[postgis-users] SRID and unprojected (Census) data

[Lee Hachadoorian]

Can someone please give me some ideas, or pointers to where this 
question is answered elsewhere, on how to handle unprojected geographic 
data in PostGIS?  Would I just create the table with SRID = -1?  The US 
Census makes several cartographic boundary files available using the 
NAD83 datum, but unprojected (with just lat/long coordinates for each 
point or polygon).  I looked through spatial_ref_sys, and there are over 
500 NAD83 reference systems, but it appears that they are all projected 
(UTM, state plane, whatever).

Thanks in advance,
Lee Hachadoorian
PhD Student, Geography
Program in Earth & Environmental Sciences
CUNY Graduate Center