[OSM-talk] Improved name searches

[SteveC]

all ghood suggestions, would you mind adding them to this ticket?

http://trac.openstreetmap.org/ticket/281

* @ 22/11/06 05:14:27 PM david at frankieandshadow.com wrote:
> If I search for "Elizabeth Way" (to pick a random local example) in the map
> search at http://www.openstreetmap.org/, I get well over 1,000 hits. The one
> I'm looking for is number 336 (and also 337-340, because it is split into
> multiple pieces), preceded by loads of Elizabeth Streets. This can only get
> worse and is already impractical.
> 
> How about the following suggestions to improve the intelligence of the
> search.
> 
> Firstly, using already present data:
> 
> If I ask for "Elizabeth Way, Cambridge" (or put the Cambridge bit in a
> separate box, though the comma seems quite natural):
> 
> (i) look up nodes with "place" tags with "place_name=Cambridge" (or
> "name=Cambridge"),
> 
> (ii) for each search result calculate the average latitude and longitude
> from its nodes if it is a linear feature,
> 
> (iii) sort the results by the minimum of the (great circle) distances
> between that average point and each of the matched places (or possibly a
> simpler calculation, use 2D geometry - linear distances - first discarding
> anything not "nearby" - e.g. longitudes or latitudes differ by more than 3
> degrees).
> 
> (iv) in each displayed result put something like "2.4km from Cambridge,
> Cambridgeshire, England, UK" (the latter parts from the is_in tag for the
> place, if there is one) according to which was the smallest distance, then
> you can immediately see which is the likely one you were searching for *in
> context*
> 
> Furthermore, I like the way the search is fairly loose, but can more precise
> matches be put near the front of the list (I think this should take
> precedence over the above ordering), so if I ask for Elizabeth Way, I get
> matches for both words before matches for just the first.
> 
> To be even better (probably essential) look for special cases among the
> search terms so that Rd and Road, St and Street, Ave and Avenue, StraBe and
> Strasse and Str (if that's the correct German abbreviation) etc are treated
> as equivalent (so if I look up "Elizabeth St", it would match "Elizabeth
> Street" in the database and vice-versa). This can't just be the last word as
> some languages (French) put the name last ("Avenue Champs Elysee", "Rue de
> 14 Juillet")
> 
> Secondly, do we want to advocate adding is_in on Ways? This could make the
> search much beter still:
> 
> So if I were to tag Ways as
>   "is_in=Cambridge" (*) or
>   "is_in=Cambridge,Cambridgeshire,England,UK"
> for example, then:
> 
> (a) results could be labelled with the is_in tag, e.g. if I search for
> "Elizabeth Way" I see (among others) something like
>   Elizabeth Way (k:name) (in Cambridge, Cambridgeshire, England, UK)
>   ...
> 
> (b) searches such as "Elizabeth Way, Cambridge" can be much more precise
> than my heuristic sort suggestion, narrowing the search to those results
> which have is_in tags matching Cambridge (i.e. "is_in LIKE '%Cambridge%'" in
> sql terms, though I'm sure it wouldn't be quite so simple).
> 
> Obviously as in the heuristic sort, (b) would pick up all instances of
> Cambridge, e.g. Cambridge in Massachusetts USA and Cambridge in
> Gloucestershire UK as well as Cambridge in Cambridgeshire UK. The qualifier
> could be in a different field if necessary, but the comma seems a pretty
> natural way to do this.
> 
> If I only use form (*) above, might it be further possible to use the
> hierarchy so that if I search for
>   "Elizabeth Way, Cambridgeshire"
> and a node has "place=Cambridge; is_in=Cambridgeshire" or "place=Cambridge;
> is_in=Cambridgeshire,England,UK" then it will find my Elizabeth Way
> (possibly among a few others). Ditto "Elizabeth Way, UK" etc. That's clearly
> considerably harder to implement, though I think it is just a join or series
> of joins depending on how the database is implemented.
> 
> David
> 
> 
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have fun,

SteveC steve at asklater.com http://www.asklater.com/steve/