The Dangers of Cannibalizing Data Models

[Douglas Tody]

On Wed, 23 May 2012, Rob Seaman wrote:

> A couple of comments in support of Arnold's self-consistent world view:
>
>> I have always objected to the practice of cherry-picking components from STC, since it destroys the integrity of the model: there is no guarantee that the metadata are either self-consistent or complete anymore.  And Utypes are a form of doing this.

>> Pierre le Sidaner complained that in ObsTap he could not characterize time appropriately.  Of course not: it contains a Time Scale, but adding a Time Reference Position was deemed not to be necessary.

Heaven forbid if should allow applications (ObsTAP for example) to
define what is required for their application, rather than someone who
defines a complex, general data model that could be used for anything.

In the case of ObsTAP we have an application of the general data models
which is used for data discovery, global data discovery in particular.
Precision timing is not required for this purpose.  ObsTAP merely
determines that a dataset (out of the potentially billions out there)
contains data within some specified time range.  If a client analysis
application requires precision timing it will find more precise time
calibration data by using other interfaces to examine in more detail the
datasets discovered by ObsTAP.

 	- Doug