Eric
These discussions show us that it is not an easy job to classify roads. The
governments classify roads for administrative purposes and this do not
necessarily show a clear hierarchy of roads. We may use
partly this classification, but we have to adapt it to show a clear
hierarchy of roads.
The ideal situation would probably be if we could make spatial analysis taking
into account the population of each populated place. But often, we do not have
such information and should adopt a pragmatic approach.
Pierre
>________________________________
> De : Eric SIBERT <courr...@eric.sibert.fr>
>À : hot@openstreetmap.org
>Envoyé le : Dimanche 24 mars 2013 17h01
>Objet : Re: [HOT] Fwd: Re: New Job for Tracing in the Congo
>
>In Madagascar, there is also a governmental road classification.
>
>http://wiki.openstreetmap.org/wiki/FR:WikiProject_Madagascar#Hi.C3.A9rarchisation
>
>http://www.lalana.org/documents/reglementations/routes/decret_99_976%20RN.pdf
>
>National Roads are divided in three groups:
>- primary : joining provincial prefecture
>- secondary
>- tertiary and/or temporary (maintained by regional authorities)
>
>General recommendations for OSM are :
>- more secondary than primary
>- more tertiary than secondary
>- unclassified+residential : more than 50% of the roads
>
>At this point, in Africa, you face a first problem: where is the limit between
>roads and tracks?
>
>From malagasy government :
>- primary : 2560 km
>- secondary : 4630 km
>- tertiary : 4550 km
>
>Total including regional and local.. roads : 38 000 km.
>
>My first idea was to use the governmental classification. But the ratio
>between secondary and tertiary was not good. So my suggestion is to add the
>roads going to the main village of each "commune" from the national network. I
>don't have any idea on how much the length is. But with 5000 km, this would
>fulfill all the conditions mentioned above.
>
>All of this don't tell where are the roads. So, I spent a lot of time
>crowdsourcing to find the locations of the roads. With Bing and the help of
>several contributors, it was possible to draw must of them.
>
>Now, back to RDC.
>
>Routes Nationales (19 605,73 km soit 35,5% du RRIG)
>Routes Prov. prioritaires (19 715,18 km soit 35,7% du RRIG)
>Routes Prov. secondaires (15 918,28 km soit 28,8 % du RRIG)
>
>The first idea would be to use them as primary, secondary and tertiary
>respectively. But the ratios are not good. Are national roads really better
>than provincial ones? Are some national roads more important? The ones part of
>"Corridors Régionaux"? Any data or local knowledges are welcome.
>
>
>Éric
>
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