[OSM-dev] Anyone with a speedy gazetteer

[Milo van der Linden]

I strongly suggest that you read the postgresql text search[1] chapter 
in depth. You will find that a lot of textual and multilingual 
confusions can be solved with that function set. the name "text search" 
is by far too simple for what it covers...

Regards,

Milo

[1] http://www.postgresql.org/docs/8.3/static/textsearch.html


David Earl wrote:
> On 12/01/2009 13:51, Milo van der Linden wrote:
>> As Tom Hughes suggested earlier on; perhaps it would be smart to use 
>> postgres,
>>
>> especially since somany postgres/postgis instances are lying around 
>> for the mapnik servers that the openstreetmap community uses. My 
>> guess would be that a lot of people would be able to support you:
>>
>> http://www.postgresql.org/docs/8.3/static/textsearch.html
>> http://www.postgresql.org/docs/8.3/static/fuzzystrmatch.html
>>
>> The textsearch module for postgresql handles records in the database 
>> as "documents"; giving you a broad variety of search functions.
>>
>> Perhaps this is the right compromis between a real search engine and 
>> searching records in a database.
>>
>> Regarding the near by; this would mainly mean "select this and that 
>> where searchterm="bla" and distance(the_geom, yourlocation) < x.
>>
>> The last query needs an extremely good design since distance 
>> functions perform somewhat problematic..
>
> That function the starting point for writing namefinder in the first 
> place.
>
> But please be clear - this isn't just a simple text searching 
> application. It needs to cope with variations in language and 
> abbreviations and so on, and it has to cope with large numbers of 
> duplicate names, some of which are not the same object as another of 
> the same name, and some are; and as you say, the proximity - which 
> isn't just in the unqualified searches - the results try to give you 
> not just a  hit ("1. Main Street, 2. "Main Street", 3. "Main Street" 
> ... is not helpful) but with a context so you know which is the one 
> you are really looking for. This is true even of place names (see the 
> discussions re Paris we were having a month ago).
>
> If we were only searching the names in the planet file or some other 
> plain text, life would be simple. But it is a great deal more 
> complicated than that to produce useful, contextual results. And I'd 
> be the first to agree that it isn't there yet.
>
> David
>
>