OpenStreetMap

Dealing with incorrect tags in Africa

Posted by NicEd on 17 November 2015 in English (English)

So today I spent quite some time correcting tags of three major roads in Luanda ANG, Kitwe/Ndola ZAM and Windhoek NAM. The three roads were tagged as freeways.

While they may kind of look like freeways, nowhere along the extension of these roads is there proper signage identifying them as such; the T3 dual carriageway from Ndola to Kitwe has many 60km/h limit zones, which automatically takes the right from that road being called a freeway.

The Windhoek B1 Western Bypass has all the structure to be tagged as freeway; however, freeway signs in Southern Africa are blue (K53 code); B1 has all its signage in green. Often authorities refrain from taking that step so that slower traffic is not restricted from using the road under the access restrictions that apply to motorways. This is the case for Windhoek.

The unnumbered road in Luanda is de facto an expressway, and it actually carries the name in Portuguese, which is Via Expressa. Also, the very intricate road configuration in Angola makes it rather difficult to always tag roads correctly, since the passing (inner) lane is also the exit lane to U-turns and other road links, which exist in a great number on most primary roads in Luanda and other cities. Non-observed speed limits range from 30km/h to 90km/h, so this factor alone doesn't allow any of these roads to be tagged as freeways.

To the taggers who were there before me. Please understand that I corrected all your tags (about 200 of them), and this alone would possibly trigger an edit war; I strongly discourage you from doing so. If you have any enquiry about the last edits of mine, please drop a comment on this entry, or PM me.

Comment from Warin61 on 17 November 2015 at 23:31

While you maybe 'correct' in an absolute sense complying with the OSM definitions ...

There is the consideration that these definitions were worked out by people in very well developed and rich countries with high population densities of well off people. That is not the case in Africa. The 'importance' of the road may not be reflected in the number of lanes, surface, smoothness or as you have stated in its official classification. Thus the official 'OSM classification' can be inappropriate in some circumstances.

Further reading ... http://wiki.openstreetmap.org/wiki/Highway_Tag_Africa

I would suggest you contact at least some of the previous mappers to get their views directly.

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Comment from joost schouppe on 28 November 2015 at 08:25

The Highway Tag Africa is highly relevant, however it does not talk about freeways. If there is any type of road we could agree on at a global level, it should be freeways. There is a simple list of physical properties that you can use to decide if it is a freeway or not.

For all other road levels this is much more complex. The African scheme takes into account only economic/practical importance measures, but in countries like Peru and Argentina the government classification has final say.

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Comment from joost schouppe on 28 November 2015 at 08:27

So to second Warin: don't just "correct wrong tagging", but get involved in local road tagging discussions. Otherwise you run the risk of getting your work reverted.

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Comment from Janjko on 28 November 2015 at 18:50

Highways are just the highest step in road clasification. That tag shouldn't describe physical properties of a road, that's the job for specialized tags.

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