weight limit in short tons

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weight limit in short tons

Tobias Zwick
Hey there, as I was illustrating the
https://wiki.openstreetmap.org/wiki/Key:maxweight
article with some example signs and notes about pitfalls, I noticed that
the wiki says here that the weight *must always* be defined in metric units.

So, I also added a row in the examples table about the short tons to
metric tons conversion.

But now, I am wondering, if the claim "As per Map Features:Units, as of
September 2014 only metric units of weight (metric tonnes or kilograms)
are supported for this tag." is not a mistake.

Because...
1. https://wiki.openstreetmap.org/wiki/Map_Features/Units mentions "st"
(short tons) as a unit
2. there is also "mph" for speed limits
3. it seems that this rule would unnecessarily complicate the mapping in
the United States

Does anyone know anything about (a decision) that the weight may only be
specified in metric? Or was there a misinformed wiki-fiddler at work?

Cheers
Tobias

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Re: weight limit in short tons

Warin
On 26/01/19 19:55, Tobias Zwick wrote:
> Hey there, as I was illustrating the
> https://wiki.openstreetmap.org/wiki/Key:maxweight
> article with some example signs and notes about pitfalls, I noticed that
> the wiki says here that the weight *must always* be defined in metric units.

It is incorrect. The reference to

https://wiki.openstreetmap.org/wiki/Map_Features/Units

does not state a requirement, that pages only states a default unit.

I think going back to 2014 it even then only states default units .. no requirement.



>
> So, I also added a row in the examples table about the short tons to
> metric tons conversion.
>
> But now, I am wondering, if the claim "As per Map Features:Units, as of
> September 2014 only metric units of weight (metric tonnes or kilograms)
> are supported for this tag." is not a mistake.
>
> Because...
> 1. https://wiki.openstreetmap.org/wiki/Map_Features/Units mentions "st"
> (short tons) as a unit
> 2. there is also "mph" for speed limits
> 3. it seems that this rule would unnecessarily complicate the mapping in
> the United States
>
> Does anyone know anything about (a decision) that the weight may only be
> specified in metric? Or was there a misinformed wiki-fiddler at work?

Possibly someone taking 'default unit' as a required unit?

In any case it needs correction.


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Re: weight limit in short tons

Warin
The only problem is the 'ton'.

I n the USA 2,000 pounds
In the UK 2,240 pounds.


Resolving this? units 'ton us' and 'ton uk' ???

Fortunately most of the rest of the work has gone metric.

On 27/01/19 09:54, Warin wrote:

> On 26/01/19 19:55, Tobias Zwick wrote:
>> Hey there, as I was illustrating the
>> https://wiki.openstreetmap.org/wiki/Key:maxweight
>> article with some example signs and notes about pitfalls, I noticed that
>> the wiki says here that the weight *must always* be defined in metric
>> units.
>
> It is incorrect. The reference to
>
> https://wiki.openstreetmap.org/wiki/Map_Features/Units
>
> does not state a requirement, that pages only states a default unit.
>
> I think going back to 2014 it even then only states default units ..
> no requirement.
>
>
>
>>
>> So, I also added a row in the examples table about the short tons to
>> metric tons conversion.
>>
>> But now, I am wondering, if the claim "As per Map Features:Units, as of
>> September 2014 only metric units of weight (metric tonnes or kilograms)
>> are supported for this tag." is not a mistake.
>>
>> Because...
>> 1. https://wiki.openstreetmap.org/wiki/Map_Features/Units mentions "st"
>> (short tons) as a unit
>> 2. there is also "mph" for speed limits
>> 3. it seems that this rule would unnecessarily complicate the mapping in
>> the United States
>>
>> Does anyone know anything about (a decision) that the weight may only be
>> specified in metric? Or was there a misinformed wiki-fiddler at work?
>
> Possibly someone taking 'default unit' as a required unit?
>
> In any case it needs correction.
>
>


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Re: weight limit in short tons

Paul Allen
On Sat, 26 Jan 2019 at 23:28, Warin <[hidden email]> wrote:
The only problem is the 'ton'.

I n the USA 2,000 pounds
In the UK 2,240 pounds.

Resolving this? units 'ton us' and 'ton uk' ???

Why not use the terms that they are well known by when it is necessary to distinguish
between them?  The US ton is known as the "short ton" (which the original poster
mentioned) and the UK ton is known as the "long ton."  The metric ton is the "tonne."

Yes, there are other tons around, like the longweight and shortweight tons, but they
are archaic (as the long and short tons should be).

--
Paul


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Re: weight limit in short tons

Sergio Manzi


On 2019-01-27 00:42, Paul Allen wrote:
On Sat, 26 Jan 2019 at 23:28, Warin <[hidden email]> wrote:
The only problem is the 'ton'.

I n the USA 2,000 pounds
In the UK 2,240 pounds.

Resolving this? units 'ton us' and 'ton uk' ???

Why not use the terms that they are well known by when it is necessary to distinguish
between them?  The US ton is known as the "short ton" (which the original poster
mentioned) and the UK ton is known as the "long ton."  The metric ton is the "tonne."

Yes, there are other tons around, like the longweight and shortweight tons, but they
are archaic (as the long and short tons should be).

--
Paul


I've also always known them as "short ton" and "long ton" and I agree whith your choice, but...

actually "short ton" and "long ton" are the terms used in the U.S., while AFAIK Brits distinguish between "imperial ton" and "cental ton", so maybe we have a problem...

Sergio


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Re: weight limit in short tons

Paul Allen
On Sun, 27 Jan 2019 at 00:09, Sergio Manzi <[hidden email]> wrote:
I've also always known them as "short ton" and "long ton" and I agree whith your choice, but...

actually "short ton" and "long ton" are the terms used in the U.S., while AFAIK Brits distinguish between "imperial ton" and "cental ton", so maybe we have a problem...

Yeah, in the UK we're more likely to use "imperial ton" if we need to make it clear we're talking
about our ton and not the Merkin one.  But (theoretically) the UK doesn't use imperial tons any
more because they were excluded from terms used for trade in 1985.  The UK went metric
(apart from road signs in miles and beverages in pints).

I have no idea what a "cental ton" is.  Should I drink more covfefe?

It might not be a problem if we can get editor presets to offer UK/US/metric tons as options
and do the work behind the scenes.  Or perhaps we now understand why the wiki said
metric units only. :)

--
Paul


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Re: weight limit in short tons

Sergio Manzi
On 2019-01-27 01:32, Paul Allen wrote:
I have no idea what a "cental ton" is.  Should I drink more covfefe?

Aahahhahahh! :-) Nice, and I had quite a similar reaction when I first heard about it (by an English gentleman): "cental" from the Latin "centum" (one hundred), because the US short ton is 4 hundredweight of 100 lb, while the long ton is 112 lb 8 stones).

Sergio



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Re: weight limit in short tons

Sergio Manzi

... but now I have a doubt... I don't find any referenece... have I been pranked? :-/


On 2019-01-27 01:45, Sergio Manzi wrote:
On 2019-01-27 01:32, Paul Allen wrote:
I have no idea what a "cental ton" is.  Should I drink more covfefe?

Aahahhahahh! :-) Nice, and I had quite a similar reaction when I first heard about it (by an English gentleman): "cental" from the Latin "centum" (one hundred), because the US short ton is 4 hundredweight of 100 lb, while the long ton is 112 lb 8 stones).

Sergio



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Re: weight limit in short tons

Paul Allen
On Sun, 27 Jan 2019 at 00:49, Sergio Manzi <[hidden email]> wrote:

... but now I have a doubt... I don't find any referenece... have I been pranked? :-/

I thought perhaps you had, because I couldn't turn up anything on a google search.
Which is why I said I hadn't heard of it.   But I was puzzled when you responded that
the imperial hundredweight was "112 lb 8 stones" so I checked.  And found
https://en.wikipedia.org/wiki/Hundredweight.  So you were right about the cental.
Except in British English we used hundredweight in my youth because we had never
heard of "centum weight" or "quintal."  And, to be honest, even hundredweight
wasn't much used outside of people involved in bulk transportation of heavy
goods, so it was pretty much ounces, pounds, stones and tons for ordinary
people.

There are many more units of weight.  I dimly remember a very old Science Fiction
story in which aliens failed to invade the Earth because they were confused by all
the different units of weight involved.  I can't remember the name of the story or the
author, but I can remember that one of the bizarre units was the catty.

This way madness lies.  Some of these bizarre units of weight are still in use in
various parts of the world.  The link above has an image of a weight restriction
sign on Alderney (not part of the UK but a Crown Dependency) of 30cwt.  Which
is imperial cwt (or centum weight) not US cental.  I'm seriously starting to think
the wiki page adopted the most sensible strategy of saying that weights should
be in metric units.

Except for one problem.  The various tons and hundredweights are not units of
weight but of mass, so weight restrictions are given in mass units not weight
units.  We should be specifying weight restrictions in Newtons, dynes
poundals and slugs.

OK.  Let's deprecate weight restrictions.  Change the wiki to say weight restrictions
are not permitted. :)

--
Paul



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Re: weight limit in short tons

Warin
I have edited the units page to include the long ton.

      
https://wiki.openstreetmap.org/wiki/Map_Features/Units 
And edited the weight page to exclude the unit from the definition.
And also mention the tonne (BE!).

      
https://wiki.openstreetmap.org/wiki/Key:maxweight

      
It makes a few barleycorns of difference. 
(Barleycorns were used as a unit of weight ... and length just to confuse).
I too recall the hundredweight from my youth, but I don't recall the relationships. 
--------------
For those interested in old units, from wikipedia 
https://en.wikipedia.org/wiki/List_of_obsolete_units_of_measurement#Mass_or_weight

      
On 27/01/19 12:45, Paul Allen wrote:

      
      
On Sun, 27 Jan 2019 at 00:49, Sergio Manzi <[hidden email]> wrote:
  
    
  
  
    
... but now I have a doubt... I don't find any referenece... have
      I been pranked? :-/
I thought perhaps you had, because I couldn't turn up anything on a google search.
Which is why I said I hadn't heard of it.   But I was puzzled when you responded that
the imperial hundredweight was "112 lb 8 stones" so I checked.  And found
https://en.wikipedia.org/wiki/Hundredweight.  So you were right about the cental.
Except in British English we used hundredweight in my youth because we had never
heard of "centum weight" or "quintal."  And, to be honest, even hundredweight
wasn't much used outside of people involved in bulk transportation of heavy
goods, so it was pretty much ounces, pounds, stones and tons for ordinary
people.

        
There are many more units of weight.  I dimly remember a very old Science Fiction
story in which aliens failed to invade the Earth because they were confused by all
the different units of weight involved.  I can't remember the name of the story or the
author, but I can remember that one of the bizarre units was the catty.

        
This way madness lies.  Some of these bizarre units of weight are still in use in
various parts of the world.  The link above has an image of a weight restriction
sign on Alderney (not part of the UK but a Crown Dependency) of 30cwt.  Which
is imperial cwt (or centum weight) not US cental.  I'm seriously starting to think
the wiki page adopted the most sensible strategy of saying that weights should
be in metric units.

        
Except for one problem.  The various tons and hundredweights are not units of
weight but of mass, so weight restrictions are given in mass units not weight
 units.  We should be specifying weight restrictions in Newtons, dynes
poundals and slugs.

        
OK.  Let's deprecate weight restrictions.  Change the wiki to say weight restrictions
are not permitted. :)

        
-- 
Paul

        

        



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Re: weight limit in short tons

Paul Allen
On Sun, 27 Jan 2019 at 04:12, Warin <[hidden email]> wrote:
I have edited the units page to include the long ton.

For the benefit of mappers who do not understand the distinction or know how many
pounds there are in their local ton, it would be useful to indicate that the short ton
is part of the US customary units and the long ton part of the imperial units.

And you really do need the hundredweight.   Because dim memories of the past,
when I was too young to drive or take much interest in road signage, lead me
to conclude that the cwt was used for weight restrictions in the UK back then.
And, according to https://en.wikipedia.org/wiki/Hundredweight, is still used in
some parts of the world for that purpose.  That's the imperial cwt in Guernsey,
but the US cwt might be in use in parts of the US.

--
Paul


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Re: weight limit in short tons

OSMDoudou
In reply to this post by Tobias Zwick
Indeed, it's very strange to require mappers do the maths when there is a notation to indicate the unit and let the renderers do the maths.


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Re: weight limit in short tons

Sergio Manzi

On 2019-01-27 17:53, OSMDoudou wrote:
> Indeed, it's very strange to require mappers do the maths when there is a notation to indicate the unit and let the renderers do the maths.


Hi!

Why do you talk about math? Do you expect renderers to automatically convert weights from whatever unit to the one you're using for your locale? Or maybe to use those weight limits as a parameter for the router?

If this is what you want, then the problem is the parsing of the string used to define the units used within the tag: as already pointed out, "ton" is the symbol used for both "long" (UK, imperial) and "short" (US, cental) tons, so we must find a "controlled" way to indicate which measurement system is in use for the tag.

If instead we are not interested in possible computations, then we can live with the customary way to indicate tons, and deduce from the location which kind of tons we are talking about, same as if we were traveling to the place and see the indication on a sign, with our own eyes.

And indeed the same heuristics can possibly be applied to a parser...

Sergio



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Re: weight limit in short tons

Warin
On 28/01/19 04:24, Sergio Manzi wrote:
On 2019-01-27 17:53, OSMDoudou wrote:
Indeed, it's very strange to require mappers do the maths when there is a notation to indicate the unit and let the renderers do the maths. 

Hi!

Why do you talk about math? Do you expect renderers to automatically convert weights from whatever unit to the one you're using for your locale? Or maybe to use those weight limits as a parameter for the router?

Yes. The renders have to cope with different units for speed, length, height, elevation etc. so why not weight?

As has been said before - far easier to find an error in the rendering and correct it than 
find an error in the maths used by a single entry or a single mapper in the data base. 

If this is what you want, then the problem is the parsing of the string used to define the units used within the tag: as already pointed out, "ton" is the symbol used for both "long" (UK, imperial) and "short" (US, cental) tons, so we must find a "controlled" way to indicate which measurement system is in use for the tag.
On the wiki page for units there is now the default unit of the tonne (metric ton for usa), and then alternative units of st for short ton, lt for long ton. 
https://wiki.openstreetmap.org/wiki/Map_Features/Units
I just recently add the lt for long ton, the short ton was already there. If you want to add other units .. do so. 


If the mapper uses the unit 'ton' then they have not complied with the wiki and 
there would need to be a decision on using it at all, if using it then what unit is to be used. 

If instead we are not interested in possible computations, then we can live with the customary way to indicate tons, and deduce from the location which kind of tons we are talking about, same as if we were traveling to the place and see the indication on a sign, with our own eyes.

And indeed the same heuristics can possibly be applied to a parser...

Sergio




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Re: weight limit in short tons

Andrew Hain
As a quick objection from a British mapper old enough to remember obsolete measurements: long tons are pointless, too similar to toes and not used on signs anywhere I know of, the abbreviation st can stand for a stone (6.3kg or 14lb).

--
Andrew

From: Warin <[hidden email]>
Sent: 27 January 2019 23:11
To: [hidden email]
Subject: Re: [Tagging] weight limit in short tons
 
On 28/01/19 04:24, Sergio Manzi wrote:
On 2019-01-27 17:53, OSMDoudou wrote:
Indeed, it's very strange to require mappers do the maths when there is a notation to indicate the unit and let the renderers do the maths. 

Hi!

Why do you talk about math? Do you expect renderers to automatically convert weights from whatever unit to the one you're using for your locale? Or maybe to use those weight limits as a parameter for the router?

Yes. The renders have to cope with different units for speed, length, height, elevation etc. so why not weight?

As has been said before - far easier to find an error in the rendering and correct it than 
find an error in the maths used by a single entry or a single mapper in the data base. 

If this is what you want, then the problem is the parsing of the string used to define the units used within the tag: as already pointed out, "ton" is the symbol used for both "long" (UK, imperial) and "short" (US, cental) tons, so we must find a "controlled" way to indicate which measurement system is in use for the tag.
On the wiki page for units there is now the default unit of the tonne (metric ton for usa), and then alternative units of st for short ton, lt for long ton. 
https://wiki.openstreetmap.org/wiki/Map_Features/Units
I just recently add the lt for long ton, the short ton was already there. If you want to add other units .. do so. 


If the mapper uses the unit 'ton' then they have not complied with the wiki and 
there would need to be a decision on using it at all, if using it then what unit is to be used. 

If instead we are not interested in possible computations, then we can live with the customary way to indicate tons, and deduce from the location which kind of tons we are talking about, same as if we were traveling to the place and see the indication on a sign, with our own eyes.

And indeed the same heuristics can possibly be applied to a parser...

Sergio




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Re: weight limit in short tons

Warin
Point. However where have you seen a weight limit in stone? 
Possibly a lift? Though they usually just say number of people .. and beep if over loaded.
The abbreviation form short ton has been there a while. 

On 29/01/19 08:51, Andrew Hain wrote:
As a quick objection from a British mapper old enough to remember obsolete measurements: long tons are pointless, too similar to toes and not used on signs anywhere I know of, the abbreviation st can stand for a stone (6.3kg or 14lb).

--
Andrew

From: Warin [hidden email]
Sent: 27 January 2019 23:11
To: [hidden email]
Subject: Re: [Tagging] weight limit in short tons
 
On 28/01/19 04:24, Sergio Manzi wrote:
On 2019-01-27 17:53, OSMDoudou wrote:
Indeed, it's very strange to require mappers do the maths when there is a notation to indicate the unit and let the renderers do the maths. 
Hi!

Why do you talk about math? Do you expect renderers to automatically convert weights from whatever unit to the one you're using for your locale? Or maybe to use those weight limits as a parameter for the router?

Yes. The renders have to cope with different units for speed, length, height, elevation etc. so why not weight?

As has been said before - far easier to find an error in the rendering and correct it than 
find an error in the maths used by a single entry or a single mapper in the data base. 
If this is what you want, then the problem is the parsing of the string used to define the units used within the tag: as already pointed out, "ton" is the symbol used for both "long" (UK, imperial) and "short" (US, cental) tons, so we must find a "controlled" way to indicate which measurement system is in use for the tag.
On the wiki page for units there is now the default unit of the tonne (metric ton for usa), and then alternative units of st for short ton, lt for long ton. 
https://wiki.openstreetmap.org/wiki/Map_Features/Units
I just recently add the lt for long ton, the short ton was already there. If you want to add other units .. do so. 


If the mapper uses the unit 'ton' then they have not complied with the wiki and 
there would need to be a decision on using it at all, if using it then what unit is to be used. 

If instead we are not interested in possible computations, then we can live with the customary way to indicate tons, and deduce from the location which kind of tons we are talking about, same as if we were traveling to the place and see the indication on a sign, with our own eyes.

And indeed the same heuristics can possibly be applied to a parser...

Sergio





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Re: weight limit in short tons

Minh Nguyen-2
In reply to this post by Warin
On 2019-01-26 15:27, Warin wrote:
> The only problem is the 'ton'.
>
> I n the USA 2,000 pounds
> In the UK 2,240 pounds.
>
>
> Resolving this? units 'ton us' and 'ton uk' ???

I've been converting to pounds (lbs), which avoids this ambiguity with
precise conversions. Apparently I'm not alone. [1] But I'd welcome a
well-supported convention for U.S. tons so that data consumers don't
have to guess whether the sign is expressed in pounds or tons.

[1] https://taginfo.openstreetmap.org/tags/maxweight=10000%20lbs

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Re: weight limit in short tons

Warin
On 31/01/19 07:20, Minh Nguyen wrote:

> On 2019-01-26 15:27, Warin wrote:
>> The only problem is the 'ton'.
>>
>> I n the USA 2,000 pounds
>> In the UK 2,240 pounds.
>>
>>
>> Resolving this? units 'ton us' and 'ton uk' ???
>
> I've been converting to pounds (lbs), which avoids this ambiguity with
> precise conversions. Apparently I'm not alone. [1] But I'd welcome a
> well-supported convention for U.S. tons so that data consumers don't
> have to guess whether the sign is expressed in pounds or tons.
>
> [1] https://taginfo.openstreetmap.org/tags/maxweight=10000%20lbs
>
Better demonstration of use
https://taginfo.openstreetmap.org/search?q=lbs#values


Over 1,000 instances.

Some use of kg too .. but that is harder to demonstrate.

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Re: weight limit in short tons

Kevin Kenny-3
I wonder whether we are arguing hypotheticals here.

Is there still highway signage, anywhere, with weight limits in long
tons? I don't know, but I'd have imagined that the UK would have gone
to metric signs a long time ago. (I imagine that there are still
historic bridges with the old placards on them - but that's like
coding '5 shillings fine for driving a waggon across this bridge at a
pace faster than a walk' on the old placard.)

I've traveled the US fairly extensively, and I've never seen a traffic
sign in cwt. (Or indeed, anything else, although I understand that
it's still a unit in wholesale commerce of some goods.) Instead of
saying '30 cwt', a load sign here would say '1.5 tons' or '1½ tons' or
'3000 lbs'.

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Re: weight limit in short tons

Warin
On 01/02/19 11:28, Kevin Kenny wrote:
I wonder whether we are arguing hypotheticals here.
Well long tones (lt) helps explain short tons. 

Both lbs and kg appear in the data base .. so I'll add them. 
So do 'person', I assume for a lift/elevator. Add that too. 
There are some strange units ..example 'm' ? 


Is there still highway signage, anywhere, with weight limits in long
tons? I don't know, but I'd have imagined that the UK would have gone
to metric signs a long time ago. (I imagine that there are still
historic bridges with the old placards on them - but that's like
coding '5 shillings fine for driving a waggon across this bridge at a
pace faster than a walk' on the old placard.)

I've traveled the US fairly extensively, and I've never seen a traffic
sign in cwt. (Or indeed, anything else, although I understand that
it's still a unit in wholesale commerce of some goods.) Instead of
saying '30 cwt', a load sign here would say '1.5 tons' or '1½ tons' or
'3000 lbs'.
There are 2 in the data base with 30 cwt ... 
Way 403519212
Way 91738326

    
Both in the UK and both parking areas. 

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