On Wed, 1 Jun 2016 14:06:00 +0100, bert wrote:

I don't think that is correct
The 1 in 4 notation measure the sine of the angle not the tangent.
It's a rise of 1 foot for each 4 feet you travel up the gradient.

um, now not sure. If the gradient is 1:1 (100%) at 45 deg., that suggests
tan. The diagram showed, IIRC, Opp/Adj which I think is Tan.

yes . I always thought it referred to distance along teh map and height
above sea level, which is tan.

Then at some point someone else assured me it was sine, and now we are
back to tan.

The page linked to seems pretty definite that its tan so I'll go with
that for now


I always thought that the 1in 4 style notation was in fact sine, i.e.
opposite over hypotenuse

That would be more useful in the real world, as hypotenuse is measurable on
the road and opposite can be taken from a map. Both of these are needed to
get the adjacent, as that would be difficult to measure without a tunnel.
--
Peter.
The gods will stay away
whilst religions hold sway

On 01/06/16 16:14, PeterC wrote:
On Wed, 1 Jun 2016 14:06:00 +0100, bert wrote:

I don't think that is correct
The 1 in 4 notation measure the sine of the angle not the tangent.
It's a rise of 1 foot for each 4 feet you travel up the gradient.

um, now not sure. If the gradient is 1:1 (100%) at 45 deg., that suggests
tan. The diagram showed, IIRC, Opp/Adj which I think is Tan.

yes . I always thought it referred to distance along teh map and height
above sea level, which is tan.

Then at some point someone else assured me it was sine, and now we are
back to tan.

The page linked to seems pretty definite that its tan so I'll go with
that for now


I always thought that the 1in 4 style notation was in fact sine, i.e.
opposite over hypotenuse

That would be more useful in the real world, as hypotenuse is measurable on
the road and opposite can be taken from a map. Both of these are needed to
get the adjacent, as that would be difficult to measure without a tunnel.

If you can take opposite from the map why not adjacent?



--
djc

(–€Ì¿Ä¹Ì¯–€Ì¿ Ì¿)
No low-hanging fruit, just a lot of small berries up a tall tree.

On 01/06/16 20:51, DJC wrote:
On 01/06/16 16:14, PeterC wrote:
On Wed, 1 Jun 2016 14:06:00 +0100, bert wrote:

I don't think that is correct
The 1 in 4 notation measure the sine of the angle not the tangent.
It's a rise of 1 foot for each 4 feet you travel up the gradient.

um, now not sure. If the gradient is 1:1 (100%) at 45 deg., that
suggests
tan. The diagram showed, IIRC, Opp/Adj which I think is Tan.

yes . I always thought it referred to distance along teh map and height
above sea level, which is tan.

Then at some point someone else assured me it was sine, and now we are
back to tan.

The page linked to seems pretty definite that its tan so I'll go with
that for now


I always thought that the 1in 4 style notation was in fact sine, i.e.
opposite over hypotenuse

That would be more useful in the real world, as hypotenuse is
measurable on
the road and opposite can be taken from a map. Both of these are
needed to
get the adjacent, as that would be difficult to measure without a tunnel.

If you can take opposite from the map why not adjacent?
In reality a sextant or theodolite can do any of the above






--
€œit should be clear by now to everyone that activist environmentalism
(or environmental activism) is becoming a general ideology about humans,
about their freedom, about the relationship between the individual and
the state, and about the manipulation of people under the guise of a
'noble' idea. It is not an honest pursuit of 'sustainable development,'
a matter of elementary environmental protection, or a search for
rational mechanisms designed to achieve a healthy environment. Yet
things do occur that make you shake your head and remind yourself that
you live neither in Joseph Stalins Communist era, nor in the Orwellian
utopia of 1984.€�

Vaclav Klaus

On 01/06/2016 22:06, The Natural Philosopher wrote:
On 01/06/16 20:51, DJC wrote:
On 01/06/16 16:14, PeterC wrote:
On Wed, 1 Jun 2016 14:06:00 +0100, bert wrote:

I don't think that is correct
The 1 in 4 notation measure the sine of the angle not the tangent.
It's a rise of 1 foot for each 4 feet you travel up the gradient.

um, now not sure. If the gradient is 1:1 (100%) at 45 deg., that
suggests
tan. The diagram showed, IIRC, Opp/Adj which I think is Tan.

yes . I always thought it referred to distance along teh map and
height
above sea level, which is tan.

Then at some point someone else assured me it was sine, and now we are
back to tan.

The page linked to seems pretty definite that its tan so I'll go with
that for now


I always thought that the 1in 4 style notation was in fact sine, i.e.
opposite over hypotenuse

That would be more useful in the real world, as hypotenuse is
measurable on
the road and opposite can be taken from a map. Both of these are
needed to
get the adjacent, as that would be difficult to measure without a
tunnel.

If you can take opposite from the map why not adjacent?
In reality a sextant or theodolite can do any of the above


Indeed. And it might save a lot of angst if we specified gradients in
terms of angle with the horizontal - so my 15% slope would simply be 8.6
degrees - although at small angles like that, there's little difference
between sine and tangent.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Wed, 1 Jun 2016 20:51:22 +0100, DJC wrote:

On 01/06/16 16:14, PeterC wrote:
On Wed, 1 Jun 2016 14:06:00 +0100, bert wrote:

I don't think that is correct
The 1 in 4 notation measure the sine of the angle not the tangent.
It's a rise of 1 foot for each 4 feet you travel up the gradient.

um, now not sure. If the gradient is 1:1 (100%) at 45 deg., that suggests
tan. The diagram showed, IIRC, Opp/Adj which I think is Tan.

yes . I always thought it referred to distance along teh map and height
above sea level, which is tan.

Then at some point someone else assured me it was sine, and now we are
back to tan.

The page linked to seems pretty definite that its tan so I'll go with
that for now


I always thought that the 1in 4 style notation was in fact sine, i.e.
opposite over hypotenuse

That would be more useful in the real world, as hypotenuse is measurable on
the road and opposite can be taken from a map. Both of these are needed to
get the adjacent, as that would be difficult to measure without a tunnel.

If you can take opposite from the map why not adjacent?


Of course! Not thinking - too long in The Malt Shovel Tavern!
--
Peter.
The gods will stay away
whilst religions hold sway