| Author |
Message |
Christian Caron
Guest
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 Posted:
Thu Dec 09, 2004 12:30 am Post subject:
calibrating altitude in GPSMAP 76S |
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Hi,
there is not much said about the calibration of altitude (barometer) in the
manual... Should it be calibrated? Does it calibrate itself? What's the best
way to calibrate (by entering a "real" elevation or a "real" pressure)?
Thanks!
Christian |
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Holger Issle
Guest
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| Posted:
Thu Dec 09, 2004 1:45 am Post subject:
Re: calibrating altitude in GPSMAP 76S |
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On Wed, 8 Dec 2004 14:30:40 -0500, "Christian Caron" wrote:
| Quote: | there is not much said about the calibration of altitude (barometer) in the
manual... Should it be calibrated? Does it calibrate itself? What's the best
way to calibrate (by entering a "real" elevation or a "real" pressure)?
|
Normally I have mine on automatic (meaning it takes averaged GPS
readings to calibrate the baro). In some cases this is not useful,
e.g. when you want to observe weather at sea level or climbing rocks
(bad reception) it might be useful to switch it off.
--
Ciao,
Holger (GUS-KOTAL, GUS#1100)
90-92 Honda CB400 10 Mm | 93-95 Yamaha TDM 850 26 Mm
95-97 KTM 620 LC4 13 Mm | seit 97 BMW R1100GS 50 Mm (Die Renndrecksau!)
cu @ http://www.issle.de |
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Roy
Guest
|
| Posted:
Thu Dec 09, 2004 9:31 am Post subject:
Re: calibrating altitude in GPSMAP 76S |
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"Christian Caron" <nospam@nospam.org> wrote in message
news:41b75660$1@webster...
| Quote: | Hi,
there is not much said about the calibration of altitude (barometer) in
the
manual... Should it be calibrated?
|
If you want the elevations to be as close as possible to what you see on
signs or maps: yes.
| Quote: | Does it calibrate itself?
|
Only if you tell it to. Menu Menu Setup Altimeter Autocalibrate On. Even
with Autocalibration turned on, you'll get the best results if you calibrate
the unit initially to a known elevation or pressure.
| Quote: | What's the best
way to calibrate (by entering a "real" elevation or a "real" pressure)?
|
In practice, probably whichever one you know more accurately. If you know
both the elevation and the pressure, use the elevation. The smallest
increment of pressure you can use is 0.01". If I change the calibration by
0.01", the elevation reading on the unit changes by about 8 feet. So if you
know the elevation to the nearest foot and use that to calibrate the unit,
you are calibrating with a value that has about 8 times more resolution, so
you can get closer to the "real" value. But really, in real use it will
hardly matter.
I often just calibrate to the current GPS altitude and let autocalibrate
fine tune it from there. It may be off by quite a bit initially, but it
gets the unit in the general ballpark and autocalibrate will get it closer.
Comparing my elevation readings to elevations of mountain lakes published on
maps, my results using this method have been surprisingly good, even when I
have left the unit off most of the time and only turned it on for a few
minutes every half-hour or so to locate myself on a map. I should say that
I've only been able to make that comparison a couple of times, so it could
just be that I was lucky.
--
Regards,
Roy |
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Brian Ludwig
Guest
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| Posted:
Mon Dec 13, 2004 12:27 am Post subject:
Re: calibrating altitude in GPSMAP 76S |
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"Holger Issle" <Holger@issle.de> wrote in message
news:jsper0lv5268vv24oen7dgokvbpjet3lr2@4ax.com...
| Quote: | On Wed, 8 Dec 2004 14:30:40 -0500, "Christian Caron" wrote:
there is not much said about the calibration of altitude (barometer) in
the
manual... Should it be calibrated? Does it calibrate itself? What's the
best
way to calibrate (by entering a "real" elevation or a "real" pressure)?
Normally I have mine on automatic (meaning it takes averaged GPS
readings to calibrate the baro). In some cases this is not useful,
e.g. when you want to observe weather at sea level or climbing rocks
(bad reception) it might be useful to switch it off.
--
Ciao,
Holger (GUS-KOTAL, GUS#1100)
90-92 Honda CB400 10 Mm | 93-95 Yamaha TDM 850 26 Mm
95-97 KTM 620 LC4 13 Mm | seit 97 BMW R1100GS 50 Mm (Die Renndrecksau!)
cu @ http://www.issle.de
|
Hi Ciao
Can you give me some idea of how you manully set your altitude. I ma
especially interested in using it to determine weather patterns by watching
the barometer over time.
Can you help please /
Regards
Brian (Edinburgh - Scotland) |
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