[QGIS-pt] slope lenght

[Giovanni Manghi]

Olá,


2014-04-30 15:54 GMT+01:00 david pulquerio <pulquerio2003 at yahoo.com>:
> boa tarde!
> alguem me sabe responder se a ferramenta o SAGA no QGIS slope lenght é
> equivalente ao folw accumulation no arcgis.

acho que sim, infelizmente a documentação de SAGA as vezes não ajuda
(estou a dar uma vista de olhos no manual oficial e na "biblia" de
Victor Olaya).

Entretanto acho que ficas bem servido com r.watershed

DESCRIPTION

r.watershed generates a set of maps indicating: 1) flow accumulation,
drainage direction, the location of streams and watershed basins, and
2) the LS and S factors of the Revised Universal Soil Loss Equation
(RUSLE).


Flags:

-f
Enable MFD flow (default is SFD (D8))
SFD: single flow direction, MFD: multiple flow direction
-4
Allow only horizontal and vertical flow of water
-m
Enable disk swap memory option: Operation is slow
Only needed if memory requirements exceed available RAM; see manual on
how to calculate memory requirements
-a
Use positive flow accumulation even for likely underestimates
See manual for a detailed description of flow accumulation output
--overwrite
Allow output files to overwrite existing files
--verbose
Verbose module output
--quiet
Quiet module output
Parameters:

elevation=name
Input map: elevation on which entire analysis is based
depression=name
Input map: locations of real depressions
flow=name
Input map: amount of overland flow per cell
disturbed.land=string
Input map or value: percent of disturbed land, for USLE
blocking=name
Name of input raster map blocking overland surface flow
Input map: terrain blocking overland surface flow, for USLE
accumulation=name
Name for output accumulation raster map
Output map: number of cells that drain through each cell
drainage=name
Output map: drainage direction
basin=name
Output map: basins raster map
stream=name
Output map: stream segments
half.basin=name
Output map: half basins raster map
visual=name
Output map: useful for visual display of results
length.slope=name
Name for output slope length raster map
Output map: slope length and steepness (LS) factor for USLE
slope.steepness=name
Name for output slope steepness raster map
Output map: Slope steepness (S) factor for USLE
threshold=integer
Input value: minimum size of exterior watershed basin
max.slope.length=float
Input value: maximum length of surface flow, for USLE
convergence=integer
Convergence factor for MFD (1-10)
1 = most diverging flow, 10 = most converging flow. Recommended: 5
Default: 5
memory=integer
Maximum memory to be used with -m flag (in MB)
Default: 300




-- 
Giovanni Manghi
Faunalia.pt
Sistemas de Informação Geográfica Open Source
Portugal

Web: http://www.faunalia.pt
Email & Jabber: giovanni.manghi at faunalia.pt
PGP Key available
Tel. + 351 96 7058216
--