[GRASS-user] accumulation map from directions map

Achim Kisseler ak7 at jupiter.uni-freiburg.de
Thu Dec 17 07:42:14 EST 2009


Hi all,

again I reached the point I did half a year ago: jgrass only can handle 
'metric' rasters, which means raster-cells of equal sizes, same NS, OW 
resolution.

I work an a latlon-projection and therefore I cannot use jgrass.

? 1 I guess, r.stream cannot handle latlong-projections?
? 2 I guess, r.stream doesn't have something like h.tca?
     (h.tca: makes an accumulation map from a direction map)

? 3 Is it possible to make the accumulation-values non-integer and 
weight every grid-cell with its real area size? Then every accumulation 
value would indicate its basin-size and so on like in eg. lambert 
projection.

What wouldn't work that easy: distances EW and thus angle based 
calculations, too.

Again my old PROBLEM:
How to get an accumulation map strickly WITHOUT an DEM from ONLY an 
direction map on a LAT-LON map?

Achim



Jarek Jasiewicz schrieb:
> Markus Neteler pisze:
>> On Thu, Nov 19, 2009 at 2:35 PM, Achim Kisseler
>> <ak7 at jupiter.uni-freiburg.de> wrote:
>>  
>>> Dear Markus,
>>>
>>> I follow Silvias suggestion and use h.tca in JGRASS.
>>>
>>> BTW: Isn't is possible to integrate the horton-tools into grass?
>>>     
>>
>> If the license is compliant to GPL (I guess so), yes.
>>   
> Hortons tools are available in svn add ons as r.stream.* suite: 
> r.stream.extract, r.stream.order, r.stream.stats etc... see tutorial on 
> grass wiki
> http://grass.osgeo.org/wiki/R.stream.*
> Jarek
> 
>> Markus
>> _______________________________________________
>> grass-user mailing list
>> grass-user at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/grass-user
>>   
> 


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