[talk-au] Back in editing - Tracks and 4wd areas

Matt White mattwhite at iinet.com.au
Sun Jan 15 09:33:55 GMT 2012


OK, so I'm a bit late in the game on this one, but I've just come back 
from mapping some 4WD tracks around Mt Stirling, and I thought I'd throw 
in my 2 cents here (also, the 4WD_Only tag is the one and only tag I've 
ever proposed in OSM, so I have a sentimental attachment to it).

If a track seems to be 2WD for a bit, and then 4WD for a bit, then back 
to 2WD (and so on), then the entire section between other track 
junctions really does need to be marked as 4WD.

Eg:

    Section A     Sec B     Sec C      Sec D      Sec E
      2WD 2WD       4WD        2WD         2WD
---------------|--------=============---------|---------------------------------- 
road A
                |             |
                | road B:2WD                 | road C:2WD
                |             |
                |               |
                |
                |


So, if you are travelling on road A, and there is a section of 4WD in 
there, then instead of marking just that section as 4WD, then entire 
road between the junctions (ie: sections B, C and D) would need to be 
marked as 4WD, while sections A and E could remain as not marked for 4WD 
access.

It's all very well to say only mark the section that is 4WD, but from a 
routing perspective, it's pretty important that you don't end up in a 
2WD vehicle stuck (ie: sections B and D might be 2WD navigable with a 
bit of effort going forward, but if there's no place to turn around, 
then trying to navigate them while driving in reverse gear could end in 
serious tears (especially if the area is remote, there are some steep 
ascents/descents, the weather turns nasty etc.)

As for the signage/marking of tracks, DSE and Parks Victoria are 
trialling a new track classification system for 4WD tracks. There are 
only a handful of roads in the state that have been classified so far, 
but rather than just having 4WD-only=yes, we might also be able to tag 
the roads with their classification (there are four categories, easy, 
medium, difficult and very difficult - see 
http://parkweb.vic.gov.au/__data/assets/pdf_file/0006/318768/4WD_Recreational_Track_Classification.pdf). 
Parks Vic are apparently going to start signing the tracks with these 
classifications apparently, so we might need to work up some tagging 
structures for this I guess (I think I spotted one at the base of the 
track to Craigs Hut, but not sure).

There's also an interactive (but pretty slow to load) map 
http://nremap-sc.nre.vic.gov.au/MapShare.v2/imf.jsp?site=forestexplorer 
that shows the 4WD trails they have trialled the classification, which 
gives you a better idea of what I mean (turn on the Recreation/Four 
Wheel Driving layers)

Matt




On 5/01/2012 10:11 PM, Ross Scanlon wrote:
> On 05/01/12 18:47, Sam Couter wrote:
>> Ross Scanlon<info at 4x4falcon.com>  wrote:
>>> To me this is really odd.  If the track is 30km long and there is
>>> 1km of 4wd only then is not this track all 4wd_only.  As without a
>>> 4wd you will not be able to go from one end to the other in a 2wd.
>>
>> Only if the track has no other access. Said access may not yet be mapped
>> in OSM. 2WD can also be used to get from one end of the track to the 4WD
>> section, even if it can't be used to traverse the 4WD section.
>
> Ok so if your mapping every 10m and the first 10m is 2wd and then the 
> next is 4wd the remainder of the track becomes 4wd_only.
>
> Read the wiki:
>
> http://wiki.openstreetmap.org/wiki/Tag:4wd_only%3Dyes
>
> It's quite specific as to what constitutes a 4wd.
>
> And all your's below has been discussed before.
>
>
>
> Cheers
> Ross
>
>
>>> Also any track sign posted as 4wd only should be marked in it's
>>> entirety as 4wd_only=yes.
>>
>> What's the difference between "NPWS sign states 4WD only" (You can be
>> fined real money for disobeying these signs), "You'd be crazy to drive
>> a Commodore down here" and "Holy shit, how'd that Commodore get here?!".
>>
>> The tagging guidelines page isn't clear about this and people in general
>> have no idea about how far you can really drive a 2WD if you're
>> determined and skilled. Conversely, people in general have no idea how
>> easy it is to get stuck in a 4WD if you are not skilled.
>>
>> Also, contrast tricked-out Toyota Landcruiser with Subaru Forester with
>> 2WD rally car. These vehicles, ignoring driver skill, have vastly
>> differing off-road capabilities. The 2WD rally car will go places the
>> 4WD Forester won't. Clearly the Forester isn't a serious 4WD like the
>> Landcruiser, but the rally car isn't 4WD at all. How to indicate that
>> the Forester isn't suitable for a particular track?
>>
>> The 4wd_only tag lacks any of the expressiveness needed to solve the
>> problem and the tagging guidelines don't address it either.
>>
>>
>>
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