[OSM-talk] Czech address system

[Radomír Černoch]

Hi,

first of all I would like to say sorry for bringing up "the address
issue" once again. I want to ask you about a system for alternative
(or secondary) house numbers.

In Slovakia and Czech Republic we have a system for numbering houses
not only on streets (the standard 'housenumber'), but also by a unique
number within a town, village or suburb. The problem is that sometimes
the 'housenumber' is not present on a house and the alternative number
is the only way of identifying it. Therefore we need to get this
number painted. Moreover Germany and Austria can use the same field
for "Konskriptionsnummer"
(http://de.wikipedia.org/wiki/Konskriptionsnummer).

Here is the most suitable solution, which has emerged from numerous discussions:
1) Currently a 'building' having 'addr:housenumber' is painted with
black letters. Anything else having 'addr:housenumber' is painted with
black letters and a "white glow" around it.
2) The proposal is to paint any 'addr:housenumber' in a uniform
fashion by black letters and a white glow around.
3) The black letters without glow can be used to paint the alternative
house numbers. Using text without glow would also emphasize that this
system is not as important as the main one with glowing numbers.

Would you agree with such a change of mapnik / osmarender style?

There is one associated question: What key shall be used for this
system? Current map uses 'addr:alternatenumber' just like wiki
suggests on a page titled 'Key:addr'. However before discovering the
wiki article, there was a proposal to rename this tag to 'addr:ref'
with considerable arguments:

2009/5/13 Shaun McDonald <osm at shaunmcdonald.me.uk>:
> Hi Radek,
>
> addr:ref is shorter, thus less likely to have error in the data entry. A
> reference is generally used for something that is unique within a certain
> region, such as a country or a city. It is also smaller which means that it
> will take less space in the DB and downloads. ref is something that is
> rendered for some other things, thus addr:ref is more likely to be rendered.
>
> The probability of typos being high is a strong reason to avoid
> addr:alternatehousenumber.

Personally I do not feel strong opinion about this. If you do, please say so.

Lastly there is one option, which tends to be proposed quite often: To
put the 'alternatenubmer' into 'housenumber' field, when the house has
no 'housenumber'. This solution would avoid changing of renderers'
styles. However this has always been refused, because of being
non-systematic. When searching for an address, it is necessary to
distinguish, whether the user wants the main or alternative house
number.

Yours sincerely,
Radomir Cernoch



DETAILED DESCRIPTION OF THE CZECH ADDRESS SYSTEM:
We have the standard 'housenumber', which defines the order of houses
on a street and therefore this number makessense only in combination
with the street name. This system is used by most people as it is easy
to remember and hence this number is rendered on OSM maps. In Czech
this number is called "číslo orientační."

The second system, which we currently store in 'alternatenumber'
("číslo popisné") defines a unique number of a house within a
village/town or suburb. Houses are ordered historically, the oldest
has number 1, the newest might have 4029. Therefore houses 4028 and
4029 can be on opposite sides of the town. This system is used for
administration and in small villages it serves as the primary system,
since it is not crucial to adopt the 'housenumber' system if eg. the
municipality consists only of one street.

-- 
Radomir Cernoch
+44 750 708 8293 / +420 607 282 031
Email, Jabber: radomir.cernoch at gmail.com