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#1 2021-02-22 11:51:10

AlaskaDave
Member
From: Homer, Alaska ; Chiang Mai
Registered: 2013-09-21
Posts: 424
Website

Thailand-Myanmar boundary

Hi all,

Since taking up bird photography I've been spending a lot of time in the Doi Pha Hom Pok National Park in northern Thailand. There is a road there that is used by birders to access the high ridges that separate the two countries. Looking at the OSM map one might assume that this road, the Doi Lang-Doi San Ju Road, crosses back and forth between the two countries many times. IMO, such a situation is highly unlikely considering the mutual dislike and mistrust of both governments. My guess is that the boundary is either wildly misplaced or so imprecise as to be almost useless.

Conversations with locals suggest that the Doi Lang-Doi San Ju Road (OSM Way: 139216140 in the area of interest), may be the actual boundary between the countries. The boundary has OSM id:140845202. My thought was to place the boundary and the road in a boundary relation to consolidate them. It's not a critical issue but I feel it's worthy of some thought and perhaps some more research.

Does anybody have information or opinions to share?

Cheers,

Dave

Last edited by AlaskaDave (2021-02-22 13:05:22)

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#2 2021-02-22 13:25:53

Tom Layo
Member
Registered: 2011-01-30
Posts: 72

Re: Thailand-Myanmar boundary

I've done this many times because there just isn't anything else you can do. Once I determine that a village is in a chenwat on the wrong side of a boarder, I move the boarder. I'm virtuallly certain it's the right thing to do. Same with moving boarders to coinside with rivers.

As Jimmy Wales said about Wikipedia editing, "Be bold".

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#3 2021-02-22 13:28:52

Tom Layo
Member
Registered: 2011-01-30
Posts: 72

Re: Thailand-Myanmar boundary

Where is the spell checker? Border. Doh!

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#4 2021-02-22 19:27:47

Bernhard Hiller
Member
Registered: 2011-05-10
Posts: 1,023

Re: Thailand-Myanmar boundary

The borders were originally some imports from a CIA database or something like that, without high precision.
With better imagery available, sometimes "border structures" can be seen. I updated then some parts of the Thai-Malaysian border.
By the way, the border roads there are not directly on the border, but a few meters away, e.g.
https://www.openstreetmap.org/way/24471 … 7/100.2904
South-east from Padang Besar, border roads are on both sides.
Hence I would not use the road in the border relation.

Last edited by Bernhard Hiller (2021-02-22 19:29:00)

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#5 2021-02-22 22:05:39

stephankn
Moderator
Registered: 2010-05-04
Posts: 581

Re: Thailand-Myanmar boundary

There should be government official documents available describing the border. Probably in textual for like "in the middle of the river xxx" or similar.
Getting such non-physical boundaries right is extremely tricky. If it is reasonable to assume a border follows a river, then updating it is probably better than the old import from the old days where landsat was the typical imagery.

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#6 2021-02-23 05:27:43

AlaskaDave
Member
From: Homer, Alaska ; Chiang Mai
Registered: 2013-09-21
Posts: 424
Website

Re: Thailand-Myanmar boundary

stephankn wrote:

There should be government official documents available describing the border. Probably in textual for like "in the middle of the river xxx" or similar.
Getting such non-physical boundaries right is extremely tricky. If it is reasonable to assume a border follows a river, then updating it is probably better than the old import from the old days where landsat was the typical imagery.

But where can we get such documents?

Thanks all for the responses.

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#7 2021-02-23 10:44:15

stephankn
Moderator
Registered: 2010-05-04
Posts: 581

Re: Thailand-Myanmar boundary

I assume that in Thailand or Myanmar, bilateral state treaties are made public in some form.
Not certain whether they are available online.
You should be able to look them up in some government agency and probably also be able to make copies (potentially for a small fee).

This is currently out of scope for my language level of Thai. Others might be able to come up with documents. Maybe Mishari knows where to search, as he worked with some of the open-data before.

Here you can read up how other countries deal with border definitions, for example the longest land border:

https://en.wikipedia.org/wiki/Canada%E2 … tes_border

As you can see, even they have disputed areas, which is then another obstacle you might face. There is a specific tagging on how to mark disputed borders.

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#8 2021-02-23 11:31:44

AlaskaDave
Member
From: Homer, Alaska ; Chiang Mai
Registered: 2013-09-21
Posts: 424
Website

Re: Thailand-Myanmar boundary

I turned up a good source of Thailand shapefiles for all administrative levels just now. It is located here:
http://thaigis.net/thailand-gis-resources/. From that page I jumped to the first link which took me to the UN-OCHA Humanitarian Data Exchange Project main page

On that page, I downloaded this ZIP file (https://data.humdata.org/dataset/thaila … boundaries) which contains administrative level 0 (country), 1 (province), and 2 (district) boundaries, unzipped it and loaded the Admin level 0 SHP into JOSM. As I suspected, the boundary OSM has in the area of interest is poorly positioned in many places. In other places, it's fairly accurate. Interestingly, the boundary runs right through the center of some of the Thai Army camps that guard the border. I did not see any instance of the boundary crossing the Doi Lang-Doi San Ju Road.

Unfortunately, the data is not without usage limitations. It is administered by the UN-OCHA Humanitarian Data Exchange Project, whatever that is. It is quite possible that we could get permission to use their data but I did not take that step.

The name UN-OCHA Humanitarian Data Exchange Project sounds as though exchanging data with them (they use OSM on the website) should be easy. But, maybe not. If I decide to spend some time researching this, I'll let you know.

This would be a wonderful resource for Thailand OSM mappers. Shapefiles are available for landcover, parks and other man_made features. It's a virtual treasure chest!

Cheers,

Dave

Edit: I might have been too enthusiastic about that website. I returned to it and couldn't find parks or landcover on it. I must've seen those elsewhere. Still, accurate admin boundaries would be nice to have.

Last edited by AlaskaDave (2021-02-24 01:27:56)

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#9 2021-02-26 04:36:12

Paul_012
Member
Registered: 2011-08-05
Posts: 208

Re: Thailand-Myanmar boundary

There's a series of US Department of State documents from the 1960s called the International Boundary Studies. Most can be found on the web with a Google search, if one knows the keywords. A copy of the one describing the Thailand-Myanmar border can be found at https://fall.fsulawrc.com/collection/Li … IBS063.pdf . Mostly, the border will follow rivers or mountain ridges, so if the terrain is clearly visible enough in the imagery one can draw a reasonably accurate representation by following the zigzagging spines of the mountains. The level of detail, though, probably isn't going to be much better than that of the LSIB data (the source of the latest import). We're talking inaccuracies of mostly less than 100 m; this will require visible detailed features such as fences (as with the Malaysian border mentioned by Bernhard Hiller) or, as AlaskaDave noted in the OP, roads. (I wouldn't actually expect to find entire villages on the wrong side with this data source, though.)

Personally, I've only manually adjusted borders where the visible features are very obvious, e.g. there's a fence, or a pair of roads that clearly belong on different sides. A single road seems rather difficult to gauge—does it run exactly alongside the border, or how far away is it (or even whose side does it belong to)? In this case, the on-the-ground information would indicate that this road should be on the Thai side, so I guess it should be safe to adjust accordingly.

PS If anyone feels like it they could try checking the LSIB (Large Scale International Boundaries) to see if the latest version is more updated/accurate in the relevant areas (though I don't think it's likely).

Edit: Oh, just re-read the OP and saw that the suggestion was that the road exactly corresponds to the boundary. I'm not so sure about this; seems like a rather strange arrangement.

Last edited by Paul_012 (2021-02-26 05:07:54)

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#10 2021-02-26 08:52:57

stephankn
Moderator
Registered: 2010-05-04
Posts: 581

Re: Thailand-Myanmar boundary

Getting the state border right is a sensitive topic.

Using some US source to define the border of a different foreign state doesn't sound right.

The initial import into OSM only had very approximate borders. Most involved had been aware.

If updating them now, we should use a better source.

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#11 2021-02-26 10:00:52

AlaskaDave
Member
From: Homer, Alaska ; Chiang Mai
Registered: 2013-09-21
Posts: 424
Website

Re: Thailand-Myanmar boundary

Edit: Oh, just re-read the OP and saw that the suggestion was that the road exactly corresponds to the boundary. I'm not so sure about this; seems like a rather strange arrangement.

Quite right, Paul. It was only a starting place for my investigation. I thought it very unlikely that the boundary crisscrossed the Doi Lang-Doi San Ju Road and that started me looking for an explanation or some other way to verify my suspicion.

Subsequently, I added a comment that talks about the accuracy of the updated boundary I found online and indeed, the boundary lies directly alongside the Doi Lang-Doi San Ju Road in several places but it's always on the Myanmar side, and it never crosses that road. The people that suggested the boundary follows the road were only approximately right.

I did a little more probing of the HDX site I found and it contains the following statement:

"Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution 4.0 International license."

What does this mean?

Last edited by AlaskaDave (2021-02-26 10:05:17)

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