Changeset: 139440761
NR highways to trunk
Closed by AlkalIn
Tags
created_by | JOSM/1.5 (18746 en_GB) |
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Discussion
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Comment from cats_pajamas
Hello AlkalIn,
I am following up on my last message (https://www.openstreetmap.org/changeset/138060459) to you concerning your highway classification changes. I would like to know what criteria you are using in order to change these highways to trunk, and am curious if these changes were discussed with other members of the Africa mapping community.
I see that you have also made these classification changes in Rwanda and Burundi since my last message. Reviewing the East Africa Tagging Guidelines page on the OSM Wiki (https://wiki.openstreetmap.org/wiki/East_Africa_Tagging_Guidelines), I see that trunk highways in these countries should be paved and should have multiple lanes in a similar layout to a motorway. It would appear that many of your trunk upgrades do not match this definition. For example, you changed https://www.openstreetmap.org/way/374782511 from primary to trunk even though it is unpaved and does not have multiple lanes. Would you mind explaining why highways like this were upgraded to trunk?
I look forward to hearing from you to discuss these edits.
cats_pajamas
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Comment from AlkalIn
Hi cats_pajamas,
Sorry for the late reply.
I based this tag change on the guidline found in the wiki page of highway tags in Africa (https://wiki.openstreetmap.org/wiki/Highway_Tag_Africa). The wiki state that highway=trunk should be used for “The most important roads in a country’s system that aren’t motorways. (Need not necessarily be a divided highway.) Note that such roads can be unpaved.”Given that in these countries National Roads (RN, NR or N, depending on country) are the most important roads, then trunk should be the most apropriated tag for these. As specified in the wiki page the fact that it is undivided and unpaved does not matter. Though I undertand the concern that some (or most) of these nationals are very bad unpaved roads and it look weird that they have the same tag as large paved road in other countries. However I agree with the wiki that what matter the most is the country classification and not the state of the road.
And I might indeed have missed some discussions around these topics. Please let me know if they are specific ressources I should check.
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Comment from AlkalIn
Looking more carefully at the page you reffer to, it appear that https://wiki.openstreetmap.org/wiki/East_Africa_Tagging_Guidelines require trunk road to be paved and divided while https://wiki.openstreetmap.org/wiki/Highway_Tag_Africa (that I followed for changes in Central Africa and here in Rwanda) does not require that. It is unfortunate that Africa and East_Africa guideleines differ,
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Comment from cats_pajamas
Thank you for the response and for explaining the method you used for these changes. As you pointed out, the trunk definition on the East Africa Tagging Guidelines page does differ from the Highway Tag Africa definition. Since several of the countries you’ve made these changes in follow those guidelines (Rwanda, Uganda, Burundi), how would you feel about updating the trunk network to reflect that?
Regarding the trunk highways in countries that follow the Highway Tag Africa definition, I agree that they do not need to be paved nor divided to qualify as a trunk. However, I do think that solely basing the importance of a highway from its ref can lead to inconsistent classification. Using a couple of highways in Congo as examples, RN6 (https://www.openstreetmap.org/way/322555033 to https://www.openstreetmap.org/way/322115447, a route that is mostly just wide enough for 2 vehicles to pass, unpaved, and only connects a few small villages) and RN1 (https://www.openstreetmap.org/way/243087995 to https://www.openstreetmap.org/way/517768410, a route that is multi-lane, paved, and connects the major cities of Congo) have different levels of importance within the greater Congo highway network. This difference necessitates different classifications even though they both carry a national highway ref.
There are also many highways that I would consider simply too insignificant in both importance and infrastructure to be considered a trunk. For example, RN9 in Democratic Republic of the Congo (https://www.openstreetmap.org/way/33671087 to https://www.openstreetmap.org/way/469248644).
Something else that I would like to point out is that some African countries have their own highway classification schemes to take into consideration. For example, the WikiProject Central African Republic page (https://wiki.openstreetmap.org/wiki/WikiProject_Central_African_Republic#Road_network) notes that the most important highways in the country, those that connect the capital cities, should be tagged as primary. The OSM Africa Telegram (https://t.me/OSMAfrica) may have additional thoughts on if the RN, NR, and N refs should be classified as trunk, if you would like to open this discussion to a broader audience.
Thank you again for your response; I’m looking forward to hearing more of your thoughts on this!
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Comment from AlkalIn
Thank you cats_pajamas for the detailed feedback and the time you spend on this.
There are several ways to judge road importance: function, infrastructure and national classification. The regional and country specific pages we discussed above do clarify which one to use, as you rightly pointed out.
To follow decision made by the East Africa community and I can revert changes in ref tag I made (Rwanda, Burundi). I am not an expert in reversal procedure. But I can tag all roads currently tagged trunk in both countries, that are either not paved or not divided, into primary. Same apply for CAR. Do you agree on this, or have a better procedure to suggest?
For Congo, DRC, and other countries where no specific decision has been made, I want to point out that in https://wiki.openstreetmap.org/wiki/Key:highway it is written that "Note that highway=* distinguishes roads by function and importance rather by their physical characteristic and legal classification. Usually these things are highly correlated, but OSM is not obligated to copy official road classifications. " Which align with https://wiki.openstreetmap.org/wiki/Highway_Tag_Africa.
So, I was wrong to give priority on the national classification rather than the function. And will fix this progressively (roads like RN9 in DRC you mentioned). But I am not sure I can consider the state of the road which is often variable along the way of single roads and can be labeled with surface=* and other tags. The RN6 you mention above in Congo is a good example. RN6 plus RN3 are indeed famously unpaved and 10m wide but do function as international link between Libreville and Pointe Noire. I have not taken this road so certainly someone who visited the place can tell more about that. It means to me that we should assess status based on the function of the road (connection between major cities) to remain consistent.All the best
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Comment from cats_pajamas
Thank for you the quick response! I think your approach to changing highways in East Africa back to primary is a good one. I appreciate your input on RN6 in Congo. Since that road serves as the shortest route between those two major cities, I can see the justification to leave it classified as trunk. I also agree with your last point that highway function and importance should be the main factor when determining these classifications since the surface and condition of these roads can vary widely. I believe that this will lead to a good hierarchy of highway classification in these countries.
Thank you again for taking the time to discuss this. Happy mapping!
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Comment from AlkalIn
Thanks. I have already reverted trunk roads to primary in CAR. I will continue with Rwanda progressively.
Happy mapping as well!
- NR10 (25796123), v24
- NR10 (25796131), v8
- NR6 (25796136), v18
- NR10 (25796144), v38
- NR10 (25796168), v9
- NR10 (25796265), v12
- NR10 (25796277), v12
- Rwamagana-Kayonza Road (25796288), v30
- NR18 (25817149), v36
- NR18 (25910733), v20
- NR7 (28878956), v46
- Rubavu-Karongi (28887942), v94
- NR14 (28888866), v56
- NR18 (28891817), v25
- NR18 (28891818), v10
- NR16 (34141090), v17
- NR19 (34141096), v43
- NR19 (34141174), v38
- NR13 (101709786), v26
- NR12 (125686878), v54
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