Unique Cave Identifiers

[nschorgh]

An international cave id would uniquely identify each cave in the world, but such an identifier has not yet been established by the speleology community. As more speleological databases become available online, it will be urgently needed to identify duplicate entries. Absent an internationally agreed convention, CaveXML effectively uses the following international identifier:

2-letter ISO country code + optional 3-letter organization code + published national cave registry number

Examples:
AU-ASF-4U-30 Bayliss Cave, ASF = Australian Speleological Federation
AT-1511/24 Eisriesenwelt in Austria, uses cadastral number and no organization code

• UISIC proposes to use the ISO two-letter code of the country of the organization that created the identifier. Here it is proposed to instead base it on the country the cave is located in. (In CaveXML the two-letter code can be generated from the <country-name> field, and the remaining national cave identifier is stored in the element <cave-id>.)

• The optional 3-letter organization code is recommended by the UISIC. One issue is how to rigorously separate the 3-letter organization code from what could be the beginning of the national cave registry number. For example, in Italy the national cave identifier LOLC1739 refers to a cave in the region of Lombardy, province of Lecco, number 1739, but could incorrectly be parsed as organization code LOL and cave number C1739. Introducing a separate tag for the organization id seems onerous. Requiring a dash after a 3-letter organization code would reduce the probability of confusion, but not eliminate it entirely. Any thoughts?

• Restricting cave identifiers to ASCII characters, or even a subset of ASCII characters, facilitates portability. CaveXML allows ASCII character codes 33 to 126, which are all the printable ASCII characters except for space. It is worthwhile discussing which special ASCII characters should be considered significant in the cave identifier. For example, LO/LC should be considered to be equivalent to LOLC, but if slashes are ignored, then 1511/24 is equivalent to 151124 and indistinguishable from 151/124. That might even be okay, because cadastral numbers within a region should all have the same number of digits. Further discussion is needed. There must be an unambiguous mechanism to match cave identifiers.

• It is not necessary to place a length limit on the identifier, but it is also clear that an identifier should be concise. The longest id in the CaveXML database so far is RU-5536/16010-11, which has 16 characters if country code and the first dash are counted, or 13 characters without them.

• One cave can have more than one cave id. That seems almost inevitable. For example, a national and a regional organization may have assigned different ids to the same cave. Also, over long periods country boundaries and organizations can change. (CaveXML should probably be augmented with an element <previous-country-name>, but that is a topic for a separate discussion.)

Finally, here are examples of record identifiers from the current database that illustrate patterns used.
AT-1511/24
AU-ASF-4U-30
CH-VD-257
CN-N44E128C-005
ES-LP/EP-6
IT-SICT-1117
KE-NGR-415563
ME-03149
RU-5236/15758-1
US-NSS-611-1 (organization: National Speleological Survey)
UZ-T21

UISIC = Informatics Commission of the International Speleological Union
UISIC Cave ID field CA227