> 4 lane ‘tertiary" road that handles 5 times the vehicle traffic, traveling on to connect with 2 major trunk roads - > intersects the narrow two lane “secondary road” that is one of the small roads coming down from the “suburbs” into the city
Interesting. I was unaware about so drastic changes in meaning of tag by editors. This one cripples Japanese road data - and I am unsure what could be done about it. 2015-01-15 9:13 GMT+01:00 johnw <jo...@mac.com>: > I’m a newcomer, and somewhat of a noob, But I’ll take a crack at it.: > > ** We are drawing existence, and tagging purpose, usage, and metadata - > with a varying balance of importance between those 3 things. ** > > There are some caveats - it needs to stay put for a long time, and it > needs to be such a size that a point, way, area, or relation can be used to > accurately enough describe it’s existence (tagging poodles is out of the > question, unfortunately, and a point cannot accurately define a road). > > A road exists, and we then tag what purpose the road has. It’s usage and > construction informs it’s classification and descriptor tags, and it’s > name, ref and other metadata are tagged, along with it’s meta-meta data of > what system the road belongs to in a larger context (relations). > > usually for man-made features, what exists is there because it’s purpose > is why it exists. Things get fuzzy in edge cases when something is reused > (eg: a business in an old church building), but so many things are fragile > enough that disuse means destruction and repurposing of the land - or its > current disuse and decay are the tags to use when showing that it exists > (for the time being). > > Trouble arises since we all should use the same tag values and > definitions, which is somewhat impossible because taggers are tagging the > world as they feel it exists (and what purpose it has), and at the detail > level they are comfortable or familiar with, which gives rise to issues > between taggers, and between regions, as people from different regions see > the world and define their world a bit differently. > > an overly long example: > > For example, here in Japan, they have a relatively rigid definition in OSM > of what a primary and secondary road are - which in many cases has > absolutely nothing to do with construction or usage. for the most part, > they have no bearing to if they are truly primary or secondary roads, but > if they are legally a certain type of road for political reasons (who > maintains them, who owns them) - in some cases they are old, narrow, and > meandering roads that used to be a major route (100 years ago) - but are > now bypassed by newer and newer “bypass" roads meant exclusively for cars, > with modern standards (like I would find in California). Most bypass roads > are considered “tertiary” - only because they are not in the same legal > classification as the older, more “important” roads - though they are > better in almost every single measurable way than the road they are > bypassing. > > There is a “primary” road near my house that is thinner than many alleys > (less than 2.5m in one spot) , has an awkward level crossing impassible by > trucks, bridged over by the trunk road (it doesn’t connect), and I wouldn’t > recommend using it for any reason. The nearby “tertiary” and secondary > roads are a superior choice - and connect to the trunk roads - and even > have painted center line(!) - the OSM:JA definition of a tertiary road - > which doesn’t apply to the secondary or primary roads. > > Similarly, Large primary roads legally take turns at intersections (they > are almost never straight inside a city), and even though the road itself > continues on straight in an identical manner (lanes, width, traffic, > standards, etc), it becomes a tertiary road - and then intersects with > several narrow, underused secondary roads! The larger, 4 lane ‘tertiary" > road that handles 5 times the vehicle traffic, traveling on to connect with > 2 major trunk roads - intersects the narrow two lane “secondary road” > that is one of the small roads coming down from the “suburbs” into the city. > > But this is the way Japanese people *expect* their maps to be portrayed, > so I have to accept that this balance of metadata (the ref # on the sign) > is more important to them than usage when it comes to road classification > above unclassified. > > In other places, the primary road I mentioned would be classified as an > “unclassified” road, and the tertiary as a primary - but it is inconsistent > with what Japanese mappers expect, so “shoganai” - it can’t be helped. > > > Figuring out this *balance* between purpose, usage, and metadata is a > difficult, almost impossible task - not to mention how to organize the tags > in a human usable and machine parseable manner (go-go tagging mailing > list!), but the sentence seems to encapsulate OSM pretty well. : > > ** We are drawing existence, and tagging purpose, usage, and metadata - > with a varying balance of importance between those 3 things. ** > > Javbw. > > > > On Jan 14, 2015, at 9:28 AM, Warin <61sundow...@gmail.com> wrote: > > > > This comes from the tap discussion but has implications elsewhere. > > > > What is the basic philosophy of OSM tagging at the top level? > > > > Are 'we' tagging for > > > > What things are? eg highways > > > > OR > > > > What things are used for? eg amenity > > > > ---------------------------- > > Explanation? By example; > > > > Highways are used for transport so would be better tagged as > transport=motorway, sub tags for vehicles etc. > > > > OR > > > > amenity=drinking_water would be better tagged as water=blubber > > > > -------------------------- > > Is there an FAQ on this? Or has this never been documented/though of? > > Have fun with this :) > > > > > > > > > > _______________________________________________ > > Tagging mailing list > > Tagging@openstreetmap.org > > https://lists.openstreetmap.org/listinfo/tagging > > > _______________________________________________ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging >
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