Well, MapSource is wrong - depending on how accurate we would like to
be.
The foot of my driveway is:
N34 07 43.8
W84 32 40.0
The coordinates MapSource give are the center of the street - 2 houses
up the block. This is where Google Earth thinks I live as well - both
are incorrect.
I've done extensive boating on Alatoona - the GPS maps for Alatoona have
inaccurate GPS coordinates as well - and they are all off about the same
- typically you are 300-400 feet North and about 50 feet West of where
the databases say you are. The coordinate databases for this part of GA
can only be counted on to around 600 foot accuracy in my experience,
although in a few cases they appear to be dead on.
For accuracy discussions it would be nice if we could use the
engineering standard - 10 times better than the last digit given. If
MapSource gives coordinates to a tenth of a second, they should be
accurate to 1/100th of a second. They are not even close, of course.
Worst case, MapSource needs to give its last digit plus or minus some
small error band - it does not meet that either.
For the SECC circle, MapSource may be good enough, except for those
cases where the station is not at the same property as the license, but
MapSource will never get you to my house - it will take you next door to
my next door neighbor's house. Tony Soprano lives there.
GG
---Original Message-----
From: Chaz Cone [mailto:chaz at chazcone.com]
Sent: Thursday, June 07, 2007 10:58 AM
To: Hal Kennedy
Subject: Re: [SECC] Location - N4GG
According to MapSource (per Garmin) your QTH is at:
N34 07 42.6 W84 32 41.2
Which should be the foot of your driveway.
C
At 06:06 AM 6/7/2007, you wrote:
The N4GG QTH is at:
34 deg, 07',44.4" North
84 deg, 32", 39.9" West
Its interesting to me to see that Google Earth has my address vs. true
position off by about 300 feet, and Buckmaster is off by 13 seconds in
lat and 9 seconds in long (not too bad).
Neil, K4EA, and Don, W4OC, we need your true locations...
Hal
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