ศาลาชุมนุม

[Phaethon]

There is a pillar situated outside the National Museum which, according to my reading of the title, shows the high water marks for various floods in the past:
http://tyfon.info/TV/PA266050c.JPG
http://tyfon.info/TV/PA266051b.JPG

The title reads:

ระดับน้ำทำมสูงสุด which I decoded as "Highest Water Levels"

The marked character confused me. I thought it might be ม to represent 'metre', making it "Highest Water Levels in m." but the levels recorded are:

พ.ศ. 2485 (BE 2485 > CE 1942) 37 . 500
พ.ศ.2521 (BE 2521 > CE 1978) 37 . 130
พ.ศ.2526 (BE 2526 > CE 1983) 37 . 000

Surely Bangkok isn't/wasn't 37m above sea-level where/when this was placed, so what measurement system/baseline is in use here and what is the stray ม? Is it even a ม ?

Cheers,

[David and Bui]

น้ำท่วม "highest flood level"

[Phaethon]

Ah, thanks David, I should have recognised 'thuaam' but what I now see is a ว looks identical to the preceeding า of ำ - very slightly more curved at the bottom

But still I don't get the 37.000 baseline, I didn't get a tape measure out but the markings look about right for metric (whole thing is almost 2m high), but 37?

[David and Bui]

Could we see that portion of the sign which shows the heights?

Perhaps the measure is http://www.thai-language.com/id/25339 (definition 2) or http://www.thai-language.com/id/147613 .

[Phaethon]

Could we see that portion of the sign which shows the heights?

The figures are on the front seen in the first link. There is a scale on the left side visible in the second picture.

[David and Bui]

My Thai engineer friend thought that the markings were in Centimeters.

[Phaethon]

A couple of weeks ago I came across a GPS reference marker in Suan Rommaninat, not far from Sanam Luang. The marker gives the elevation for that point in Bangkok according to the reference sphere defined by the WGS84 system of -0.0382m. Updated versions of WSG84 is the system used for the world GPS system. However, the marker also gives the measurements according to the earlier Indian1975 system whose reference sphere gives Bangkok reference point (on a pillar about half a metre high) an elevation of 37.5729m.

So, it seems the measurements of the flood levels on the flood pillar are based on the Indian1975 system and not any sea-level based system.

Details and pictures of the pillar and the reference point at:
http://phaethon.net/photobkk/index.php/ ... od-pillar/