[postgis-users] Newbie Duplicates Question

Paragon Corporation lr at pcorp.us
Wed Sep 19 16:10:19 PDT 2012


If you are looking for disk space, just delete the addrfeat tables.  They
are a denormalized join of addr / edges and feat and we aren't using them.


I had planned to use that instead of edges but after much thinking, decided
it really didn't provide any benefit and just took up a lot of disk space.
I think the 2.1 loads them, but I'm planning to disable it.
You can turn of loading of that table by setting the
tiger.loader_lookuptables load column to FALSE for addrfeat.


As far as addr tables, having duplicate tlids is expected because each addr
represents a particular side of a street of a tlid and in some rare cases
you may even end up with more than 2 for some really weird roads.


That table is pretty light relative to others anyway so doesn't save you
much.

Tlid should be unique in edges, though I think it may be duplicated at
county boundaries (it was in 2010 data as I recall, though I think in my
2011 MA data they were unique).


Hope that helps,
Regina
http://www.postgis.us

 

-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Michael
Papet
Sent: Wednesday, September 19, 2012 3:17 PM
To: postgis-users at postgis.refractions.net
Subject: [postgis-users] Newbie Duplicates Question

I am slowly assembling a postgis 2.1.0SVN database with Tiger2011 data using
the loader scripts. I've re-run the scripts for a state a couple of times
because I made some newbie mistakes.  

Disk space is an issue for me right now.  Is there a column I can check in
the state tables for duplicate rows? For example, SELECT tlid,
COUNT(tlid) AS NumOccurrences
FROM tiger_data.al_addr
GROUP BY tlid
HAVING ( COUNT(tlid) > 1 )

finds many duplicates, but I don't know enough about the column to know if
it's supposed to be unique. Column arid far fewer finds duplicates, but
again, I don't know if that makes them true duplicates.

Thanks for your patience,

mpapet
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