Barometric altimeter on 'future' Freerunner ?
Al Johnson
openmoko at mazikeen.demon.co.uk
Sun May 18 12:58:06 CEST 2008
On Sunday 18 May 2008, adam at laurasteele.net wrote:
> GPS does give relatively accurate altitude/speed but it does have
> error and is nowhere near as accurate as a calibrate barometer (since
> an aircraft altimeter is just a barometer with a different face).
>
> Assuming someone has a data plan you can get the barometric pressure
> from a nearby airport (most have a weather station, all data is pooled
> by the FAA online**). Wouldn't be sure about other countries but I bet
> France/most sizable would have something similar. That or you could
> assume the "standard" 29.92 in/Hg and 1000ft per 1 in/Hg.
>
> An even more desperate thing you could do is call 1800-WX-BRIEF and
> ask what the baro is at a local airport.
>
> **They also maintain a very detailed list of all airports available as
> an XLS file.
The airport information is available globally, and used by the kweather panel
applet. It looks like policy may vary by country for the size of airport to
be listed, but generally speaking it'll be listed if it handles international
flights.
kweather lists temperature, air pressure, wind speed and direction, sunrise
and sunset, dewp oint and relative humidity. I haven't looked to see if
anything else is published, or what the update interval is.
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