[Tagging] source:maxspeed vs. maxspeed:type

Martin Vonwald imagic.osm at gmail.com
Sat Feb 23 11:32:54 UTC 2013


Hi!

2013/2/23 Philip Barnes <phil at trigpoint.me.uk>:
> On Fri, 2013-02-22 at 17:38 +0100, Martin Vonwald wrote:
>> Hi!
>>
>> Recently the use of the key maxspeed:type was documented in the wiki
>> (see [1] and [2]). It seems to be used in the UK for the same purpose
>> as source:maxspeed. I quote: "In the UK the general practice is to use
>> the maxspeed:type tag as the source:*=* should be for how the data was
>> collected, not how it was derived. "
>>
>> Well - there's a point. Yes, I know how often source:maxspeed is
>> tagged (241,738 times). But besides being tagged, is it "used" for
>> anything at the moment?
>>
> It is used to indicated a speed limit that is not explicitly signposted,
> such as by a the National Speed Limit sign
> http://wiki.openstreetmap.org/w/index.php?title=File:UK_traffic_sign_671.svg&page=1

> The motorway 'chopsticks' sign, or a change from single to dual
> carriageway.
>
> I am not aware of it being used, but will make changes a lot easier if
> the limits ever change. There is discussion about raising the motorway
> limit to 80mph.

You can achieve exactly the same with maxspeed:type. And usually we
use the key source for how we collect the data, but not the key
source:maxspeed . In my opinion maxpeed:type is also a much more
intuitive key than source:maxspeed.

As in the UK examples in the wiki we (potentially) would get an
additional piece of information and would be more consistent.
maxspeed=50  -> what is the speed limit?
maxspeed:type=AT:urban -> what kind of speed limit is is?
source:maxspeed=survey  -> how was the information regarding the speed
limit collected?

But I'm just asking questions. If no-one cares that's perfectly ok for
me and I'll keep on using source:maxspeed.

regards,
Martin



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