[Talk-lt] secondary/tertiary in proposed definitions at WikiProject Lithuania

[Mateusz Konieczny]

7 cze 2022, 13:54 od tomasstraupis at gmail.com:

> 2022-06-07, an, 14:24 Mateusz Konieczny via Talk-lt rašė:
>
>> It seems to have no benefits whatsoever and is problematic from cartographic,
>> consistency, QA and other perspectives.
>>
>
> Well, since you claim you have knowledge in cartography, can you
> elaborate on which cartographic rules is this breaking? 
>
For start I want to note that paved/unpaved distinction can be more
important that general road importance for some purposes 
- but in such case surface=* data would be used and shown

And yes, you can get rid of some bad effects by automatically fixing
invalid data (degrading isolated highway=secondary to highway=tertiary)
- but having bunch of such rules for each region is obnoxious and pointless
where classification was simply badly done in the first place.

It is also, obviously, causing cartographic issues only when secondary and
tertiary roads are shown differently.

But in cases where there is attempt to use highway=secondary/tertiary
according to its purpose (overall importance in road network) then having
such short sections is problematic at least for following reasons:

- reduced map legibility for no benefit
- losing ability to show road network properly without preprocessing that would
remove bad classification (obvious example is attempt to show only highway=secondary
and more important roads that will give you also random segments of paved
highway=tertiary)
- highly unusual abberation (in case of maps on scale larger than Lithuania)
- road importance in road network is not changing in this case, this
data is outright false
- confusing for no good reason

It makes much harder (but not impossible) to have well done maps that
show (among other things) general road importance

> Given that
> paved and unpaved segments have actually different rules/procedures of
> maintenance - therefore such depiction is actually communicating
> correct and important information to the map reader.
>
if someone wants to show paved/unpaved status then they should use
surface=* tags, not mistag road importance and force render to show
paved/unpaved status despite that it attempts to show overal road 
imprtance ( https://wiki.openstreetmap.org/w/index.php?title=Mistagging_for_the_renderer )

>  Also what specific QA problems does this raise? Can you provide some examples?
>
Disjointed road classes are serious problem and reported by QA
capable of analysing road network graphs, in Lithuania this reports
are harder to process and distinguish from tagging sadly treated as OK.

>  We have some small stretches of motorway being marked by official
> signs as not a motorway (for one reason or another but with real
> influence on maxspeed, permissions etc.), would you also suggest
> ignore the physical reality and tag those parts as motorway anyway
> just for the sake of continuity?
>
Not sure, would need to be more familiar with specific cases
and I would say "it depends".

But some cases known to me involved nonmotorway section with
traffic lights, sharp turns etc. In such case it should not be marked 
as motorway.

I also heard about cases where motorway was not officialy motorway
for only political reasons - in such case it likely should be highway=motorway

> P.S. Sometimes roads do change their state/appearance drastically on
> the borders. Besides, which country should be less important and
> change their classification?
>
Ideally it would be discussed and some agreement reached.
And in general, road importance is not changing much.
State/appearance is correlated with=* and rigid classification
of highway=* based on road quality is a mistake
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