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In a message dated 1/18/02 2:23:55 PM Eastern Standard Time,
jared.sherman@VERIZON.NET writes:


> Bill-
> NAD 83 --  30:16:28.82N, 97:44:25.19W --or-- 30d16m28.77992N,
> 97d44m25.10907s
> NAD-27 --  30:16:28.03N, 97:44:24.09W
> WGS-72 --  30:16:28.68N, 97:44:25.75W
>
> Interesting because using the USGS "Corpscon" conversion tool, I entered
> the NAD27 position and asked for the NAD83 position, which as you can see
> differs from the ones that the Texans found. Question being, did they read
> a map and measure from it? Or convert datums, using a formula different
> from the one the USPS supplied?
>

I do not know.  That star in Liberty's hand must be one of the most unique
benchmarks in the United States.  If you go to:

http://www.ngs.noaa.gov/cgi-bin/ds_mm.prl

and bracket the location one minute each way, it will give you a data sheet
with all the information that the NGS has on the control point including its
location on a couple of different datums (sp?).

Still, the star has different locations on different datums (sp?), but what
is its location with respect to (projected from the center of the earth onto)
a sphere located by a plane in the heavens formed by the earth's equator and
a similar perpendicular plane passing through both the center of the earth
and a certain telescope mount in Greenwich England ?  And, what is the
largest difference exists between that celestial coordinate system and a
modern chart datum.

Does your conversion program make that conversion ?

Bill Murdoch

   

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