On Mon, 17 Dec 2012 21:37:34 -0500, Spehro Pefhany
wrote:

On Mon, 17 Dec 2012 20:04:25 -0600, the renowned Richard
wrote:

On 12/17/2012 6:04 PM, Spehro Pefhany wrote:
oblate spheroid

You are kidding, right?

Mean radius 6,371.0 km[6]

Equatorial radius 6,378.1 km[7][8]
Polar radius 6,356.8 km[9]

I'm seeing that as 22 km of "oblative flattening".

You'd have to mike it to tell the difference.

(BIG micrometer)

http://en.wikipedia.org/wiki/World_Geodetic_System

WGS84 is used by GPS, GLONASS,

http://koti.mbnet.fi/jukaukor/greatc...ellipsoid.html

This will get you down to the millimeter level, not micrometer. ;-)

For example, from Toronto to Chicago is 702.9810543723332 km elliptic,
but the spherical solution gives only 700.9181433797103 km. That's an
error of more than 2,000 meters.. that could put you on the wrong
runway or something.

http://www.wtsp.com/news/article/264...rport-in-Tampa



What altitude are you flying at??? Makes a SMALL difference too.


Best regards,
Spehro Pefhany