Arthur Carlson wrote:
> Fernando Cabral <[EMAIL PROTECTED]> writes:
> > I do think this method is easier and more precise than the compass and
> > the GPS (at least in "normal" usage).
>
> I agree that a shadow method is likely to be easier and more precise
> than using either a compass or GPS, but I have some comments on your
> exposition. First, the clock time of the readings is not
> important. In the afternoon, you want the locations where the shadow
> of the nodus crosses each circle, regardless of what your watch says
> the time is.
You are absolutely RIGHT. My idea was not to suggest that the time
was important. It is not, as you correctly say. The idea -- which I did not
express correctly -- was that if you know that you made the first mark
at 11 am, than the second one will be around 1 pm. So you can go
for lunch and come back (say) 15 to 1 and wait until the shadow meets
the circle. If you mark at 9 am then you should be back at 3 pm, so
on and so forth.
The only function of reading the watch is spare your time.
So, thank you for clarifying this important point.
> Second, the accuracy of the result can be compromised if
> the ground is not level from East to West. For high precision, you
> will first need to prepare a level surface for the shadows to fall on.
Right again.
- fernando
>
>
> Regards,
>
> Art Carlson
--
Fernando Cabral Padrao iX Sistemas Abertos
mailto:[EMAIL PROTECTED] http://www.pix.com.br
Fone Direto: +55 61 329-0206 mailto:[EMAIL PROTECTED]
PABX: +55 61 329-0202 Fax: +55 61 326-3082
15º 45' 04.9" S 47º 49' 58.6" W
19º 37' 57.0" S 45º 17' 13.6" W
