rsaga.fill.sinks {RSAGA} | R Documentation |
Several methods for filling closed depressions in digital elevation models that would affect hydrological modeling.
rsaga.fill.sinks(in.dem, out.dem, method = "planchon.darboux.2001", out.flowdir, out.wshed, minslope, ...)
in.dem |
Input: digital elevation model (DEM) as SAGA grid file
(default extension: .sgrd ). |
out.dem |
Output: filled, depression-free DEM (SAGA grid file). Existing files will be overwritten! |
method |
The depression filling algorithm to be used (character).
One of "planchon.darboux.2001" (default), "wang.liu.2006" ,
or "xxl.wang.liu.2006" . |
out.flowdir |
(only for "wang.liu.2001" ): Optional
output grid file for computed flow directions (see Notes). |
out.wshed |
(only for "wang.liu.2001" ): Optional
output grid file for watershed basins. |
minslope |
Minimum slope angle (in degree) preserved between adjacent
grid cells (default value of 0.01 only for
method="planchon.darboux.2001" , otherwise no default). |
... |
Optional arguments to be passed to rsaga.geoprocessor ,
including the env RSAGA geoprocessing environment. |
This function bundles three SAGA modules for filling sinks
using three different algorithms (method
argument).
"planchon.darboux.2001"
: The algorithm of
Planchon and Darboux (2001) consists of increasing the elevation
of pixels in closed depressions until the sink disappears and a mininum slope
angle of minslope
(default: 0.01
degree) is established.
"wang.liu.2006"
: This module uses an algorithm proposed by
Wang and Liu (2006) to identify and fill surface depressions in DEMs.
The method was enhanced to allow the creation of hydrologically sound
elevation models, i.e. not only to fill the depressions but also to
preserve a downward slope along the flow path. If desired, this
is accomplished by preserving a minimum slope gradient (and thus
elevation difference) between cells. This is the fully featured
version of the module creating a depression-free DEM, a flow path
grid and a grid with watershed basins. If you encounter problems
processing large data sets (e.g. LIDAR data) with this module
try the basic version (xxl.wang.lui.2006
).
"xxl.wang.liu.2006"
: This modified algorithm after Wang and Liu (2006)
is designed to work on large data sets.
The type of object returned depends on the intern
argument
passed to the rsaga.geoprocessor
. For intern=FALSE
it is a numerical error code (0: success), or otherwise (default)
a character vector with the module's console output.
The function writes SAGA grid files containing of the depression-free
preprocessed DEM, and optionally the flow directions and watershed basins.
The flow directions are coded as 0 = north, 1 = northeast, 2 = east, ..., 7 = northwest.
If minslope=0
, depressions will only be filled until a
horizontal surface is established, which may not be helpful for hydrological
modeling.
Alexander Brenning (R interface), Volker Wichmann (SAGA module)
Planchon, O., and F. Darboux (2001): A fast, simple and versatile algorithm to fill the depressions of digital elevation models. Catena 46: 159-176.
Wang, L. & H. Liu (2006): An efficient method for identifying and filling surface depressions in digital elevation models for hydrologic analysis and modelling. International Journal of Geographical Information Science, Vol. 20, No. 2: 193-213.
rsaga.sink.removal
, rsaga.sink.route
.