[Gvsig_english] Cost Analysis with SEXTANTE

[Da Kn]

sorry, sent it too early (damn hotkeys)

 Dear List,
>
> SEXTANTE offers a lot of different methods for cost-analysis issues. I'm
> especially interested in anisotropic analysis and there are 2 methods for
> it: A and B. B lets you enter some values for difference and factor into a
> table. What does this exactly mean? If I want to create cost layers, where
> the cost of a walking traveller is accumulated following a rule, that it's
> easier going downhill (until a limit value, which marks the slope where
> going downhill also becomes harder than walking on a flat plane) than
> uphill, can I just enter values for every difference in height that is
> travelled? Can the difference column for example be equal to the
> height-difference and the related factor  value to the amount of energy that
> is used to travel this height difference (or slope)? I'm sorry im new to
> this subject, i've read some articles about the theory but nobody really
> mentions which programs he uses, so I dont't really know where to start.
>
> If my idea about this method is right until now, could I fill the list as
> in the following? (the values are fictional)
>
> difference (in height) -5 factor 5
> difference (in height) -2 factor 3
> difference (in height) 0 factor 4
> difference (in height) 3 factor 5

 difference (in height) 8 factor 10

Would this make sense?

GRASS GIS got a built in algorythm which calculates the walking cost of a
traveller. Which is the algorythm that is used for method A in SEXTANTE?
If I'm right so far, SEXTANTE would allow to calculate cost for different
methods of travelling by just filling out the table with the difference and
it's relating factor, no?

I'm sorry if my post is total crap, but unfortunately I haven't found any
tutorials or anything else which explains how you perform an anisotropic
cost analysis. (the SAGA GIS Manual got some information about it, but
unfortunately I can't enter values for the "difference" in height that is
travelled. It's just done as in method A, but how does this work?
I would be very very grateful for any suggestions or informations, im new to
this subject but want to understand it and perform some analysis.

Thank you
davk
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://listserv.gva.es/pipermail/gvsig_internacional/attachments/20100623/46ddd553/attachment.htm