[OSM-dev] JOSM: Several tags with same key
eddy.petrisor at gmail.com
Sun Apr 5 21:38:39 BST 2009
Pierre-André Jacquod a scris:
>>> I also see this as an error in the tagging-schema.
>>> We have way too many values for "amenity" so these collisions
>>> happen all the time. It`s not just bank+atm, it is also
>>> hotel+restaurant and many others.
>>> This way of tagging amenities simply grew without any regard
>>> for what was technically possible (most editors never properly supported
>>> multiple values for a key, thus noone was to use them as their work
>>> could be destroyed at any moment).
>> We could restructure most (all?) amenities to more speaking k/v-pairs,
>> by inventing thematic replacement-groups for amenity (and the similar
> I do not thing wee need to restructure it.
> Here some stats taking into account Austria, Switzerland, Finnland and
> amenity key has been used 40193 in nodes and 10346 in ways
> Amenity as key has been used with 431 different value tags.
> among theses 431 different values, there are 25 values with ; in them,
> all value (like fuel;fast_food or fuel;toilets ) being composed of
> values already used normally alone as amenity.
The fact that they are not used in the present in the form "a;b" doesn't
prove they wouldn't be used if it was established and recommended practice.
Because such a recommendation doesn't exist alters people's behaviour.
How much does that quantify to, I couldn't tell.
> This is at least 6% of key/value paar showing that the mapper thing the
> value belong to the same node... Actually this is more, since within the
> 431 entries, I saw quite a lot of entries due to misspelling. Without
> knowing all artificial double node (like I did) in order to map as it is
> Amenity has been combined with 384 other keys... some of them like atm,
> I found 638 times the combination
> amenity = bank
> atm = .....
> which shows that we are fare higher than 6% for the same point with
> different values since except manually it is not possible to know that
> the tag atm = yes means amenity = atm, but since this is already used
> for bank, I do a workaround....
> here below some details of my stat. I am now improving the performance
> of my program and try to let it run on europe. My end goal is to be able
> to create a kind of automatic dictionary of which key combination are
> used, and with which values... As soon as it can be presented in a
> better way, I will do it
"Imagination is more important than knowledge" A.Einstein
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