MathModel question

I am debating between using the following MathModels for my data:

((lat,lon) -> (val1, val2, ... , elevation) )

or

( ((lat, lon) -> (val1, val2, ...)) , ((lat, lon) -> elevation))

where (val1, val2...) are some data value such as temperature or
precipitation.

The reason I am having this debate is that I frequently will need to
perform operations on just the val1 and val2 without changing
elevation.  In the first case, this necessitates doing extract's and
combine's each time I perform an op, whereas in the second case it is
only necessary to do a getComponent() on the Tuple, followed by
constructing a new Tuple after performing the operation(s).  It seems
clear that the second choice would be more efficient, but i'm still
inclined to go with the first, as it's more "standard" insofar as file
storage goes.

So, I guess my question is, in the long run, am i going to take a big
hit, efficiency-wise, if i go with the first MathModel and do all those
extract's and combine's, or would a comparable number of those
operations be performed anyway by the code that performs the ops ?

john


-- 
John Brecht
SRI International
Center for Technology in Learning
333 Ravenswood Avenue
Menlo Park, CA  94025
650-859-2325 (voice)
650-859-3673 (fax)
john.brecht@xxxxxxx
begin:vcard 
n:Brecht;John
tel;home:(415)260-7898
tel;work:(650)859-2325
x-mozilla-html:TRUE
url:http://jbrecht.sri.com/john/
org:SRI International;Center for Technology in Learning
version:2.1
email;internet:john.brecht@xxxxxxx
title:Software Engineer
adr;quoted-printable:;;333 Ravenswood=0D=0ABN 261=0D=0A;Menlo Park;CA;94025;USA
fn:John Brecht
end:vcard