(!) skip null date info

[VladimirAlexiev]

NPG Object 622 doesn't have date info (dated=NULL, start=0, end=0).
http://data.americanartcollaborative.org/page/npg/object/622/production/timespan emits such values, which are non-sensical (also, year 0 is invalid).

You should skip the Time-Span node altogether and all incoming and outgoing props.

[bsnikhila]

Fixed.

[VladimirAlexiev]

This query still returns 13k null timespans http://yasgui.org/short/rkpH8KDnl

PREFIX crm: <http://www.cidoc-crm.org/cidoc-crm/>
select * {
  ?x a crm:E52_Time-Span.
  filter not exists {?x crm:P82a_begin_of_the_begin ?y}
  filter not exists {?x crm:P82_at_some_time_within ?y}
}

Working from the top, I see: Autry makers, one Autry object, NMWA objects...

[VladimirAlexiev]

NMWA have rdfs:label, eg "c. 1935".
@workergnome is that enough for you, or you'd like a structured date?

[workergnome]

I would always prefer a xsd:date over a string, preferably a BOTB EOTE pair as you suggested in american-art/ccma#18.