[postgis-users] Re: Status of geocoding functions in PostGIS?

Putler, Dan Dan.Putler at sauder.ubc.ca
Fri Mar 31 08:24:14 PST 2006


Hi Steve,

At the moment we are working on two things. First, modifying PAGC so  
that we can use it to augment road network files, particularly the  
new StatsCan road network. The data is released province by province,  
but their are no local identifiers. So common addresses like 821 10th  
street get multiple perfect matches. The second thing we are doing is  
allowing people to edit the address ranges (temporarily) on the fly.  
Often the address range information is incomplete or simply missing  
for some streets in all the road network files we have worked with.  
So a user will often find an address range that is very close, but  
not exact. PAGC will allow them to alter the address range of the  
"close" road segment, and geocode relative to the altered segment's  
address range. The users changes will be written to a separate file,  
with the idea that we might be able to collaboratively filter users  
proposed changes to update the underlying road layer.

Right now PAGC is a command line tool (and is about as complicated to  
use as something like ogr2ogr), and a bit more oriented to doing  
batch geocoding. Converting it to a library is likely to be next  
after we get the address range editing capability to a reasonable  
level, as well as figuring out what we need to do to allow PAGC to be  
used in web applications. Up to this point we have not thought about  
creating a library oriented towards implementing a Postgres stored  
procedure. It does make a lot of sense. I will say we are likely to  
need a hand or two (or three) to help us do that. Walter Sinclair is  
the lead developer on PAGC itself, while I handle testing and data  
issues. Neither of us has much (read "no") experience with Postgres  
internals. Walter's underlying geocoding engine is really excellent  
(much better that the commercial  products I have used), but certain  
very worthwhile extensions we are going to need help implementing. If  
you, or anyone else on this list, is interested in helping out the  
PAGC project, please get a hold of us at pagcmail at google.com.

Dan

On 31-Mar-06, at 4:54 AM, Stephen Woodbridge wrote:

> Hi Dan,
>
> Have you guys made any progress in refactoring PAGC to be a  
> library. Since I see you on this list also have you thought about  
> building a library that can be used to implement a Postgres stored  
> procedure using PAGC?
>
> PAGC is very cool with lots of nice technology but it is a little  
> difficult to get ones arms around it in its current state :), OK  
> for me anyway.
>
> Very nice work,
>   -Steve
>
> Putler, Dan wrote:
>> Hi Paul,
>> You might want to look at the PAGC project (www.pagcgeo.org),  
>> which I'm a member of. PAGC is written in C and works with  
>> shapefiles. The intention goal is also to make PAGC extensible so  
>> it can be used for geocoding postal addresses in a number of  
>> countries. Currently it works out of the box with TIGER/Line data  
>> and the new Statistics Canada public road network file (that  
>> actually needs to be augmented with additional information until  
>> it is really useful). The problem we have run into is that few  
>> governments release address ranged road network files (we only  
>> know that the US and Canada do, and all the EU countries don't),  
>> so we haven't been able to work with anything other than US and  
>> Canadian data. It sounds like you might benefit from our code  
>> base, and there could be room for collaboration at some point.
>> Dan
>> On 30-Mar-06, at 9:48 PM, Paul Scott wrote:
>>  > On Fri, 2006-03-31 at 04:48 +0000, Mark Thomas wrote:
>>  >>>
>>  >>> Alex Smith wrote:
>>  >>>> Did some searching of the archives and found this article   
>> >>>> stating that a
>>  >>>> geocoder for PostGIS is in the works (see
>>  >>>>
>>  >> http://postgis.refractions.net/pipermail/postgis-users/2004-
>>  >> September/005762.html).
>>  >>
>>  >
>>  > If you would like to contribute to a project that is based on   
>> > creating a
>>  > set of global geocoders, take a look at
>>  > http://avoir.uwc.ac.za/projects/geocoder/
>>  >
>>  > This project is attempting to collect geocoders that will work for
>>  > almost anywhere that you may need. If you would like to join the
>>  > project, please just let me know!
>>  >
>>  > --Paul
>>  >
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