Talk:LITNUM

jens 11:24, 8 November 2010 (UTC) that is another open topic.
Where to put the national number?
Is that correct to separate the number into 3 pieces? Wouldn't be the letter code and one number (real with 4 decimal) not sufficient?

jens 09:33, 26 November 2010 (UTC) next point. Having sector lights we should assign the light number to the master (in S57 term) perhaps the building where the light is located. The different light sectors itself are the slaves.

jens 17:23, 27 November 2010 (UTC) That causes necessarily the question whether the light number is a candidate to become an associated information object and we have to reconstruct the information.

raphael 02:50, 29 November 2010 (UTC): How are the separate components given by the sub-attributes expected to be used?

jens 08:07, 29 November 2010 (UTC) good point Raphael. I assume that is because the UKHO has uses separate data fields to built their international light number. But I'm not 100% sure that that is correct. We should wait for David to uncover the mystery.

DavidAcland 14:19, 2 December 2010 (UTC) : I cannot remember the whole story but I think we came up with this format at Brest. UKHO currently stores this as a string in one field. There is a bit of input checking: There must be an initial letter; there cannot be more than 5 numbers before the decimal point; and there cannot be more than 4 after.

raphael 04:27, 3 December 2010 (UTC): S-100 provides the "textPattern" constraint, which can express rules like these for a simple attribute LITNUM of type String.

Constraint:
textPattern: [A-Z]\s\d{1,5}\.\d{1,4}
to express the rule that there must be an initial upper-case letter, followed by a space, then 1-5 digits, then a ".", then 1-4 digits.

jens 06:39, 3 December 2010 (UTC) Thanks Raphael, we can amend the attribute according to your advice. That makes the model simpler. David, what do you think? Shall I or you do the tighten work?

jens 06:40, 3 December 2010 (UTC) Remains the problem where to add the attribute? See my posts 09:33, 26 November 2010 and 17:23, 27 November 2010 (UTC)

raphael 09:06, 3 December 2010 (UTC): LITNUM can be bound as an attribute of the master, or as an attribute of an association type or geographic feature object which collects the different LIGHTS objects? (Though S-100 Appendix 2A-A suggests that there would one LIGHTS object with sectors described by a complex attribute, if so this problem should not arise.)