Re: [talk-au] Unclassified Highway Speeds

[stevea]

I say this "from a great distance," but here goes:  if you consider that 
AU:Urban or AU:rural (and/or similar) are QUITE LOOSE compared to EXPLICIT 
tagging, you might be able to nudge things ahead in a semantic parsing sense.  
It won't be perfect, it likely never will be (ambiguities about whether it's 
valid to "do" this, or that...are never-ending) but it can "oomph things 
forward" a bit, sometimes more.  Not much more than that, but better than 
nothing.

This is tough stuff, and it is context-driven as to where there is a boundary 
and where fuzzy becomes "um, I'm shrugging my shoulders."  Keep an eye on that.

> On Apr 21, 2022, at 12:09 AM, Andrew Hughes  wrote:
> 
> Thank you all for your contributions to this thread so far, much appreciated!
> 
> Please correct me if you disagree with this...
> 1. So it would seem that ALL roads should be tagged with maxspeed and 
> assigned a numeric value (kph), where the maxspeed is known.
> 2. Supplementary to #1. the maxspeed:type tag also adds information of value 
> because it can indicate if the maxspeed is "signed" or on the basis of it 
> being unsigned and relative to its geographical ("AU:Urban" or "AU:rural") 
> location.
> 
> Important question...
> The guidelines also suggest that the use of maxspeed = "AU:Urban" or 
> "AU:rural" without a maxspeed tag could indicate that this has not been 
> surveyed. Adding this tag (with these values) without a maxspeed is also 
> encouraged as it improves the data such that the maxspeed can be assumed with 
> far greater accuracy (50pkh/60kph NT or 100kph), and loosely indicates the 
> survey status.
> 
> Cheers,
> AH



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Re: [talk-au] Unclassified Highway Speeds

[Andrew Hughes]

Thank you all for your contributions to this thread so far, much
appreciated!

*Please correct me if you disagree with this...*
1. So it would seem that ALL roads should be tagged with maxspeed and
assigned a numeric value (kph), where the maxspeed is known.
2. Supplementary to #1. the maxspeed:type tag also adds information of
value because it can indicate if the maxspeed is "signed" or on the basis
of it being unsigned and relative to its geographical ("AU:Urban" or
"AU:rural") location.

*Important question...*
The guidelines also suggest that the use of maxspeed = "AU:Urban" or
"AU:rural" without a maxspeed tag could indicate that this has not been
surveyed. Adding this tag (with these values) without a maxspeed is also
encouraged as it improves the data such that the maxspeed can be assumed
with far greater accuracy (50pkh/60kph NT or 100kph), and loosely indicates
the survey status.

Cheers,
AH


On Thu, 21 Apr 2022 at 11:36, Andrew Harvey 
wrote:

>
>
> On Wed, 20 Apr 2022 at 14:58, Dian Ågesson  wrote:
>
>> Hey Andrew,
>>
>> I’m chiming in as I encountered this issue documenting the “cleaned up”
>> Roads tagging guidelines. (
>> https://wiki.openstreetmap.org/wiki/Australian_Tagging_Guidelines/Roads)
>>
>>
>> The tagging guidelines (both prior to, and following cleanup) state it is
>> good practice in Australia to tag every road with a maxspeed.
>>
>> The early guidelines say that the implicit speed limits have not been
>> widely adopted in Australia, but this no longer appears to be true.
>>
> I would agree that it's good practice to tag every road with a maxspeed.
> https://wiki.openstreetmap.org/wiki/Good_practice#Don.27t_map_local_legislation_if_not_bound_to_specific_objects
>  does
> seem to confirm that. Generally being more specific with your tagging
> especially when confirmed on the ground is better.
>
> Similar for surface=asphalt, it used to be the case that you wouldn't
> bother tagging this as you assume it was the case if no surface was tagged,
> but to improve data quality and to distinguish this from "yet to be
> surveyed", and with the rise of editors like iD which give you an explicit
> dropdown or checkbox and StreetComplete which asks for every feature and
> needs an explicit tag to know it's been checked on the ground, it's more
> acceptable to always tag.
>
>
>> In use is both the maxspeed:type tag and source:maxspeed tag.
>> Unfortunately, the earlier guidelines offers advice on the usage of the
>> source:maxspeed tag that is contradictory to the global page. (It suggests
>> local_knowledge to mark implicit speed limits rather than AU:urban). The
>> maxspeed:type tag does not have this contradiction.
>>
>> I am not sure if leaving the maxspeed blank (or using a non-numeric
>> value) would be a good idea; using a non numeric value in maxspeed seems to
>> be much less preferred globally than the alternative methods. I documented
>> maxspeed:type rather than source:maxspeed following a discord discussion,
>> but I believe either of those two schemes are preferable to using
>> maxspeed=AU:urban.
>>
>
> I think those are useful in addition to the maxspeed tag, as they indicate
> if the maxspeed value came from a signpost/road marking, or due to implied
> legal defaults eg in NSW residential roads are 50km/h unless otherwise
> signposted.
>
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Re: [talk-au] Unclassified Highway Speeds

[Andrew Harvey]

On Wed, 20 Apr 2022 at 14:58, Dian Ågesson  wrote:

> Hey Andrew,
>
> I’m chiming in as I encountered this issue documenting the “cleaned up”
> Roads tagging guidelines. (
> https://wiki.openstreetmap.org/wiki/Australian_Tagging_Guidelines/Roads)
>
>
> The tagging guidelines (both prior to, and following cleanup) state it is
> good practice in Australia to tag every road with a maxspeed.
>
> The early guidelines say that the implicit speed limits have not been
> widely adopted in Australia, but this no longer appears to be true.
>
I would agree that it's good practice to tag every road with a maxspeed.
https://wiki.openstreetmap.org/wiki/Good_practice#Don.27t_map_local_legislation_if_not_bound_to_specific_objects
does
seem to confirm that. Generally being more specific with your tagging
especially when confirmed on the ground is better.

Similar for surface=asphalt, it used to be the case that you wouldn't
bother tagging this as you assume it was the case if no surface was tagged,
but to improve data quality and to distinguish this from "yet to be
surveyed", and with the rise of editors like iD which give you an explicit
dropdown or checkbox and StreetComplete which asks for every feature and
needs an explicit tag to know it's been checked on the ground, it's more
acceptable to always tag.


> In use is both the maxspeed:type tag and source:maxspeed tag.
> Unfortunately, the earlier guidelines offers advice on the usage of the
> source:maxspeed tag that is contradictory to the global page. (It suggests
> local_knowledge to mark implicit speed limits rather than AU:urban). The
> maxspeed:type tag does not have this contradiction.
>
> I am not sure if leaving the maxspeed blank (or using a non-numeric value)
> would be a good idea; using a non numeric value in maxspeed seems to be
> much less preferred globally than the alternative methods. I documented
> maxspeed:type rather than source:maxspeed following a discord discussion,
> but I believe either of those two schemes are preferable to using
> maxspeed=AU:urban.
>

I think those are useful in addition to the maxspeed tag, as they indicate
if the maxspeed value came from a signpost/road marking, or due to implied
legal defaults eg in NSW residential roads are 50km/h unless otherwise
signposted.
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Re: [talk-au] Unclassified Highway Speeds

[Graeme Fitzpatrick]

On Wed, 20 Apr 2022 at 15:02, stevea  wrote:

> At this point, I believe I am some Yank who babbles too much.
>

Not at all, AFAIK! :-)

 Thanks

Graeme
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Re: [talk-au] Unclassified Highway Speeds

[stevea]

Very nice to see this discussion.  At this point, I believe I am some Yank who 
babbles too much.
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Re: [talk-au] Unclassified Highway Speeds

[Dian Ågesson]

Hey Andrew,

I'm chiming in as I encountered this issue documenting the "cleaned up" 
Roads tagging guidelines. 
(https://wiki.openstreetmap.org/wiki/Australian_Tagging_Guidelines/Roads)


The tagging guidelines (both prior to, and following cleanup) state it 
is good practice in Australia to tag every road with a maxspeed.


The early guidelines say that the implicit speed limits have not been 
widely adopted in Australia, but this no longer appears to be true.


In use is both the maxspeed:type tag and source:maxspeed tag. 
Unfortunately, the earlier guidelines offers advice on the usage of the 
source:maxspeed tag that is contradictory to the global page. (It 
suggests local_knowledge to mark implicit speed limits rather than 
AU:urban). The maxspeed:type tag does not have this contradiction.


I am not sure if leaving the maxspeed blank (or using a non-numeric 
value) would be a good idea; using a non numeric value in maxspeed seems 
to be much less preferred globally than the alternative methods. I 
documented maxspeed:type rather than source:maxspeed following a discord 
discussion, but I believe either of those two schemes are preferable to 
using maxspeed=AU:urban.


Dian

On 2022-04-20 13:45, Andrew Hughes wrote:


Hi All,

First, I thought the tagging guidelines were "don't tag unless it's a 
non-default value" (my language to describe this might be inaccurate, 
feel free to improve). If this is true, then I shouldn't tag rural ALL 
roads with  maxspeed. It's only those that are "non-default".


Can anyone please confirm the above please?

Secondly, it does look like there is a tagging for implicit (speed) 
values as per  
https://wiki.openstreetmap.org/wiki/Key:maxspeed#Implicit_maxspeed_values 
 [1]

maxspeed = AU:urban
maxspeed = AU:rural

I believe that the above is better than tagging 50kph, 60kph or 100kph 
- because a change in legislation (as has happened in the past) can 
change is without tags needing to be updated.


But that all being said, I would still be tagging all roads and not 
just those that are "non-default" on the ground. Which contradicts the 
first point (if it is true that is).


This feels like a distinct gap in OSM (as others have pointed out). But 
this is one I would like to know how to deal with.


Perhaps area's could be tagged with maxspeed=AU:urban or 
maxspeed=AU:rural  to define "implicit speed areas"? I think this might 
be what is missing. Thoughts?


Thanks for reading
AH

On Wed, 20 Apr 2022 at 10:30, Graeme Fitzpatrick 
 wrote:


In regard to defaults, the default 50kph Qld (Oz-wide?) urban 
residential limit should apply around here, & sure enough, most 
streets are 50. But we also have some residential streets posted as 
40, 60 & 70, as well as 40 conditional school zones.


So I assume (using that terrible word! :-)) that actually tagging a 
speed limit on a road overrides the default?


& while I've seen reference to Default Qld Residential speed limit on 
the map, I've also noticed while driving around that OSMAND isn't 
showing a speed limit?


Thanks

Graeme
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Links:
--
[1] 
https://wiki.openstreetmap.org/wiki/Key:maxspeed#Implicit_maxspeed_values___
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Re: [talk-au] Unclassified Highway Speeds

[Andrew Hughes]

Hi All,

First, I thought the tagging guidelines were "don't tag unless it's a
non-default value" (my language to describe this might be inaccurate, feel
free to improve). If this is true, then I shouldn't tag rural ALL
roads with  maxspeed. It's only those that are "non-default".

*Can anyone please confirm the above please?*

Secondly, it does look like there is a tagging for implicit (speed) values
as per
https://wiki.openstreetmap.org/wiki/Key:maxspeed#Implicit_maxspeed_values

maxspeed = AU:urban
maxspeed = AU:rural

I believe that the above is better than tagging 50kph, 60kph or 100kph -
because a change in legislation (as has happened in the past) can change is
without tags needing to be updated.

But that all being said, I would still be tagging all roads and not just
those that are "non-default" on the ground. *Which contradicts the first
point (if it is true that is).*

This feels like a distinct gap in OSM (as others have pointed out). But
this is one I would like to know how to deal with.

Perhaps area's could be tagged with maxspeed=AU:urban or maxspeed=AU:rural
to define "implicit speed areas"? I think this might be what is missing.
*Thoughts?*

Thanks for reading
AH




On Wed, 20 Apr 2022 at 10:30, Graeme Fitzpatrick 
wrote:

> In regard to defaults, the default 50kph Qld (Oz-wide?) urban residential
> limit should apply around here, & sure enough, most streets are 50. But we
> also have some residential streets posted as 40, 60 & 70, as well as 40
> conditional school zones.
>
> So I assume (using that terrible word! :-)) that actually tagging a speed
> limit on a road overrides the default?
>
> & while I've seen reference to Default Qld Residential speed limit on the
> map, I've also noticed while driving around that OSMAND isn't showing a
> speed limit?
>
> Thanks
>
> Graeme
>
>
>
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Re: [talk-au] Unclassified Highway Speeds

[Graeme Fitzpatrick]

In regard to defaults, the default 50kph Qld (Oz-wide?) urban residential
limit should apply around here, & sure enough, most streets are 50. But we
also have some residential streets posted as 40, 60 & 70, as well as 40
conditional school zones.

So I assume (using that terrible word! :-)) that actually tagging a speed
limit on a road overrides the default?

& while I've seen reference to Default Qld Residential speed limit on the
map, I've also noticed while driving around that OSMAND isn't showing a
speed limit?

Thanks

Graeme
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Re: [talk-au] Unclassified Highway Speeds

[stevea]

On Apr 19, 2022, at 4:29 AM, Andrew Harvey  wrote:
> ...Otherwise I think this will always be lacking in OSM until those maxspeed 
> tags are set.

Right: this is the crux of what I was getting at. Explicit data in OSM can be 
trusted, implicitly inferring data because of "defaults," well, not so much. 
(Or, it is highly ambiguous as you might attempt to do so).
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Re: [talk-au] Unclassified Highway Speeds

[Andrew Harvey]

How about your suggestion, assigning defaults based on urban/rural, which
you may be able to roughly assign based on buffering highway=residential?

Otherwise I think this will always be lacking in OSM until those maxspeed
tags are set.

In NSW we have some open data
https://opendata.transport.nsw.gov.au/dataset/speed-zones but the usual
issues about the accuracy of that data applies, but perhaps it could be
used to fill in the blanks?

On Tue, 19 Apr 2022 at 11:54, Andrew Hughes  wrote:

> Hi All,
>
> We're using OSM and pgrouting and it's GREAT!
>
> Something that I have found difficult to come to terms with, is assigning
> a "default speed" for unclassified roads (without a maxspeed tag). This is
> because in metro area's these are most-likely to be 50kph. However, out in
> regional areas these are likely to be 100kph.
>
> *Examples:*
>
> Unclassified Roads in Brisbane: Likely to be 50kph (default)
> https://overpass-turbo.eu/s/1hLK
>
> Unclassified Roads in Yorke Peninsula Council: Likely to be 100kph
> (default)
> https://overpass-turbo.eu/s/1hLL
>
> *Question:*
>
> What would be the best approach to achieving a more realistic speed given
> the above (while also taking into consideration the tagging guidelines)?
>
> Thanks in advance
> Andrew
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Re: [talk-au] Unclassified Highway Speeds

[stevea]

On Apr 18, 2022, at 6:50 PM, Andrew Hughes  wrote:
> We're using OSM and pgrouting and it's GREAT!
> 
> Something that I have found difficult to come to terms with, is assigning a 
> "default speed" for unclassified roads (without a maxspeed tag). This is 
> because in metro area's these are most-likely to be 50kph. However, out in 
> regional areas these are likely to be 100kph.

This is an interesting “edge” that OSM seems to bump up against every now and 
then, sometimes rather public (like on a talk-list), sometimes less so, but it 
still happens.

The following is a bit fuzzy, please allow me a bit of leeway.

What I have noticed is that there are “defaults” in a legal jurisdiction for an 
activity (such as “driving through a residential zone in the state of X”) where 
that implies 40 km/hr, or 25 MPH, or some such.  What OSM seems to continue to 
struggle to do is to somehow capture this idea, whether in tagging, in wiki, in 
“understood defaults” or in some combination of the above (and/or more inputs).

While it might seem like this can be done and/or is a good idea, it can break 
down as a wider audience (of OSM downstream users / renderers / routers / use 
cases) struggles to “parse what is.”  By the latter, what I mean is that the 
combination of ambiguously “understood to apply” defaults (whether legal, in 
OSM somehow, like in a wiki, or other) become murky.  It isn’t always clear 
what to do because of what is tagged (and what might be, or isn’t, or could be) 
and understood.

Please, I urge all to be careful when we make assumptions based on “well, in 
Western Australia…” (for example) because this is a commercial zone, we can 
assume a speed limit on an unclassified road.  Sometimes it’s safe / effective 
/ realistic to assume defaults apply, much of the time it is not, and such 
assumptions are folly.  It can be difficult to even describe these, as I 
struggle for words as I type here.

So, if you’re going to do this, you have to imagine that you can imagine all 
future, downstream use-cases.  Maybe you can, maybe you can’t.  Be careful.
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[talk-au] Unclassified Highway Speeds

[Andrew Hughes]

Hi All,

We're using OSM and pgrouting and it's GREAT!

Something that I have found difficult to come to terms with, is assigning a
"default speed" for unclassified roads (without a maxspeed tag). This is
because in metro area's these are most-likely to be 50kph. However, out in
regional areas these are likely to be 100kph.

*Examples:*

Unclassified Roads in Brisbane: Likely to be 50kph (default)
https://overpass-turbo.eu/s/1hLK

Unclassified Roads in Yorke Peninsula Council: Likely to be 100kph (default)
https://overpass-turbo.eu/s/1hLL

*Question:*

What would be the best approach to achieving a more realistic speed given
the above (while also taking into consideration the tagging guidelines)?

Thanks in advance
Andrew
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