error in r.walk help page

[hamish]

one from Agustin:

the documentation in r.walk is wrong. It says:
"The default values for a, b, c, d are those proposed by Langmuir
(0.72, 6.0, 1.9998, -1.9998)"
and it should say:
"The default values for a, b, c, d are those proposed by Langmuir
(0.72, 6.0, -1.9998, 1.9998)"

because the point is that you go faster on gentle slopes and more
slowly on steeper slopes and those values are in m/s
The worrying question is whether these values are also wrong in the
default values of r.walk.

[dkavanagh]

There is also a mistake in the Standard Directions figure in the Movement Direction section. 90 should be immediately below x and the zero should be removed.

Replying to hamish:

one from Agustin:

the documentation in r.walk is wrong. It says:
"The default values for a, b, c, d are those proposed by Langmuir
(0.72, 6.0, 1.9998, -1.9998)"
and it should say:
"The default values for a, b, c, d are those proposed by Langmuir
(0.72, 6.0, -1.9998, 1.9998)"

because the point is that you go faster on gentle slopes and more
slowly on steeper slopes and those values are in m/s
The worrying question is whether these values are also wrong in the
default values of r.walk.

[dkavanagh]

My note applies to 6.5 and 7.0. The Langmuir correction applies to all versions.

Replying to dkavanagh:

There is also a mistake in the Standard Directions figure in the Movement Direction section. 90 should be immediately below x and the zero should be removed.

Replying to hamish:

one from Agustin:

the documentation in r.walk is wrong. It says:
"The default values for a, b, c, d are those proposed by Langmuir
(0.72, 6.0, 1.9998, -1.9998)"
and it should say:
"The default values for a, b, c, d are those proposed by Langmuir
(0.72, 6.0, -1.9998, 1.9998)"

because the point is that you go faster on gentle slopes and more
slowly on steeper slopes and those values are in m/s
The worrying question is whether these values are also wrong in the
default values of r.walk.

[dkavanagh]

Hamish - I believe the help is correct. c and d are multiplied by the delta, which in a downward slope will be negative. Here is an example from the code - fcost_dtm = (double)((double)(W_dtm - my_dtm) * c);

Replying to hamish:

one from Agustin:

the documentation in r.walk is wrong. It says:
"The default values for a, b, c, d are those proposed by Langmuir
(0.72, 6.0, 1.9998, -1.9998)"
and it should say:
"The default values for a, b, c, d are those proposed by Langmuir
(0.72, 6.0, -1.9998, 1.9998)"

because the point is that you go faster on gentle slopes and more
slowly on steeper slopes and those values are in m/s
The worrying question is whether these values are also wrong in the
default values of r.walk.

[neteler]

Bumped for check to 7.1. In case backports down to G6.4 are needed.

[annakrat]

Replying to neteler:

Bumped for check to 7.1. In case backports down to G6.4 are needed.

I was looking into that recently in 7 and I think it's fine. I backported some of the documentation in r65411.

[neteler]

Milestone renamed