sometimes I’m unsure if it’s established or not.
So I’d like to revise the guidelines to make them more precise and easier to follow. According to OSM wiki, a town is “an important urban centre”, thus it may be a better idea to reflect the situation on the ground rather than strict to the administration status.
As a result, I suggest the following simple guidelines:
If more than 50% of the residential area* within the municipality boundary is connected as one settlement (no other area separating it), then tag it with place=city/town
(A residential area includes anything from residential, commercial, public park, and other public urban facility, but does not include a gated private residential estate or an industrial estate. The presence of a natural obstacle, such as a river or a major highway, does not imply that the residential area is separated.)
How about this idea?