[Talk-GB] Errors in Street Names in Addresses

[Robert Whittaker (OSM lists)]

Following on from last quarter's post-code and addresses project, I've
been doing a bit more playing around with UK address data from OSM.
I've put together a new report at
http://robert.mathmos.net/osm/addresses/street-warnings/ which
provides lists of potential issues in street names (e.g. addr:street=*
values [1]) that appear in addresses on OSM objects [2].

In general, all the premises with the same postcode should have the
same street name in their address [3]. The report flags cases where
this isn't true, as well as potential anomalies in the street names
(e.g. odd punctuation, abbreviations), and also cases where there is
no street given. Key things it will help mappers detect are
typos/inconsistencies in street names within addresses and
typos/errors in addr:postcode values that put the wrong postcode on an
object a few streets away from where it should be. The data should be
updated roughly once a week.

Please have a look if you're interested, and see if you find it useful
in picking up mistakes. Also let me know if you've got any
ideas/suggestions for improvements.

Some technical notes:

[1] Due to the way addresses are recorded in OSM, and the formatting
of UK addresses by Royal Mail (see also [3] below), the "Street Name"
for an object is picked up by the tool from a variety of tags.
Currently it uses the following, in order of precedence: the
addr:place tag, the addr:parentstreet tag, the addr:street tag, the
name tag on associatedStreet relation if present, and the
addr:locality tag

[2] Since the tool uses data collected for analysing postcodes, it
only considers objects with valid  addr:postcode tags.

[3] It's not quite true to say that a single postcode unit can only
have addresses on a single street. First, there are a small number of
historic anomalies where a single postcode unit does cover more than
one street. Secondly, some addresses contain two street names, a main
street and a so-called "dependent street". Apart from the historic
anomalies, a single postcode should only cover one main street, but
can include more than one dependent street. (The tool will not see the
dependent streets as different if both streets are tagged, either as
addr:substreet and addr:street or as addr:street and
addr:parentstreet.) Finally, some addresses (e.g. in small hamlets) do
not officially contain a street name and just have a house name and
locality. So if the streets have names and these have been added to an
OSM object, it may appear that a single postcode covers more than one
street. (The tool will ignore different streets if addr:place is used
for the common place/hamlet name.)

Robert.

-- 
Robert Whittaker