At present the string "none" is actually a value, the interpretation of which
is specific to the key "maxspeed" . Maybe we should promote it to the
equivalent of NULL in SQL.
On 24 January 2016 10:43:16 CET, Tijmen Stam <mailingli...@iivq.net> wrote:
>With the value "none"
>
>For example on German Autobahnen, where you can drive as fast as you
>want is "maxspeed=none" which is different from having maxspeed not
>set:
>this means maxspeed is unknown or not tagged yet.
>
>
>
>On 20-01-16 09:06, Colin Smale wrote:
>> Exactly.
>>
>> If a missing value (i.e. use the default) is not the same as
>explicitly
>> having NO value, how do you override the default with "no value"?
>>
>> --colin
>>
>> On 2016-01-20 08:50, Gerd Petermann wrote:
>>
>>> I don't think that the meaning really depends on the position. My
>>> understanding is that the
>>>
>>> complete value (e.g. "80||" ) is parsed by splitting it into
>separate
>>> strings at each pipe symbol.
>>>
>>> Result: three strings: "80" , "",""
>>>
>>> The value "|80|" also gives three strings: "","80",""
>>>
>>> Another point is that an empty value means "use the default", which
>can
>>>
>>> only make sense in special cases like this.
>>>
>>> Gerd
>>>
>>>
>>>
>------------------------------------------------------------------------
>>> *Von:* Colin Smale <colin.sm...@xs4all.nl>
>>> *Gesendet:* Mittwoch, 20. Januar 2016 08:23
>>> *An:* Tag discussion, strategy and related tools
>>> *Betreff:* Re: [Tagging] Removing name_1 and alt_name_1 from Wiki
>>>
>>> I meant that there is a value missing "between the pipes", which at
>a
>>> slightly higher semantic level can mean "use the default". A
>>> definition which varies according to position doesn't feel
>well-formed
>>> to me.
>>>
>>> //colin
>>>
>>> On 2016-01-20 08:10, Gerd Petermann wrote:
>>>
>>> Colin Smale wrote
>>>
>>> The "lanes" tag family uses a different delimiter ("|"),
>sometimes
>>> together with a semicolon to make a kind of 2-d array. A
>>> double pipe
>>> ("||") indicates a missing value there. Wouldn't it be nice
>if
>>> we were
>>> consistent?
>>>
>>>
>>> That is new to me. My understanding of a double pipe is that
>>> described here:
>>>
>http://wiki.openstreetmap.org/wiki/Proposed_features/lanes_General_Extension#Default_values
>>>
>>> Proposed features/lanes General Extension - OpenStreetMap Wiki
>>>
><http://wiki.openstreetmap.org/wiki/Proposed_features/lanes_General_Extension#Default_values>
>>> wiki.openstreetmap.org
>>> A simple, straightforward extension of existing tags to specify
>>> properties not only for a way as whole but for the lanes of the
>>> way instead. Based on this general ...
>>>
>>>
>>> which indicates that a double pipe means one or two default
>values,
>>> depending on the position.
>>> At the end of the value, it means two default values.
>>>
>>> Gerd
>>>
>>>
>>>
>>> --
>>> View this message in context:
>>>
>http://gis.19327.n5.nabble.com/Removing-name-1-and-alt-name-1-from-Wiki-tp5864465p5865207.html
>>>
><http://gis.19327.n5.nabble.com/Removing-name-1-and-alt-name-1-from-Wiki-tp5864465p5865207.html>
>>> Sent from the Tagging mailing list archive at Nabble.com.
>>>
>>> _______________________________________________
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>>>
>>>
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>>
>>
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