[ale] WAY [OT] but geeky - how do I calibrate GPS barometric altimeter

Jim Kinney jim.kinney at gmail.com
Mon Feb 25 23:06:31 EST 2013


Ha!  I got the fam 4 Motorola Droid Razor M phones. Other than the case
color they are all 4 identical. All 4 show the weather for the same
location (Tucker) and we are all in the kitchen and all 4 phones show a
different outside temp!

I think some apps need some tuning :-)

On Mon, Feb 25, 2013 at 8:07 PM, Ron Frazier (ALE) <
atllinuxenthinfo at techstarship.com> wrote:

> I don't think Cumming has an airport, but I'll keep it in mind.
>
> I took the GPS out with me to supper.  When I left, my house was at 1210
> feet above sea level.  By the time I got back, it had sunk (on the display)
> to 1170 feet.  In the last 20 minutes of me sitting here, it has raised
> back up to 1185 feet.
>
> So, I guess I cannot expect too much from the elevation function of this
> device.
>
> Sincerely,
>
> Ron
>
>
> Pete Hardie <pete.hardie at gmail.com> wrote:
>
> >Go down to the airport - it's a well-specified lat/lon and alt, and a
> >weather station.
> >
> >Pete Hardie
> >--------
> >Better Living Through Bitmaps
> >
> >
> >On Mon, Feb 25, 2013 at 5:53 PM, Ron Frazier (ALE) <
> >atllinuxenthinfo at techstarship.com> wrote:
> >
> >> Hi all,
> >>
> >> I just got my hands on a neat Garmin Etrex Vista H handheld GPS on
> >> clearance for hiking trails and such.  It has a barometric altimeter
> >that I
> >> wish to calibrate.  I have to either enter an accurate known
> >barometric
> >> pressure; or I have to enter an accurate known elevation.
> >>
> >> I've checked Weatherbug (for Cumming, GA), The Weather Channel, and
> >the
> >> Firefox ForecastFox plugin.
> >>
> >> The barometric pressure readings are: 29.85, 29.92, and 29.90.  As I
> >> understand it, these variations would be enough to create altimeter
> >reading
> >> differences of around 70 feet.
> >>
> >> I can't necessarily use my weather station as a good barometric
> >pressure
> >> gauge, since it depends on elevation.  (I usually calibrate that
> >instrument
> >> by putting in the barometric pressure from The Weather Channel.)
> >>
> >> I don't know the exact elevation of my house, nor the exact elevation
> >at
> >> the trail at the park.
> >>
> >> I can calibrate to GPS elevation, but that's not very accurate.
> >>
> >> Garmin says the altimeter is accurate to 10 feet if properly
> >calibrated.
> >>  Of course, it will change with the weather.
> >>
> >> So, how can I determine accurate barometric pressure for a location,
> >or
> >> accurate elevation, so I can calibrate this thing?  Is there a way to
> >get
> >> elevation from google maps, or something?
> >>
> >> Note, this is not critical, not life threatening if I don't find the
> >> answer, not even exceedingly important.  But, I just want to get the
> >most
> >> usage out of the device that I can.  And, you guys are a great source
> >of
> >> geeky information of all sorts.
> >>
> >> Any help, as always, is appreciated.
> >>
> >> Sincerely,
> >>
> >> Ron
> >>
> >>
> >> --
> >>
> >> (PS - If you email me and don't get a quick response, you might want
> >to
> >> call on the phone.  I get about 300 emails per day from alternate
> >energy
> >> mailing lists and such.  I don't always see new email messages very
> >> quickly.)
> >>
> >> Ron Frazier
> >> 770-205-9422 (O)   Leave a message.
> >> linuxdude AT techstarship.com
> >>
> >> ______________________________**_________________
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> >> Ale at ale.org
> >>
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> >>
> >
> >
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>
> --
>
> Sent from my Android Acer A500 tablet with bluetooth keyboard and K-9 Mail.
> Please excuse my potential brevity if I'm typing on the touch screen.
>
> (PS - If you email me and don't get a quick response, you might want to
> call on the phone.  I get about 300 emails per day from alternate energy
> mailing lists and such.  I don't always see new email messages very
> quickly.)
>
> Ron Frazier
> 770-205-9422 (O)   Leave a message.
> linuxdude AT techstarship.com
>
>
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>



-- 
-- 
James P. Kinney III
*
*Every time you stop a school, you will have to build a jail. What you gain
at one end you lose at the other. It's like feeding a dog on his own tail.
It won't fatten the dog.
- Speech 11/23/1900 Mark Twain
*
http://electjimkinney.org
http://heretothereideas.blogspot.com/
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