[postgis-users] geo-coding question

Stephen Woodbridge woodbri at swoodbridge.com
Wed Jun 27 11:03:47 PDT 2007


Lee,

Another question, can you talk about how you are doing your livesearch? 
Is this doing a fulltext search, are you parsing the incoming address 
string and generating dynamic queries?

For example: "543 Hough St, Illinois" does not filter non Illinois 
addresses. Are you only searching for the street name? What happens when 
you search for something common like "101 main st" It seems you only 
return 12 results, What if you put them in a grid as permalinks, and 
then you could page through the results like 12 at a time to see more.

Anyway, just some ideas. I like it.

-Steve


Lee Keel wrote:
>> -----Original Message-----
>> From: postgis-users-bounces at postgis.refractions.net [mailto:postgis-users-
>> bounces at postgis.refractions.net] On Behalf Of Stephen Woodbridge
>> Sent: Wednesday, June 27, 2007 10:39 AM
>> To: PostGIS Users Discussion
>> Subject: Re: [postgis-users] geo-coding question
>>
>> Lee,
>>
>> The refractions team work a geocoder in pgsql procedures that assumes
>> some Tiger data has been loaded. There are occasional requests for help
>> on loading data, but I'm not sure if there is an explicit well defined
>> procedure for that. I think the PostGIS geocoder was written as a proof
>> of concept and I am not aware of anyone using it in a production
>> environment. OracleSpatial geocoder is a mature production quality
>> geocoder, but it expects Navteq data, or data that can get munged into
>> Navteq format.
>>
>> The difficult part of geocoding is handling address standardization and
>> handling fuzzy searching. Once you can standardize the addresses the
>> query part is trivial in comparison. Much of the Oracle's geocoder is
>> written in Java in their application server.
>>
>> -Steve
>>
>>
> 
> Steve,
> 
> You are absolutely correct that the most difficult part of the geocoding
> process is the address parsing.  We have spent many hours refining our
> parser to work as much as possible and we have some more to go.
> 
> The website that I sent before is in a "production" environment.  We are
> using postgres plpgsql functions to do our geocoding against the full US
> Tiger 2006 2nd Ed dataset.  I agree that there is probably not an explicit
> well defined procedure for loading the Tiger data.  We currently are
> converting the data to shapefiles, then importing the shapefiles with a
> little messaging done after that.  Of course that will change in the next
> Tiger release when the data is available in shapefiles already.  But even
> then, it is obvious that any geocoder that is using tables for address
> parsing will be expecting certain tables to exist with certain columns.  I
> don't know any way around that part of it. 
> 
> We have gotten around a lot of the need for fuzzystring matching by doing
> the live search.  So the user can quickly and easily see their selection
> within the dropdown as they are typing.  We have been working on a
> fuzzystring match side for another page that has a different purpose, but
> that is probably round 2.
> 
> I know the OracleSpatial geocoder is a LOT more mature than what we have,
> but what we have is a pretty good starting point.  We definitely have some
> enhancements left to be made, but I thought this live geocoding search is a
> pretty good show case for the speed of postgres\postgis against a roads
> table of more than 39 million rows.
> 
> Regards,
> Lee Keel
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