Determining whethera slope goes up or down...

[MichalBirkenfeld]

Hi,
I'm trying to create a cost surface for hill walking time expenditure, based on slope and distance.
To do so, I need to know whether at a specific cell the slope is positive (= walking uphill) or negative (= walking downhill).
Any ideas?
Thanks
Michal

[MichalBirkenfeld]

Hallo,

Did I get you right ?

regards,

PS: extent gives a problem I think

Hi!

Thank you for taking the time to help!

You got it exactly right... I don't get what I've done wrong. Are you using ArcMap 10.0?

The only thing I can think of is the table - how is yours built? is it saved as a .txt file?

everything else is exactly spot-on...

Thanks again
Michal

[RamB]

Hallo,

Yes, I am using arcgis 10.
1. I have a dem
2. I have sites as points
3. I select one point of interest, so analysis is done for one selected point.
4. the inputs to the model are a point file with one selected location, the same dem as vertical raster also, a text file with toblers method of vertical factors (-90 to 90), factor has 6 digits after decimal, and degrees and factors are separated by a tab spacing.
5. extent can be default or full extent does not matter, full extent took about 100 minutes to solve ( I have a slow computer)
6. Results are as expected 🙂

please check your txt file is tab separated, check units correspond to your shapefile units

regards

[MichalBirkenfeld]

Well, you got it - the problem must have been the extent.
It took forever to run (apparently my computer is even slower than yours), but with a restricted extent I did get better results.
Now I just have to think how I can double-check the validity of my results... It seems to give a bit too small of a radius.

Thank you very much for your help!
I appreciate it very much!

Michal