The iObsN field in the Weather table/file is an integer assigned dynamically to the observer that ran that route that year. For each query, a number is assigned to each unique observer for a route. These numbers do not neccessarily correspond to the observer numbers assigned for another route within a query, or for the same route in another query.

Examples:
Say the following routes were run by the following observers in Washington D.C.:

sStateProv	sRoute	iYear	Observer
22	001	1992	Chip Rollins
22	001	1993	Chip Rollins
22	001	1994	Katrin Klarawitz
22	001	1995	Maude Gunterson
22	001	1996	Sid Froege
22	001	1997	Katrin Klarawitz
22	002	1992	Jim Shauer
22	002	1993	Jim Shauer
22	002	1994	Diana Dobson
22	002	1995	Diana Dobson
22	002	1996	Kenneth Partridge
22	002	1997	Chip Rollins
22	003	1992	Kenneth Partridge
22	003	1993	Brad Peterson
22	003	1994	Brad Peterson
22	003	1996	Kenneth Partridge
22	003	1997	Captain Wei

Query: StateProv = 22 Route in ( '001') Year >= 1966 Year <= 1997
Weather Subset

sStateProv	sRoute	iYear	iObsN
22	001	1992	1
22	001	1993	1
22	001	1994	2
22	001	1995	3
22	001	1996	4
22	001	1997	2

Query: StateProv = 22 Route in ( '001') Year >= 1995 Year <= 1997
Weather Subset

sStateProv	sRoute	iYear	iObsN
22	001	1995	1
22	001	1996	2
22	001	1997	3

Query: StateProv = 22 Year >= 1967 Year <= 1997
Weather Subset

sStateProv	sRoute	iYear	iObsN
22	001	1992	1
22	001	1993	1
22	001	1994	2
22	001	1995	3
22	001	1996	4
22	001	1997	2
22	002	1992	1
22	002	1993	1
22	002	1994	2
22	002	1995	2
22	002	1996	3
22	002	1997	4
22	003	1992	1
22	003	1993	2
22	003	1994	2
22	003	1996	1
22	003	1997	3