Height Above Sea Level

[2sp_]

Following on from a random thought I had earlier today...

When we talk about landmarks being so many feet about sea level, where is that base level taken?

Is it high tide or low tide?

Can someone please explain in small words?

[2sp_]

*above sea level*

duh!

[jackthehat]

http://en.wikipedia.org/wiki/Ordnance_Datum

There ya go..... :o)

[paddywak]

Read this
https://www.google.co.uk/#bav=on.2,or.r_qf.&fp=d4115cfd9f96ecc5&q=sea+level

[2sp_]

Thank you JTH!

I've no idea why I was thinking about it today, but now I know!

[sigma]

What happens to the measurements if sea levels rise. Does that mean that the height of mountains, hills etc will be reduced.

[ToraToraTora]

it matters not what the sea level actually is, the ordnance datum is set, all levels are taken from that.