----- Original Message -----
On Thu, May 26, 2011 at 12:26 PM, Benjamin Ducke
<benjamin.ducke@oxfordarch.co.uk> wrote:
>> Hm-hm. Citing from the website:
>> "The problem is that the ratio of change due to air to curvature is
>> not 1:7 (0.13), as the standard refraction coefficient suggests. It
>> is 0.325.
>
> As far as I can tell, this is a mis-understanding. The value "0.325"
> applies to radio waves. Visible light is very close to 1:7.What if I am interested in radio waves, not visible light, e.g. for
antenna relay positions? IMHO, that refraction coefficient should not
be hard-coded.
Agreed. It's a settable value in r.ecurv.comp and should also be one
in all GRASS modules that have refraction compensation.
Ben
>
> I realize the whole discourse is somewhat "clouded". But I don't
> have access to most of the relevant literature for the time
> being, nor do I have the necessary scientific backgroundMe neither. But any correction should take into account that the
observer is not necessarily a human without optical equipment
(telescope etc), but can also be some technical device, e.g. a sender
or receiver of whatever signals.my .2c
Markus M
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