[OSM-dev] Renderer issue: highway=service and service=driveway?

[Mark Newnham]

Pierre,

As a European mapper based in the USA, I'd just like to add my support here to what you are saying, and hope to clarify a little bit. 

I think the methodology described in the Wiki for mapping highway tags is very much based on a 'Euro-centric' approach -  The relationship between the quality of the road and it's importance is implicit, and certainly from where I originate from, the UK, there is nowhere that a normal person can get to without travelling a well-maintained, paved road. 

Its often difficult for a European to imagine that important roads can be terrible. It's surprising to learn, for example, that more than 50% of public roads here in Colorado are unpaved, and subject to many of the issues, such as bridge wash-outs, impassibility when wet etc,  that simply do not occur in Europe. 

Putting this into context, in the Wiki, the description for a secondary road is:

Administrative classification in the UK, generally linking smaller towns and villages



and the description for a tertiary road is: 

 A "C' road in the UK. Generally for use on roads wider than 4 metres (13') in width, and for faster/wider minor roads that aren't A or B roads. In the UK, they tend to have dashed lines down the middle, whereas unclassified roads don't.


Here in Colorado, outside of urban areas, i.e. 95% of the state,  whilst every town might be served by 2 paved secondary roads (generally north-south / east-west), any cross-connectors would be a tertiary road, but would likely be unpaved.  Use of these tertiary roads might save 100's of kilometers in travel distance, so they must be mapped as tertiary so that mapping and routing software can use them correctly, even though they absolutely don't match the Wiki criteria for that road type

I recognize that this issue is even more distinct in Africa, where even primary roads may meet the Wiki Criteria for "highway=track / tracktype=grade5/smoothness=catastrophic". 

My solution for the Wiki:

	1. Eliminate any reference to a road standard in a particular country (if necessary branch it off to a country-specific page)
	2. Eliminate any reference to the quality of the road surface (if necessary branch it off to a country-specific page)
	3. Keep the definition for Motorway - this is pretty much the definition worldwide
	4. Below that, define each type of road by the importance of  the route. Criteria could be, for example, population of city served, length of route, whether any reasonable alternative routes exist.

e.g. road definitions could be simply:

Primary: A road that is connected to a population center of at least 100000 inhabitants, or is connected to a seat of government, or is at least 200km long

Secondary:  A road that is connected to a population center of at least 10000 inhabitants, or is at least 100km long, or connects a primary road to another public road 
Tertiary: A road that is connected to a population center of at least 1000 inhabitants, or is at least 50km long, or connects a secondary road to another public road

etc, etc

I think it's important to make OSM  definitions usable and consistent worldwide, and this one is really important

Regards

Mark




________________________________
 From: Pierre Béland <pierzenh at yahoo.fr>
To: Martin Koppenhoefer <dieterdreist at gmail.com> 
Cc: "dev at openstreetmap.org" <dev at openstreetmap.org> 
Sent: Wednesday, January 8, 2014 7:58 AM
Subject: Re: [OSM-dev] Renderer issue: highway=service and service=driveway?
 


Martin 

The images in the Highway tag usage wiki page give implicitely instructions to take care of the quality of the road to classify. But it is stated at the beginning of the page, that it is sometimes useful to adapt highway tag usage to the local physical conditions. And this is the case for many countries from the south where road conditions are quite different from what we expect in countries from the north.

While mapping for Mali, we were confronted with mappers not able to classify properly the roads. Too many were identified as tracks. In fact, we have to think differently from countries of the north. For 
example, north of Mali, you have major roads not paved and badly 
damaged at the rainy season. They are still major roads and should be 
classified this way.

The Highway_Tag_Africa page insist on a simple hierarchy to classify the roads.  We make a clear distinction between the hierarchy and the condition of the road. Other tags are used to take care of the surface and road conditions. In later discussions on the HOT list, people suggested that this apply to a majority of countries from the south. In fact, we often have roads badly classified. People working for HOT activations agree in general that these rules are adapted to the context of the countries were we work.


 
Pierre 



________________________________
 De : Martin Koppenhoefer <dieterdreist at gmail.com>
À : Pierre Béland <pierzenh at yahoo.fr> 
Cc : Greg Troxel <gdt at ir.bbn.com>; "dev at openstreetmap.org" <dev at openstreetmap.org> 
Envoyé le : Mercredi 8 janvier 2014 7h30
Objet : Re: [OSM-dev] Renderer issue: highway=service and service=driveway?
 




2014/1/8 Pierre Béland <pierzenh at yahoo.fr>

In this particular case, if there was a hierarchy of roads, it would be less a problem if the rule that I proposed was followed. See https://wiki.openstreetmap.org/wiki/Highway_Tag_Africa

I don't understand this page. Not that I had objections with what I read there, but it is a duplication of what is already set. Why "Africa"? We should have (and do have) a global system to tag and classify roads, bridge=yes and layer=1 are nothing special to Africa, neither is a hierarchical road system. My suggestion is to delete the page or link to the specific pages in to keep the wiki maintainable. Duplicating the same information over and over again has no sense and raises the risk for inconsistencies.


cheers,

Martin



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