"Jukka K. Korpela" wrote in message
. ..

In practice, using hPa means being just _nominally_ metric, i.e. using
actually millibars but under a different name. The odd thing is that
the correct kPa would be more practical.

How can you possibly suggest that it would be more "practical" to use kPa?
There is an installed base of tens of thousands of altimeters in aircraft
out there that are calibrated in mbar. Describing them as hPa makes it
clear what the unit is for someone familiar with the SI, without risking
accidents through unit confusion.

The preference to use powers of 1000 is just a preference because
practicality and pragmatism is sometimes more important than an arbitrary
recommendation. This is a perfect example of where pragmatism should (and
does) win.

Julian Scarfe