[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [gpsd-users] Position accuracy of AIS data in gpsd json?
From: |
Gary E. Miller |
Subject: |
Re: [gpsd-users] Position accuracy of AIS data in gpsd json? |
Date: |
Thu, 9 Aug 2018 10:41:22 -0700 |
Yo Sven!
I'll admit to being unfamiliar with the AIS code, few use it.
On Thu, 9 Aug 2018 17:33:37 +0200
Sven Geggus <address@hidden> wrote:
> looking at the code, I see, that lat/lon positions are truncated
> after the fourth decimal place (%.4f) when running in scaled mode.
Where exactly are you looking? In the JSON, or in one of the
clients?
> Looking at the spec, the accuracy of the messages should be 0.0001’
> which would be 0.0000017°
Citation? Which spec? I'm guessing that would be 0.617 feet at the
equator. Only survey grade GPS and RTK GPS are that accurate.
> So whats the rationale behind this behaviour?
Someone probably coded it to the same accuracy as the AIS they had.
> Would'nt %.6f be a more correct joice?
That would exceed the accuracy of any AIS I ever heard of. Maybe
%.5f would be best.
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
address@hidden Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin
pgpqW6s5keOTs.pgp
Description: OpenPGP digital signature
- [gpsd-users] Position accuracy of AIS data in gpsd json?, Sven Geggus, 2018/08/09
- Re: [gpsd-users] Position accuracy of AIS data in gpsd json?,
Gary E. Miller <=
- Message not available
- Re: [gpsd-users] Position accuracy of AIS data in gpsd json?, Gary E. Miller, 2018/08/09
- Re: [gpsd-users] Position accuracy of AIS data in gpsd json?, Sven Geggus, 2018/08/10
- Re: [gpsd-users] Position accuracy of AIS data in gpsd json?, Gary E. Miller, 2018/08/10
- Re: [gpsd-users] Position accuracy of AIS data in gpsd json?, Sven Geggus, 2018/08/11
- Re: [gpsd-users] Position accuracy of AIS data in gpsd json?, Gary E. Miller, 2018/08/11
- Re: [gpsd-users] Position accuracy of AIS data in gpsd json?, Sven Geggus, 2018/08/11
- Re: [gpsd-users] Position accuracy of AIS data in gpsd json?, Gary E. Miller, 2018/08/11