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Re: [gpsd-dev] ✘CEP(50) 0.285 metersMime-Version: 1.0

From: Hal Murray
Subject: Re: [gpsd-dev] ✘CEP(50) 0.285 metersMime-Version: 1.0
Date: Fri, 22 Jul 2016 17:45:03 -0700

address@hidden said:
> Spherical distances are tricky, and ISTR that GPSD switched distance
> algorithms at one point.  You almost certainly don't want the simple
> spherical law-of-cosines formula, since that has awful numerical
> sensitivities for short distances. 

I'd expect distances for nearby points would be simple.

I'm assuming you start with LAT/LON.  Subtract LAT and LON.  LAT converts to 
feet/meters by diameter of the Earth.  LON is similar but gets scaled by cos 
of LAT.

These are my opinions.  I hate spam.

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