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I've been doing some work on Hanoi, Vietnam - a fair amount of incorrect roads, new but unmapped roads, and untold numbers of unmapped alleyways!

A lot of the roads inside the city are classified as primary, a few secondary, and most are residential. This seems wrong to me and generally it doesn't reflect (1) the size/lanes of the roads or (2) the patterns of traffic the roads carry.

I'd like to rethink classification of a lot of roads - make a lot of primary roads secondary, a lot of minor or residential roads tertiary or secondary - but before I do anything major, some questions:

(1) Are there any wiki resources on road classification in urban areas? I've found the following to be of some use: tagging samples/urban, key:highway, Highway:International equivalence. However, something more conceptual would help me get my head around how this would translate to Hanoi, or something more specific in terms of normal ratios of these roads (yes, I've looked at other cities to get an idea!).

(2) How aggressive should I be with making these changes? As a fairly new editor, I don't want to break any unwritten rules. If I'm going to rethink the main roads, it makes sense to change all of the primary and secondary roads within the city.

Thank you!

Note: I know the city well.

asked 30 Mar '12, 05:15

samgrahk's gravatar image

accept rate: 0%

edited 30 Mar '12, 05:17

Search on the wiki the existing guidelines about 'road tagging' (result). The wiki develops in detail how the classification works for country specific rules.
Some advices :
- classification is done by 'importance', not necessarily by physical attributs like the surface or width. A primary road might be unpaved in undeveloped countries.
- primary roads are the nation wide road network, connecting all major cities, regions and neightborhood countries;
- secondary roads network is connecting cities and towns/villages with less importance. It is more the regional network;
(from place A to place B, you should find either a single primary or a single secondary, sometimes one of each (parallel) but rarely several of the same class)
- tertiary class is the next one but still a 'network' connecting minor places e.g. between villages. Still for transit traffic.
- next one is the 'unclassified' which can be used for single destinations like an industrial or commercial zone.

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answered 30 Mar '12, 13:15

Pieren's gravatar image

accept rate: 15%

There is a Wiki page about Vietnam:

Road classification is covered there, but not much. Also, it seems a little doubtful, as "all unpaved roads should be track", which does not reflect their real significance.

As it seems that there is not yet a good classification scheme for Vietnam. Especially, not for urban areas. You can define one yourself, describe it in the Wiki (on the site I was mentioning), and then maybe contact some other users in Vietnam, if they have any objections about this scheme.

BTW: The road tagging wiki is very Europe-centered. In developed countries, there are hardly any "tertiary"-roads that are unpaved. But I guess in Vietnam, you will occasionally come across even unpaved primaries. I am tagging in Georgia, and I can tell you, the guidelines for road classification in the Wiki are merely a rough guideline, but should definitely not be followed by every single letter in less developed areas.

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answered 30 Mar '12, 07:55

moszkva%20ter's gravatar image

moszkva ter
accept rate: 17%

edited 30 Mar '12, 07:55

Thanks for that - much appreciated.

Your answer leaves me thinking that I might have to think things through carefully and developing some consistent system before jumping in and making major changes. Coming up with a classification should be a good project for the long and no-edit weekend we have coming up here in Vietnam!

You're right about developing countries: we have physically small roads in the older parts of the city that are heavily used, and huge but unused roads on the outskirts. I think I need to get up to speed on the conceptual side to know what to make of this...

(30 Mar '12, 09:52) samgrahk

don't be too "scientific" about it. Creating a scheme is easier than it sounds. If you like, you can use my road-tagging in Georgia for it and adapt it for Vietnam:

Or you might find other countries' instructions more useful.

(30 Mar '12, 13:45) moszkva ter

A classification for Vietnam's urban highways is a great idea! Having compared different maps of Vietnam I don't see any certain consensus on the highway classification in the cities (even though there are still some similarities). The truth is, there hasn't been any recognized or standard map of Vietnam yet.

I look forward to see your project on this. Maybe you can help stirring this mailing list up a bit: Vietnam mappers mailing list

I also have difficulties tagging the roads in rural areas - many of them are clearly unpaved and small but do serve as a link between towns and villages.

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answered 30 Mar '12, 11:21

LTKA's gravatar image

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question asked: 30 Mar '12, 05:15

question was seen: 11,634 times

last updated: 30 Mar '12, 13:45

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum