[Geocoding] Questions about Nominatim geocoder

[Sarah Hoffmann]

Hi,

On Wed, Apr 10, 2013 at 05:01:11PM +0000, Coulombe, Greg wrote:
> I have been experimenting with the Nominatim to handle geocoding freeform addresses and have observed a few issues and I'm wondering if there are workarounds that people might recommend. Here are some of the things I've observed:
> 
>   1.  Road exists but address has wrong locality. There seem to be lots of these kinds of cases in which the road exists but it's not in the locality specified in the input and so the geocoder fails. This seems to be a common problem for suburban addresses. Is there a way to enable a search that looks at nearby localities? Examples:
>      *   "15083 W. FORD DRIVE, PARK HILL, OK, 74451" ("Cherokee", not "park hill")
>      *   "1125 Pond Side Dr, Colorado Springs, CO, 80911" -> Is in "El Paso County", not Colorado Springs
>      *   "279 E.G. Fowler, Waycross, GA, 31503" -> Road is actually in neighboring county ("brantley")
>      *   "1 Tranquility Base, Huntsville, AL, 35805" -> Road is actually in Madison (which is, in turn, part of the Huntsville metro area)

There is limited support for that kind of fuzzy search, although it has been 
more and more restricted because it caused a lot of false positives (and lots
of complaints).

>   2.  Fallback: if the street component of the address is not parseable or not found, can the geocoder be configured to fall back to the next less granular address component (i.e. house number --> street --> city --> province). For example: "Foobar, Madison, AL" should resolve to "Madison, AL". This would be the case for post office boxes as well – the geocoder could just return the city instead of failing altogether for those addresses.

Currently not possible but on the todo list. Not quite as trivial a matter on a
world-wide search engine because there are some countries who like to spell
their addresses backwards (province, city, street, house number)

>   3.  Zip+4: the search seems to fail for Zip+4 zip codes. Should these be filtered out in the input or is there a way to get the geocoder to ignore them?

It might be a good idea to filter out ZIP codes in general if you do complete
address searches like the ones above. ZIP code support is rather limited at
the moment and needs a thorough make over.

Sarah