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#1 2018-04-26 22:40:14

stephankn
Moderator
Registered: 2010-05-04
Posts: 606

Rural roads ref numbers

Hi,

I did not use the website but only my photo mapping. But as someone mentioned it a being a usable source: Is it also reliable?

I recently saw this change:
https://www.openstreetmap.org/changeset/58234217

A Facebook edit was enhanced with some ref numbers and a way upgraded to tertiary.

The aerial imagery give no indication of this road being upgraded. No GPS tracks and no up to date imagery.

All is indicating the way 535043410 is at most a residential, probably more a agricultural road.

How should we deal with the http://lmp.drr.go.th/gisLmp/ source?
Based on this it seems to me the quality is very low and should not be used to re-classify existing roads.

Any thoughts? Can someone provide recent street level imagery of the mentioned way?

Stephan

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#2 2018-04-27 03:31:42

Russ McD
Member
From: Hereford & Chiang Mai.
Registered: 2011-04-17
Posts: 289

Re: Rural roads ref numbers

I think the best way to consider the local roads website, is as yet another tool in our armoury.  My thoughts are that if a Rural road appears on there, where no information previously existed, then its probably correct.  It may be, and probably applies to the changeset above, is that while the road is now listed as a rural road, any physical improvements may come at a later date.  Whether we tag on physical appearance is another issue.

In this changeset, I noted some new RR signs & paved roads while riding down the 1184.  Naturally I did not have the time to ride down every one so I referred to lmp.drr.go.th before plotting, as it helps with the length of RR from the main Hwy.  In this case it drew my attention to the fact that there were a number of new Rural Roads in this area, and from our outdated aerials, I could see that many previously plotted tracks, were now 2 lane asphalted roads, carrying a RR ref. 

While I accept that after checking Google streetview, the one way mentioned does look like a residential road, I chose to use the info on the database, and per our Wiki, gave it a Tertiary status.

Seeing a new sign physically on the road, supersedes the database in my mind, but there will always be exceptions as Alaska Dave and I remember a road in Udon that carried different numbers on the blue signs, as were on the mileposts ... for at least 2 years !

However, by way of example, yesterday I added the South Western section of the new Chiang Rai bypass. https://www.openstreetmap.org/changeset … 83/99.7940

This a major 4 lane dual carriageway and is now open for traffic, but you won't find any evidence of it on the rural roads database, or roadnet !  It's mostly farmland on all the aerials we are allowed to use.  Only Google satellite carries evidence of its construction, (and has it plotted as a road too).... but we can't use their images & data, right ?

So I think I can confidently say that the two "official" road databases are not current and continually updated, which may go some way to answering Stephan.

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#3 2018-04-29 18:23:43

Bernhard Hiller
Member
Registered: 2011-05-10
Posts: 1,044

Re: Rural roads ref numbers

Knowing ref numbers of roads is good: they help for orientation, and provide a first hint on classification.
https://wiki.openstreetmap.org/wiki/Key:highway lists the road types "from most important (motorway) to least important (service)". I.e. their importance is the major criterion for classification.
In case of ลพ.4064, the road is more likely an "unclassified".
In contrast, the Chiang Rai bypass was built for large traffic and high speeds at a "trunk" standard. Since (currently) it ends in nowhere in the east, "trunk" is not applicable. But I think "secondary" could be a better fit than "tertiary". And a re-tagging when the bypass gets extended.
Also ชร.5023: how important is that road? And how important is road #1 there still?
I do not know that area, that information must be supplied by people with knowledge of that place.

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#4 2018-05-01 12:39:11

Paul_012
Member
Registered: 2011-08-05
Posts: 210

Re: Rural roads ref numbers

Eh. The site is currently down, so I can't exactly tell what we're supposed to be seeing. But cross-checking with the PDF reports at http://maintenance.drr.go.th/th/DRR the ref is indeed correct—it's listed as a paved road that runs 455 metres from Hwy 1184 to Ban Mae Ao School and first appeared in the reports for the 2014 fiscal year.

So the question is probably whether we'd want to base our tagging on the official classification for roads which are obviously not that important (this one is practically the school's driveway). As illustrated by Bernhard's examples, DRR roads have a tendency to vary in size and scale despite having the same type of ref numbers.

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#5 2018-05-08 08:01:02

stephankn
Moderator
Registered: 2010-05-04
Posts: 606

Re: Rural roads ref numbers

Hello Paul,

it is very strange. The road in question is not even near the school.
https://www.openstreetmap.org/way/535043410

What is missing on OSM is (besides the school and another school building west of it) the tertiary way, about 500m long from Hwy 1184 to the school. A nicely paved road. But according to StreetView ref 6043.

I still have the impression that we have discovered a fault in the data here.

Maybe someone got confused by these two roads and it was never corrected?
I know that official data is sometimes also buggy. Happened here in Germany when official street name lists with house numbers had been compared to the reality.

In this specific case I downgraded the road as it very much looks like a faulty data-set.

In general I would follow the official classification. A classified road would then be at least a tertiary and condition of the road is tagged by surface and other tags. This is how it is largely used.

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#6 2018-05-08 17:02:14

Paul_012
Member
Registered: 2011-08-05
Posts: 210

Re: Rural roads ref numbers

Oh. I was looking at the wrong road. It indeed looks like an error. The pdf gives the beginning of the road as the 2.450-km point of Hwy 1184, so it should actually be Way 483135756, which is currently classified as a track in our data. That doesn't explain the mismatch either.

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