John, Steve, (et al)
Another, simpler, example is the case where you have a scalar time 
series (per my example).  If you determine that, for synchronization 
purposes, gaps in the telemetry should be preserved in the variables, 
then you may have instances in which there is no time data.  Unless you 
decide to synthesize time values, you need to have fill values.
Jim
--
Jim Biard
Government Contractor, STG Inc.
Remote Sensing and Applications Division (RSAD)
National Climatic Data Center
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