Raster_StreamExtractionService

Operation:

Our basic processing as follows:

1. Use tardem program flood fill the depressions in DEM
   
2. Use tardem program d8 to get flowdirection based on filled dem
   
3. Use GRASS command r.mfilter to get the curvature, and then use r.mapcalc to threshold the curvature. It is based on the 9×9 Laplacian filter
   
4. Run tardem program aread8 to get flow accumulation using channel segment as weight(derived from threholding curvature grid)
   
5. Use r.mapcalc to threshold flow accumulation to get stream
   

Request Parameters:

sourceURL

URL of input elevation file

Default format: GeoTIFF

tcurv_threshold

threshold tangential curvature

Parameter format: float

flowaccum_threshold

threshold flow accumulation

Parameter format: integer

outputFormatType

Format of output file

Parameter format: string

Options: GeoTIFF,TIFF,ESRI_Shapefile

Default: GeoTIFF

outputGeoTiffType

Type of output GeoTIFF file if outputFormatType is specified as GeoTIFF

Parameter format: string

Options: Byte,Int16,UInt16,UInt32,Int32,Float32,Float64,CInt16,CInt32,CFloat32,CFloat64

Default: Byte

Response Parameters:

returnURL

URL of output file to contain stream segments

returnFormat

Format of output file

For further informations

ServiceLocation
WSDL
JavaInterface

See GRASS command

r.mfilter
r.mapcalc

See also:

Luo, W. and T. F. Stepinski, 2008, "Identification of geologic contrasts from landscape dissection pattern: an application to Cascade Range, Oregon, USA", Geomorphology, 10.1016/j.geomorph.2007.10.014, in press. See at http://www.niu.edu/landform/papers/GEOMOR_2483.pdf.

Molloy,B. I. and T.F. Stepinski, 2007, "Automated Mapping of Valley Networks on Mars", Computers and Geoscience, 33, p728-738.

Tarboton, D.G., and D.P. Ames, 2001, "Advances in the mapping of flow networks from digital elevation data", World Water and Environmental Resources Congress, ASCE, Orlando, Florida. See at http://hydrology.usu.edu/tardem/tardem4.0/.