Re: quantity database

• To: visad-list@xxxxxxxxxxxxx
• Subject: Re: quantity database
• From: Steve Emmerson <steve@xxxxxxxxxxxxxxxx>
• Date: Tue, 14 Apr 1998 10:40:32 -0600

Bill,

>Date: Tue, 14 Apr 1998 10:46 CST 
>From: "William L. Hibbard" <WHIBBARD@xxxxxxxxxxxxx>
>To: visad-list@xxxxxxxxxxxxx
>Subject: Re: quantity database 

In the above message, you wrote:

> There should probably be system default values that users can
> override.  Perhaps discipline-specific databases that can be
> merged in multi-discipline applications.
>  
> There should be no problem putting it into the core VisAD package,
> possibly with discipline-specific databases in discipline-specific
> subpackages.

Actually, support for discipline-specific quantities might be
unnecessary.  There are far fewer "generic" quantities than there are
units for such quantities -- and we already support almost every unit in
a single package.  By "generic" quantities I mean things like "speed"
as opposed to "wind speed" (which *is* discipline specific).

Do you think qualifiers like "wind" will be necessary?  I'm not sure.
Instead, I think we'll need a way to map a user's "wind speed" variable
to the quantity "speed" (and its associated MathType, default Unit, and
default Set).  I'll see what I can do to support such a mapping.

--------
Steve Emmerson   <http://www.unidata.ucar.edu>