[Talk-us] what do we mean by geocoding?

[Serge Wroclawski]

On Sun, Jun 23, 2013 at 12:09 PM, Mark Newnham <mark at newnhams.com> wrote:

>    a. Both Google and Openstreetmap don't know anything about actual
> addresses in the US. For reverse geocode purposes, they just guess based on
> the approximate lat/long location.
>
>   b.  An easy example to show you is this -  A search for "6188 South Poplar
> St, Centennial. CO" in both google and openstreetmap will both return
> results - Google will even give you a Streetview. But that property simply
> doesn't exist.  It never has/

It's easy to understand how you came to this conclusion, but what's
happening inside is a bit different than this.

What's happenijng when you search for this address in OSM is that
you're using a service called Nominatim. What Nominatim is doing is
saying "I don't know about this address, but I do know about this
street, so I'm going to do my best to give you the information you've
asked for".

If you click on the details link in Nominatim from this query, it says
that this address is estimated.

I can't speak for Google and what its geocoder is doing.

> USPS provides an easy to understand, comprehensive addressing method that
> would allow OSM to provide a consistent addressing methodology to addresses.
> For example, An armchair mapper might map an address like  North Caley as
> North Caley, Nort Caley NTH Caley or N Caley. (These are the most common
> ways by the way for manually entered addresses).

Yes, but they won't give us access to this data, so it's a bit of a moot point.

The data that Bryce is talking to us about is post office locations.
And even this, as we've begun to dig into it, is of limited value to
the project, since we have to do the geocoding for this data.

It's still worth discussing with USPS, both for political and
technical reasons, but this is a very limited subset of our data and
not the same as the USPS "crown jewel" of all US addresses.

- Serge