#1584 closed defect (fixed)
error in r.walk help page
Reported by: | hamish | Owned by: | |
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Priority: | major | Milestone: | 7.2.0 |
Component: | Docs | Version: | svn-releasebranch64 |
Keywords: | r.walk | Cc: | Agustin.Lobo@… |
CPU: | All | Platform: | All |
Description
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.
Change History (7)
follow-up: 2 comment:1 by , 12 years ago
comment:2 by , 12 years ago
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.
comment:3 by , 12 years ago
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.
comment:4 by , 12 years ago
Version: | unspecified → svn-releasebranch64 |
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follow-up: 6 comment:5 by , 9 years ago
Milestone: | 6.4.3 → 7.1.0 |
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Bumped for check to 7.1. In case backports down to G6.4 are needed.
comment:6 by , 9 years ago
Resolution: | → fixed |
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Status: | new → closed |
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: