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CLaRiNet 0.1 beta >> Ordering streams and traversing networks > FindNetworkTransition

FindNetworkTransition

Locates the cells verifying a transition criterion when moving downstream in a channel network.

Calling Sequence

CELLS = FindNetworkTransition ( handle_ras , handle_fdr , a , b , outlet , niter )

Arguments

hr

integer: handle on the raster which will be used to define the transition criterion.

fdr

integer: handle on the flow direction grid to be used.

a,b

floats: the transition criterion will be verified when the expression (a * #Raster# + b) switches from positive to negative when moving downstream.

outlet

integer: record number (absolute reference in the raster, as returned by XY2rec) of the outlet cell.

nit

integer: number of times that the search for transitions can be performed recursively.

CELLS

output: vector containing the record numbers of the cells verifying the transition criterion.

Description

Locates the cells verifying a transition criterion when moving downstream in a channel network.

Exemples

if the raster elev contains elevation data, then the contour line Z=Z0 in the catchment having its outlet at cell outlet, is given by the set of cells verifying the following transition :

1 * #elev# - Z0 switching from positive to negative when moving downstream, i.e. :

CZ0 = FindNetworkTransition ( elev , fdr , 1 , -Z0 , outlet , 1)

See Also

Authors

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