Monday, July 13, 2009

Geocodes for municipalities - my proposal

Thai standard TIS 1099:2548 includes some codes for municipalities, and in some Excel sheets I found more of the same kind, giving the municipalities a code at district level starting from 99 counting downwards. However the scheme, apparently originating from DOPA, used to create those codes cannot be continued anymore as now we have so many new municipalities, soon reaching 100 in Nakhon Ratchasima and already now interfering with the district codes.

The second geocode system comes from DOLA, and includes the subdistrict administrative organizations (TAO) and provincial administrative organizations (PAO) as well. However this one is incompatible with the DOPA system, and has some other flaws I already mentioned while writing about it before.

Though I doubt this will ever be read by anyone who is responsible for creating these coding schemes and taking care of future versions for that standard, let alone get adopted, I want to present my own idea on how to create codes for the local government units which fit into the existing DOPA system, like the DOLA system covers all entities and includes no new arbitrary selected codes.
  • For the municipalities existing in 2000 - that is both the really old municipalities as well as the sanitary districts upgraded in 1999 - continue to use the scheme as already defined in TIS 1099, i.e. give these entities a code at district level counting from 99 downwards. For example in Surat Thani this would mean the codes 8499 down to 8479 would be used.

  • For the TAO, use a code based on the corresponding subdistrict and adding 50 to make sure no code is used twice. 50 also leaves enough space for newly created subdistricts (though it seems there won't be any new ones anymore), or those cases where already rather high subdistrict codes are used from district which were split recently. Also some obscure old codes with subdistrict numbers in the range 90 to 99 won't get reused - I don't know what these codes are about, but there are a few in the ccaatt list from DOPA.
    In case the TAO gets upgraded to a municipality, the code is not changed. For example subdistrict municipality Wat Pradu in Surat Thani would get the 840153, as the corresponding subdistrict has the code 840103.
  • If there really needs to be a code for the PAO as well, this could get the code 0099, the Surat Thani PAO then would be 840099. Thus it makes clear it's not a district nor a normal municipality.
The only disadvantage of this system would be the fact that those municipalities existing before 2000 would get a code in a different system than those created afterward. However I think this is an acceptable trade-off in order to keep the already published codes for municipalities.

Once defined like this, the subdivisions of the municipalites would fit into it easily as well. Just like the villages (muban), the chumchon would use the digits 7 and 8 regardless whether the municipality has a code with four or six digits. Quite the contrary, this would have an advantage, as it seems that a few of the largest municipalities have an addition subdivision called Kwaeng, so these then could use the digits 5 and 6. For example, the first chumchon in the first Kwaeng of Chiang Mai would be 50990101, while the first chumchon of Surat Thani gets 84990001.

Any comments? Anyone willing to translate it to Thai and forward to the persons responsible?

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