[GRASS-user] r.terraflow

[G. Allegri]

Thanks Luca.
The coding mapping seems correct. So, zeroes are for unsolved pixels...
I'll do some tests to compare the results with r.watershed. At now
they seem quite different. I'm not sure if I should trust onflow
directions from r.terraflow to use them in r.water.outlet...

2008/7/28 doktoreas <thedoktor78 at gmail.com>:
>
>
>
> G. Allegri wrote:
>>
>> Hi list.
>> I'm trying to use terraflow for the very first time, because
>> r.watershed is too much time consuming for my dataset. I've updated it
>> to include the recent patches to categories coding.
>> In the new coding scheme, when using the sdf option, 9 directions are
>> depicted (0,1,2,4,8,16,32,64,128). I reclassify them to compare the
>> result with r.watershed, but I'm not sure about the 0 values returned
>> by r.terraflow. In r.watershed the positive values, multiplied for 45,
>> give the direction angle relative to north, so 8 directions are used
>> (1-8), and I've setup the following reclassifying rules:
>>
>> 1=2
>> 2=3
>> 4=4
>> 8=5
>> 16=6
>> 32=7
>> 64=8
>> 128=1
>>
>> I miss the zeroes... I've given a rapid look to the source code, and I
>> see it's used as "default" return value. ???
>>
>>
> Hi Giovanni,
> me and Ivan played some time ago with r.terraflow..you can find more info in
> this topic:
> http://www.nabble.com/r.watershed-and-swap-memory-to16116939.html#a16137454
>
> Bye
> Luca
> --
> View this message in context: http://www.nabble.com/r.terraflow-tp18691496p18697525.html
> Sent from the Grass - Users mailing list archive at Nabble.com.
>
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