Altimeter
Submitted: Sunday, Oct 20, 2019 at 09:44
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Member - John L43
Hi everyone. I have a Galaxy Tab 8 where I have the Explore Oz app. I like it alot, but the altimeter put me below sea level when I get near the coast, and is about 15 meters out everywhere else. Has anyone found this on theirs and is it EO or the tab 8 fault? Is there a fix for it as I really dont like being 6' under, so to speak.
Reply By: Member - Boobook - Sunday, Oct 20, 2019 at 12:25
Sunday, Oct 20, 2019 at 12:25
John, apart from being the least accurate of the measurements, height, or Z is the least understood parameter.
A raw GPS reading does not show height above sea level, it can't because the GPS system has no idea what sea level is. If you are using WGS 84, it will give you height above that model of the earth and sea level which on average across the whole world is the same as sea level. But in reality, can be a few meters or more different because the model earth shape is not the same as the real world's shape.
So, like your experience, the GPS can show that you are several m below WGS84 sea level, but still above the real sea level.
I am not sure how EO handles this, but in Memory Map, you can download the actual date for height above sea level across the world. You can either display that, or GPS height or both. They are rarely the same thing. The height above sea level is downloaded from satellite Dopler height data from NASA. I think Oziexplorer can do the same. It took me ages to figure out why Memory map showed both and they were different values.
If EO can display height above sea level you should use that, otherwise, accept that your displayed GPS height can be different to your height above sea level depending on where you are.
When you are away from the sea, you rarely notice this, unless you are a
sign showing altitude above sea level, but if it says 1355m and your GPS shows 1345m you tend to dismiss the difference.
Ausgoid 09 goes some way to address this if it is supported.
Then, of course, there is the actual tide which could be higher or lower than the average.
AnswerID:
628229
Reply By: Member - John L43 - Monday, Oct 21, 2019 at 22:17
Monday, Oct 21, 2019 at 22:17
Thanks to everyone who made comments. Seems I cant do much about the altitude in this unit, and it really doesnt matter that much anyway. Just as
well I can breathe under the sand at
the beach!!!!!.
I also use my iphone8 with motion X GPS, when I am out and about, which has other benefits over ExploreOz.
Anyway, all is
well and I am grounded.
AnswerID:
628255