[HOT] Introducting myself + questions about "Highway Tag Africa" standards

Sat Mar 8 17:19:02 UTC 2014

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Hi Vincent:

Since the day you sent your email, and because you talked about road
tagging in West Africa, with reference to the Trans-Sahelian Highway
(TAH 5), I thought it would be interesting to complete (took me 4 days
full time) the Trans-Sahelian and the Trans-West Coastal African
Highways (TAH 5 ( http://www.openstreetmap.org/relation/301624 ) and
TAH 7 ( http://www.openstreetmap.org/relation/301631 )), so we can
make a better analysis of them. I also created the alternate route of
the TAH 5 from Tambacounda (Sénégal) to Kati (Mali) that you referred
to: http://www.openstreetmap.org/relation/3557003

When I looked at them, they were mapped below the 10% of the whole
route, so not possible to make any interesting analysis from that. I
also included forward and backward ways in roundabouts and in highways
with separated forward/backward lanes, so we can analyse how many km
we have of separated lanes and how many of convencional roads.

For the TAH 5 (
http://ra.osmsurround.org/analyzeRelation?relationId=301624&noCache=true&_noCache=on
), we have only 0.3% motorways (inside Dakar - 12 ways and 12.54 km),
51.1% trunks (492 ways and 2,251.82 km) and 48.5% of primary roads
(221 pieces and 2,138.26 km).

As for the TAH 7, the number of different kind of roads is more
diverse. We have (
http://ra.osmsurround.org/analyzeRelation?relationId=301631&_noCache=on )
12.3% of motorway roads (most in Ivory Coast and Dakar and Lagos
cities - 80 ways and 480.08 km), 26.5% of trunk roads (234 ways and
1,031,47 km), 49.38% of primary roads (358 ways and 1936.40 km), 9.0%
of secondary roads (39 ways and 349.80 km), and 2.3% of tertiary roads
(3 ways and 89.19 km).

The TAH 5 shortcut from Tambacounda to Kita is tagged as 100% primary
road (42 ways and 696.44 km).

For the TAH 5, all the trunk roads (51.1% of total) are inside
Sénégal, Mali and Nigeria (plus the small Cameroon stretch). The
primary roads (48.5%) are inside Sénégal and Mali) and they cover the
whole path through Burkina Faso and Niger.

I wasn't involved in the discussion of the Highway Tag Africa wikipage
( http://wiki.openstreetmap.org/wiki/Highway_Tag_Africa ), but I
mainly agree with all the points there, specially about disconnecting
the hierarchical status of a road with its surface
smoothness/condition. But at the same time, I think it should be
considered as a reference, but not to be applied systematically to all
situations (if we did that, we would have to tag as primary the
motorways from Abidjan to Yamoussoukro or through Lagos and Dakar
cities, something that doesn't make any sense). In my opinion, this
tagging reference should be applied when overall conditions and
structure of the road netword in a country is at a state similar to
the one of the discussion (Mali). But nothing is written in stone,
though, and inclusion of trunk roads should be addressed one day, as
road networks are improving fast in some of the West African countries.

After traversing all those countries while creating the Trans-Sahelian
route, I would keep using the highway Africa tagging without
amendments in Burkina Faso and Niger, and I would vote to include Mali
in that tagging system too, and leave the trunk tag for when the
overall road situation in Mali improves much more. But it's not easy
to decide, I agree. Maybe we should upgrade all roads of the TAH 5
from Dakar to N'Djamena to trunk, as you suggested, and keep the rest
of the roads following the Highway Africa Tag System. But what to do
with other Trans-African highways? As for the Trans-West African
Coastal (TAH 7), there isn't even a link from Guinea-Bissau to Guinea
(Conakry) (I had to complete the link through a dirt track that
traverses some hamlets and tagged it as tertiary). And some other
roads are secondary, although I think they aren't following the
Highway Tag Africa reference (they are in Guinea Bissau and SE Sierra
Leone, two still very poorly mapped countries). Maybe that exception
of tagging as trunk all primary roads that are part of a Trans-African
highway should be applied analysing each Trans-African highway one by
one, each independently of each other.

As for the mapping of Kayes, I think it should be a good idea to
remote mapping it (and maybe those villages around it that you
referred to) before completing it on the field, at least the street
network. If you like, we can create a job in the Tasking Manager to
facilitate it. Do you want me to create one? I would help you mapping
that city.

Regards,

Rafael Ávila Coya.

On 04/03/14 03:14, Vincent Dawans wrote:
> Hello:
> 
> My name is Vincent Dawans and I am a Senior Technical Advisor at
> Virtue Ventures, a technical firm dedicated to supporting NGOs and
> social enterprises in the developing world.  As a technical
> advisor, I do a lot of traveling. I am currently traveling to West
> Africa every 3 months or so. I was last in Mali and got really
> impressed with the accuracy of the openstreetmap layer (I was using
> the MapWithMe android app that gets its data from openstreetmap);
> certainly the level of details in Bamako is quite impressive,
> enough that I was able to go on long walks through the back streets
> without ever getting lost.  Seeing all that good work got me
> interested in getting involved.
> 
> One of the organizations I work with is a village-banking
> organization around Kayes (Western Mali) and my plan is to give
> them gps receivers so they can start mapping the many villages in
> which they work. I got some old $25 gps receivers online that I
> will try using for that purpose...
> 
> I also stared updating the map for Kayes itself (it needs some 
> attention).  However as I am looking at the "Highway Tag Africa" 
> standards I am a bit confused as to the lack of mention of the 
> "highway=trunk" and "highway=motorway" tags.
> 
> I am going to take West Africa as an example since this is what I
> know. I feel like the main regional roads should be consistently
> marked as "trunk" and not merely "primary".  Right now some
> sections are marked trunk, other primary. By "regional roads" I
> mean mostly the roads that are part of the new Trans-African
> Highway Network that is taking shape. The Trans-African Highway
> Network comprises a series of east/west and north/south roads
> crossing the continent. Here is a good overview of the 
> Trans-African Highway Network: 
> http://en.wikipedia.org/wiki/Trans-African_Highway_network
> 
> My personal experience with that network is the Trans-Sahelian
> Highway (Trans-African Highway 5), more specifically its first
> section running from Dakar to Ouagadougou which I use on a regular
> basis. http://en.wikipedia.org/wiki/Dakar-Ndjamena_Highway.  The
> section running from Dakar to Ouagadougou actually splits into 2
> branches from Tambacounda, Senegal to Kita, Mali (one branch is the
> original northern road via Kayes Mali, and the other one is the
> brand new southern road via Kenieba and Kati, Mali.).
> 
> I feel that these roads would benefit from being more consistently
>  "upgraded" from primary to trunk because they are not only
> important roads for their respective countries but are in fact
> becoming the backbone of the road network in their respective
> regions and serve as the primary roads crisscrossing the continent.
> IMHO they fit the official trunk definition of "The most important
> roads in a country's system that aren't motorways."
> 
> Whatever decision is made, some clarification is necessary because
> right now some sections of that network are already marked as trunk
> on the map, but in a very inconsistent manner, with some trunk
> roads becoming primary mid way without reflecting actual changes on
> the ground. Here is just one example for illustration purpose: in
> Senegal the trunk tag starts in Kaffrine and ends in Kotiari, then
> it becomes trunk once more in Mali between Segala and Bamako. In
> reality there is no reason why the Dakar-Kaffrine section and
> Tambacounda-Segala section should not be marked as trunk as well --
> or all of it marked as primary; but not a mix of both...
> 
> Additionally, the highway=motorway tag also needs to be clarified;
> on the map, motorways are already found, mostly in Northern and
> Southern Africa with some also starting to show up in East and West
> Africa. For instance right now there is a short motorway running
> from Dakar to Rufisque-- it's a real motorway, a restricted access
> road build as per international standards -- a first in West Africa
> I think.
> 
> Hence I think the "Highway Tag Africa" guidelines would benefit
> from being expanded with trunk roads and motorway; if nothing to
> clarify the current mixed used of motorway, trunk and primary tags.
> I would love to know what the opinion of the community is on this
> matter. I am willing to help draft some changes to the guidelines
> if there is some buy-in for the general idea presented here.
> 
> I am new to this mailing list and community, so I apologize if this
> was discussed earlier or if I am not fully informed about the
> issue. Thank you for reading my long (too long) email.
> 
> Sincerely,
> 
> Vincent Dawans
> 
> 
> 
> _______________________________________________ HOT mailing list 
> HOT at openstreetmap.org https://lists.openstreetmap.org/listinfo/hot
> 

- -- 
Twitter: http://twitter.com/ravilacoya

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Por favor, non me envíe documentos con extensións .doc, .docx, .xls,
.xlsx, .ppt, .pptx, aínda podendoo facer,  non os abro.

Atendendo á lexislación vixente, empregue formatos estándares e abertos.

http://es.wikipedia.org/wiki/OpenDocument#Tipos_de_ficheros
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