[meteorite-list] re: I'm getting confused by the MB coordinates

From: Walter L. Newton <newtonw2_at_meteoritecentral.com>
Date: Sat Aug 26 09:08:47 2006
Message-ID: <001b01c6c910$76afcbd0$ed760818_at_walter>

Back again

Ok... I did a little self searching on this topic of map datum used for lat.
and long. on MB entries.

There are different sets of map datum that have been use (and some still
being used) to locate the "zero point" on a map (or the whole planet), from
which the measurements are made from.

Google Earth places item on it's maps using WGS-84 (World Geodetic System
1984) datum.

All older US government topological maps used NAD27 (North American Datum
1927) based on a zero point at Meades Ranch in Kansas. Use of this datum is
being replaced by NAD83 datum.

I found a online map datum converter calculator at...

http://jeeep.com/details/coord/

... and used it to convert the MB coordinates for the Russell Gulch Colorado
1863 find and the Apex Colorado 1938 find, to see if the MB coordinates from
that time were using the NAD27 datum point.

Well, that only placed the find spots 200 meters closer (south) to the
actual find spots.

So, that's not my answer. The answer is the MB coordinates may not reflect
the actual find spot in all cases.

Now, I understand that the MB folks are busy and cannot personally go out
and check every find spot in their database. And the information given to
them is sometimes over a 100 years old (as in the case of Russell Gulch
1863).

But some of us meteorite collectors can. In the case of the Apex Colorado
find, I don't even have to go anywhere (even though the real find spot is
only 4 miles from me). All I had to do was read the narrative that came with
the MB listing, realize that the narrative names verifiable places as the
find spot, and in my case, verify the information by talking to Jack Murphy,
ex-curator of the Denver Museum of Natural History (now known as Denver
Museum of Nature and Science).

And in the case of the Russell Gulch find, as I mentioned in my last post,
my girlfriend, who lives in Russel Gulch, is going to put me in contact with
a "old timer" who has information on the actual find spot. So I may be able
to place this meteorite closer to the actual find spot.

This may sound like a trivial pursuit (that would make a good name for a
game), but I know if I wanted to hunt a old find spot for possible new
finds, I would like to be a bit closer than 4 miles from the find.

I don't know if the MB folks would want to start dealing with changes like
this, but I think it's something to consider.

This is a science, and I would think that we would want our data to be as
accurate as possible.

Walter L. Newton
Golden, Co

P.S: Russell Gulch should be spelt with ONE "L." It seems somewhere in time
the double "L" spelling became the norm, but I guess spelling is not a
science.
Received on Sat 26 Aug 2006 09:06:36 AM PDT