Re: [Talk-us] highway: tertiary?
David Carmean wrote: > I'm not sure if this question is within scope of this list, but > I thought it might be sufficiently country-specific: when is it > appropriate to use "highway: tertiary" in the US? I use it like so: tertiary - through residential areas: two-lanes, maybe with street parking but often not, lanes delineated by yellow lines (in lesser populated areas, often no shoulder). Through commercial areas: storefronts usually face away from these two-lane streets - they feel like a bypass, u-turn route or only there to get to 'parking out back' lots. Often called 'back-streets' or 'minor arterials'. In my area, they are often delineated further by 'arterial route' signage. ___ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
Re: [Talk-us] highway: tertiary?
Here's an example, where I used to live a short distance south of Alviso: http://www.openstreetmap.com/?lat=37.3851&lon=-121.9258&zoom=14&layers=B000FTF See the light yellow roads that connect to other roads such as Montague Expressway and 1st St? Roads such as Lick Mill Blvd, Orchard Parkway, Plumeria? They're actually fair wide roads, and can have ~40 mph speed limits. The thing is, they're used only by people getting to local homes or businesses - they're not the main through routes. For San Jose, I've mentally come up with a system that's goes like this: Motorways are any and all limited access freeways - Highway 87, US 101, I-280 Primary highways are "Expressways" - or the few other roads that are similarly important. Montague Expressway, Lawrence Expressway, San Tomas Expressway, El Camino Real, Stevens Creek Boulevard: the heavy duty arterials. Secondary Highways are those roads you may take for a few miles, but are a little less important - such as Lafayette Street (which turns into Gold Street in Alviso - I wonder if I should have demoted it to a tertiary highway after it crossed under 237.) And then you have your tertiary roads. I've been subjective enough about this that I don't mind if some of these roads get reassigned, particularly in some neighborhoods I'm less familiar with. The San Jose map was in desperate need of having some sort of hierarchy of importance, so some areas I was less familiar with - such as East San Jose - I've tried to pick out the primary and secondary roads, without assigning tertiary roads. But hopefully, when you look at the map, you can quickly decide: what are the main roads I'd used to get to a neighborhood? What are the main roads within a neighborhood? That's another way to think of secondary and tertiary roads. -Alan - Original Message From: David Carmean <[EMAIL PROTECTED]> To: Alan Brown <[EMAIL PROTECTED]> Cc: talk-us@openstreetmap.org Sent: Sunday, September 14, 2008 12:11:42 AM Subject: Re: [Talk-us] highway: tertiary? Alan, I live in the Bay Area and in fact will probably be augmenting some of your work down around Alviso and Sunnyvale; do you have any examples where you've actually chosen to use highway=tertiary? On Sat, Sep 13, 2008 at 09:57:52AM -0700, Alan Brown wrote: > I noticed the following suggested definitions for California for different > road classes: > > http://wiki.openstreetmap.org/index.php/California > > > For tertiary, they suggested > > > highway=tertiary > Lower traffic volumes on wide streets, or higher on narrow ones. > > > Kinda' vague and I'm not sure I'm in agreement with these definitions, > personally. I'd be even more vague :) . Here's what I think as someone who > worked in a map data company for a decade: > > ___ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us ___ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
Re: [Talk-us] highway: tertiary?
Alan, I live in the Bay Area and in fact will probably be augmenting some of your work down around Alviso and Sunnyvale; do you have any examples where you've actually chosen to use highway=tertiary? On Sat, Sep 13, 2008 at 09:57:52AM -0700, Alan Brown wrote: > I noticed the following suggested definitions for California for different > road classes: > > http://wiki.openstreetmap.org/index.php/California > > > For tertiary, they suggested > > > highway=tertiary > Lower traffic volumes on wide streets, or higher on narrow ones. > > > Kinda' vague and I'm not sure I'm in agreement with these definitions, > personally. I'd be even more vague :) . Here's what I think as someone who > worked in a map data company for a decade: > > ___ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
Re: [Talk-us] highway: tertiary?
I noticed the following suggested definitions for California for different road classes: http://wiki.openstreetmap.org/index.php/California For tertiary, they suggested highway=tertiary Lower traffic volumes on wide streets, or higher on narrow ones. Kinda' vague and I'm not sure I'm in agreement with these definitions, personally. I'd be even more vague :) . Here's what I think as someone who worked in a map data company for a decade: Navteq and Tele Atlas have something known as a "functional road class" that is used to designate the relative importance of a road for getting to your destination. During a typical trip, you would progress from roads of less-important functional road class, to more-important fucntional road class, and back down to less-important functional road class as you reach your destination. I would guess, within a mile of most urban origins, you'd expect to be on a "tertiary" road, and within another mile you'd find yourself on "secondary" road, and so forth. (Of course, if you can get to a more important road quicker, you'd use that.) Point to be made is, the functional road classification of a road might not strictly reflect the physical attributes of the road (number of lanes, speed limit, etc.) but rather, the relative importance of a road in its particular vicinity. The clearest example of this I can think of is the Transcanadian Highway. There are portions of the Transcanadian Highway that are not limited access, due to low population densities. However, Navteq gives it the "most important" classification level - while some Interstate Freeways, and many local limited access freeways in the US, are not assigned to that category. Point to made is, commercial data providers are somewhat subjective in their assignment of "functional road class". Open Street Map's "Highway" attribute may be a bit different: certainly, a "Motorway" is a clearly defined type of road. However, when I've assigned "Primary", "Secondary", or "Tertiary" categories, I've tried to use local knowledge to reflect what the relative importance of those roads are. It will tend to track the physical attributes of the road, but not strictly. Some of it's aesthetics - I'll try to decide which primary roads should be demoted to secondary roads if the map starts looking too cluttered, or try to promote some roads from tertiary to secondary if the map looks too thin. Perhaps one secondary road between each pair of primary roads, and one tertiary road between each pair of secondary roads (although that's impossible to it exactly like that.) San Jose (where I live) has a lot of physically wide roads with moderately high speed limits that aren't used nearly as much as other roads with the same characteristics. Use the highway attribute to reflect that reality. Use explicit attributes to define number of lanes and speed limit. It's subjective. A Tele Atlas map and a Navteq map based on functional road types will look different because they made different judgements. (They do have rules to eliminate some of the subjectivity - but not completely.) That's my opinion - anyone disagree? - Original Message From: David Carmean <[EMAIL PROTECTED]> To: talk-us@openstreetmap.org Sent: Saturday, September 13, 2008 9:48:35 PM Subject: [Talk-us] highway: tertiary? Hi, I'm not sure if this question is within scope of this list, but I thought it might be sufficiently country-specific: when is it appropriate to use "highway: tertiary" in the US? Thanks. ___ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us ___ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
[Talk-us] highway: tertiary?
Hi, I'm not sure if this question is within scope of this list, but I thought it might be sufficiently country-specific: when is it appropriate to use "highway: tertiary" in the US? Thanks. ___ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us